Chapter 4101:8-8 Roof-Ceiling Construction

4101:8-8-01 [Effective until 7/1/2019] Roof-ceiling construction.

[Comment: When a reference is made within this rule to a federal statutory provision, an industry consensus standard, or any other technical publication, the specific date and title of the publication as well as the name and address of the promulgating agency are listed in rule 4101:8-44-01 of the Administrative Code. The application of the referenced standards shall be limited and as prescribed in section 102.5 of rule 4101:8-1-01 of the Administrative Code.]

SECTION 801

GENERAL

801.1 Application. The provisions of this chapter shall control the design and construction of the roof-ceiling system for all buildings.

801.2 Requirements. Roof and ceiling construction shall be capable of accommodating all loads imposed according to Section 301 and of transmitting the resulting loads to the supporting structural elements.

801.3 Roof drainage. In areas where expansive or collapsible soils are known to exist, all dwellings shall have a controlled method of water disposal from roofs that will collect and discharge roof drainage to the ground surface at least 5 feet (1524 mm) from foundation walls or to an approved drainage system.

Exception: The minimum distance shall not apply when the discharge occurs on the exterior side of walls where the building official determines such drainage will not be detrimental to the building performance.

SECTION 802

WOOD ROOF FRAMING

802.1 Identification. Load-bearing dimension lumber for rafters, trusses and ceiling joists shall be identified by a grade mark of a lumber grading or inspection agency that has been approved by an accreditation body that complies with DOC PS 20. In lieu of a grade mark, a certificate of inspection issued by a lumber grading or inspection agency meeting the requirements of this section shall be accepted.

802.1.1 Blocking. Blocking shall be a minimum of utility grade lumber.

802.1.2 End-jointed lumber. Approved end-jointed lumber identified by a grade mark conforming to Section 802.1 may be used interchangeably with solid-sawn members of the same species and grade.

802.1.3 Fire-retardant-treated wood. Fire-retardant treated wood (FRTW) is any wood product which, when impregnated with chemicals by a pressure process or other means during manufacture, shall have, when tested in accordance with ASTM E 84, a listed flame spread index of 25 or less and shows no evidence of significant progressive combustion when the test is continued for an additional 20-minute period. In addition, the flame front shall not progress more than 10.5 feet (3200 mm) beyond the center line of the burners at any time during the test.

802.1.3.1 Pressure process. For wood products impregnated with chemicals by a pressure process, the process shall be performed in closed vessels under pressures not less than 50 pounds per square inch gauge (psig) ( 344.7 kPa).

802.1.3.2 Other means during manufacture. For wood products produced by other means during manufacture the treatment shall be an integral part of the manufacturing process of the wood product. The treatment shall provide permanent protection to all surfaces of the wood product.

802.1.3.3 Testing. For wood products produced by other means during manufacture, other than a pressure process, all sides of the wood product shall be tested in accordance with and produce the results required in Section 802.1.3. Testing of only the front and back faces of wood structural panels shall be permitted.

802.1.3.4 Labeling. Fire-retardant-treated lumber and wood structural panels shall be labeled. The label shall contain:

1. The identification mark of an approved agency in accordance with Section 1703.5 of the "Ohio Building Code".

2. Identification of the treating manufacturer.

3. The name of the fire-retardant treatment.

4. The species of wood treated.

5. Flame spread index and smoke-developed index.

6. Method of drying after treatment.

7. Conformance to applicable standards in accordance with Sections 802.1.3.5 through 802.1.3.8.

8. For FRTW exposed to weather, or a damp or wet location, the words "No increase in the listed classification when subjected to the Standard Rain Test" (ASTM D 2898).

802.1.3.5 Strength adjustments. Design values for untreated lumber and wood structural panels as specified in Section 802.1 shall be adjusted for fire-retardant-treated wood. Adjustments to design values shall be based upon an approved method of investigation which takes into consideration the effects of the anticipated temperature and humidity to which the fire-retardant-treated wood will be subjected, the type of treatment and redrying procedures.

802.1.3.5.1 Wood structural panels. The effect of treatment and the method of redrying after treatment, and exposure to high temperatures and high humidities on the flexure properties of fire-retardant-treated softwood plywood shall be determined in accordance with ASTM D 5516. The test data developed by ASTM D 5516 shall be used to develop adjustment factors, maximum loads and spans, or both for untreated plywood design values in accordance with ASTM D 6305. Each manufacturer shall publish the allowable maximum loads and spans for service as floor and roof sheathing for their treatment.

802.1.3.5.2 Lumber. For each species of wood treated, the effect of the treatment and the method of redrying after treatment and exposure to high temperatures and high humidities on the allowable design properties of fire-retardant-treated lumber shall be determined in accordance with ASTM D 5664. The test data developed by ASTM D 5664 shall be used to develop modification factors for use at or near room temperature and at elevated temperatures and humidity in accordance with ASTM D 6841. Each manufacturer shall publish the modification factors for service at temperatures of not less than 80°F (27°C) and for roof framing. The roof framing modification factors shall take into consideration the climatological location.

802.1.3.6 Exposure to weather. Where fire-retardant-treated wood is exposed to weather or damp or wet locations, it shall be identified as "Exterior" to indicate there is no increase in the listed flame spread index as defined in Section 802.1.3 when subjected to ASTM D 2898.

802.1.3.7 Interior applications. Interior fire-retardant-treated wood shall have a moisture content of not over 28 percent when tested in accordance with ASTM D 3201 procedures at 92 percent relative humidity. Interior fire-retardant-treated wood shall be tested in accordance with Section 802.1.3.5.1 or 802.1.3.5.2. Interior fire-retardant-treated wood designated as Type A shall be tested in accordance with the provisions of this section.

802.1.3.8 Moisture content. Fire-retardant-treated wood shall be dried to a moisture content of 19 percent or less for lumber and 15 percent or less for wood structural panels before use. For wood kiln dried after treatment (KDAT) the kiln temperatures shall not exceed those used in kiln drying the lumber and plywood submitted for the tests described in Section 802.1.3.5.1 for plywood and 802.1.3.5.2 for lumber.

802.1.4 Structural glued laminated timbers. Glued laminated timbers shall be manufactured and identified as required in ANSI/AITC A 190.1 and ASTM D 3737.

802.1.5 Structural log members. Stress grading of structural log members of nonrectangular shape, as typically used in log buildings, shall be in accordance with ASTM D 3957. Such structural log members shall be identified by the grade mark of an approved lumber grading or inspection agency. In lieu of a grade mark on the material, a certificate of inspection as to species and grade issued by a lumber-grading or inspection agency meeting the requirements of this section shall be permitted to be accepted.

802.2 Design and construction. The framing details required in Section 802 apply to roofs having a minimum slope of three units vertical in 12 units horizontal (25-percent slope) or greater. Roof-ceilings shall be designed and constructed in accordance with the provisions of this chapter and Figures 606.11(1), 606.11(2) and 606.11(3) or in accordance with AFPA/NDS. Components of roof-ceilings shall be fastened in accordance with Table 602.3(1).

802.3 Framing details. Rafters shall be framed to ridge board or to each other with a gusset plate as a tie. Ridge board shall be at least 1-inch (25 mm) nominal thickness and not less in depth than the cut end of the rafter. At all valleys and hips there shall be a valley or hip rafter not less than 2-inch (51 mm) nominal thickness and not less in depth than the cut end of the rafter. Hip and valley rafters shall be supported at the ridge by a brace to a bearing partition or be designed to carry and distribute the specific load at that point. Where the roof pitch is less than three units vertical in 12 units horizontal (25-percent slope), structural members that support rafters and ceiling joists, such as ridge beams, hips and valleys, shall be designed as beams.

802.3.1 Ceiling joist and rafter connections. Ceiling joists and rafters shall be nailed to each other in accordance with Table 802.5.1(9), and the rafter shall be nailed to the top wall plate in accordance with Table 602.3(1). Ceiling joists shall be continuous or securely joined in accordance with Table 802.5.1(9) where they meet over interior partitions and are nailed to adjacent rafters to provide a continuous tie across the building when such joists are parallel to the rafters.

Where ceiling joists are not connected to the rafters at the top wall plate, joists connected higher in the attic shall be installed as rafter ties, or rafter ties shall be installed to provide a continuous tie. Where ceiling joists are not parallel to rafters, rafter ties shall be installed. Rafter ties shall be a minimum of 2-inch by 4-inch (51 mm by 102 mm) (nominal), installed in accordance with the connection requirements in Table 802.5.1(9), or connections of equivalent capacities shall be provided. Where ceiling joists or rafter ties are not provided, the ridge formed by these rafters shall be supported by a wall or girder designed in accordance with accepted engineering practice.

Collar ties or ridge straps to resist wind uplift shall be connected in the upper third of the attic space in accordance with Table 602.3(1).

Collar ties shall be a minimum of 1-inch by 4-inch (25 mm by 102 mm) (nominal), spaced not more than 4 feet (1219 mm) on center.

802.3.2 Ceiling joists lapped. Ends of ceiling joists shall be lapped a minimum of 3 inches (76 mm) or butted over bearing partitions or beams and toenailed to the bearing member. When ceiling joists are used to provide resistance to rafter thrust, lapped joists shall be nailed together in accordance with Table 602.3(1) and butted joists shall be tied together in a manner to resist such thrust.

802.4 Allowable ceiling joist spans. Spans for ceiling joists shall be in accordance with Tables 802.4(1) and 802.4(2). For other grades and species and for other loading conditions, refer to the AF&PA Span Tables for Joists and Rafters.

802.5 Allowable rafter spans. Spans for rafters shall be in accordance with Tables 802.5.1(1) through 802.5.1(8). For other grades and species and for other loading conditions, refer to the AF&PA Span Tables for Joists and Rafters. The span of each rafter shall be measured along the horizontal projection of the rafter.

802.5.1 Purlins. Installation of purlins to reduce the span of rafters is permitted as shown in Figure 802.5.1. Purlins shall be sized no less than the required size of the rafters that they support. Purlins shall be continuous and shall be supported by 2-inch by 4-inch (51 mm by 102 mm) braces installed to bearing walls at a slope not less than 45 degrees from the horizontal. The braces shall be spaced not more than 4 feet (1219 mm) on center and the unbraced length of braces shall not exceed 8 feet (2438 mm).

802.6 Bearing. The ends of each rafter or ceiling joist shall have not less than 11/2 inches (38 mm) of bearing on wood or metal and not less than 3 inches (76 mm) on masonry or concrete.

802.6.1 Finished ceiling material. If the finished ceiling material is installed on the ceiling prior to the attachment of the ceiling to the walls, such as in construction at a factory, a compression strip of the same thickness as the finish ceiling material shall be installed directly above the top plate of bearing walls if the compressive strength of the finish ceiling material is less than the loads it will be required to withstand. The compression strip shall cover the entire length of such top plate and shall be at least one-half the width of the top plate. It shall be of material capable of transmitting the loads transferred through it.

802.7 Cutting and notching. Structural roof members shall not be cut, bored or notched in excess of the limitations specified in this section.

802.7.1 Sawn lumber. Notches in solid lumber joists, rafters, blocking and beams shall not exceed one-sixth of the depth of the member, shall not be longer than one-third of the depth of the member and shall not be located in the middle one-third of the span. Notches at the ends of the member shall not exceed one-fourth the depth of the member. The tension side of members 4 inches (102 mm) or greater in nominal thickness shall not be notched except at the ends of the members. The diameter of the holes bored or cut into members shall not exceed one-third the depth of the member. Holes shall not be closer than 2 inches (51 mm) to the top or bottom of the member, or to any other hole located in the member. Where the member is also notched, the hole shall not be closer than 2 inches (51 mm) to the notch.

Exception: Notches on cantilevered portions of rafters are permitted provided the dimension of the remaining portion of the rafter is not less than 4-inch nominal (102 mm) and the length of the cantilever does not exceed 24 inches (610 mm).

802.7.2 Engineered wood products. Cuts, notches and holes bored in trusses, structural composite lumber, structural glue-laminated members or I-joists are prohibited except where permitted by the manufacturer's recommendations or where the effects of such alterations are specifically considered in the design of the member by a registered design professional

802.8 Lateral support. Roof framing members and ceiling joists having a depth-to-thickness ratio exceeding 5 to 1 based on nominal dimensions shall be provided with lateral support at points of bearing to prevent rotation. For roof rafters with ceiling joists attached per Table 602.3(1), the depth-thickness ratio for the total assembly shall be determined using the combined thickness of the rafter plus the attached ceiling joist.

Exception: Roof trusses shall be braced in accordance with Section 802.10.3.

802.8.1 Bridging. Rafters and ceiling joists having a depth-to-thickness ratio exceeding 6 to 1 based on nominal dimensions shall be supported laterally by solid blocking, diagonal bridging (wood or metal) or a continuous 1-inch by 3-inch (25mmby76mm) wood strip nailed across the rafters or ceiling joists at intervals not exceeding 8 feet (2438 mm).

802.9 Framing of openings. Openings in roof and ceiling framing shall be framed with header and trimmer joists. When the header joist span does not exceed 4 feet (1219 mm), the header joist may be a single member the same size as the ceiling joist or rafter. Single trimmer joists may be used to carry a single header joist that is located within 3 feet (914 mm) of the trimmer joist bearing. When the header joist span exceeds 4 feet (1219 mm), the trimmer joists and the header joist shall be doubled and of sufficient cross section to support the ceiling joists or rafter framing into the header. Approved hangers shall be used for the header joist to trimmer joist connections when the header joist span exceeds 6 feet (1829 mm). Tail joists over 12 feet (3658 mm) long shall be supported at the header by framing anchors or on ledger strips not less than 2 inches by 2 inches (51 mm by 51 mm).

802.10 Wood trusses.

802.10.1 Truss design drawings. Truss design drawings, prepared in conformance to Section 802.10.1, shall be provided to the building official and approved prior to installation. Truss design drawings shall include, at a minimum, the information specified below. Truss design drawing shall be provided with the shipment of trusses delivered to the jobsite.

1 Slope or depth, span and spacing.

2 Location of all joints.

3 Required bearing widths.

4. Design loads as applicable.

4.

1. Top chord live load (as determined from Section 301.6 ).

4.

2. Top chord dead load.

4.

3. Bottom chord live load.

4.

4. Bottom chord dead load.

5. Concentrated loads and their points of application.

6. Controlling wind and earthquake loads.

5. Adjustments to lumber and joint connector design values for conditions of use.

6. Each reaction force and direction.

7. Joint connector type and description (e.g., size, thickness or gage) and the dimensioned location of each joint connector except where symmetrically located relative to the joint interface.

8. Lumber size, species and grade for each member.

9. Connection requirements for:

9.

1. Truss to girder-truss.

9.

2. Truss ply to ply.

9.

3. Field splices.

10. Calculated deflection ratio and/or maximum description for live and total load.

11. Maximum axial compression forces in the truss members to enable the building designer to design the size, connections and anchorage of the permanent continuous lateral bracing. Forces shall be shown on the truss design drawing or on supplemental documents.

12. Required permanent truss member bracing location.

802.10.2 Design. Wood trusses shall be designed in accordance with accepted engineering practice. The design and manufacture of metal-plate-connected wood trusses shall comply with ANSI/TPI 1. The truss design drawings shall be prepared by a registered professional where required by the statutes of the jurisdiction in which the project is to be constructed in accordance with Section 106.1.

802.10.2.1 Applicability limits. The provisions of this section shall control the design of truss roof framing when snow controls for buildings not greater than 60 feet (18 288 mm) in length perpendicular to the joist, rafter or truss span, not greater than 36 feet (10 973 mm) in width parallel to the joist, rafter or truss span, not greater than two stories in height with each story not greater than 10 feet (3048 mm) high, and roof slopes not smaller than 3:12 (25-percent slope) or greater than 12:12 (100-percent slope). Truss roof framing constructed in accordance with the provisions of this section shall be limited to sites subjected to a maximum design wind speed of 110 miles per hour (49 m/s), Exposure A, B or C, and a maximum ground snow load of 70 psf (3352 Pa). For consistent loading of all truss types, roof snow load is to be computed as: 0.7 pg.

802.10.3 Bracing. Trusses shall be braced to prevent rotation and provide lateral stability in accordance with the requirements specified in the construction documents for the building and on the individual truss design drawings. In the absence of specific bracing requirements, trusses shall be braced in accordance with the Building Component Safety Information (BCSI 1-03) Guide to Good Practice for Handling, Installing & Bracing of Metal Plate Connected Wood Trusses.

802.10.4 Alterations to trusses. Truss members shall not be cut, notched, drilled, spliced or otherwise altered in any way without the approval of a registered design professional. Alterations resulting in the addition of load (e.g., HVAC equipment, water heater) that exceeds the design load for the truss shall not be permitted without verification that the truss is capable of supporting such additional loading.

802.10.5 Truss to wall connection. Trusses shall be connected to wall plates by the use of approved connectors having a resistance to uplift of not less than 175 pounds (779 N) and shall be installed in accordance with the manufacturer's specifications. For roof assemblies subject to wind uplift pressures of 20 pounds per square foot (960 Pa) or greater, as established in Table 301.2(2), adjusted for height and exposure per Table 301.2(3), see section 802.11.

802.11 Roof tie-down.

802.11.1 Uplift resistance. Roof assemblies which are subject to wind uplift pressures of 20 pounds per square foot (960 Pa) or greater shall have roof rafters or trusses attached to their supporting wall assemblies by connections capable of providing the resistance required in Table 802.11. Wind uplift pressures shall be determined using an effective wind area of 100 square feet ( 9.3 m2) and Zone 1 in Table 301.2(2), as adjusted for height and exposure per Table 301.2(3).

A continuous load path shall be designed to transmit the uplift forces from the rafter or truss ties to the foundation.

TABLE 802.4(1)

CEILING JOIST SPANS FOR COMMON LUMBER SPECIES

(Uninhabitable attics without storage, live load = 10 psf, L/[DELTA]= 240)

CEILING JOIST (inches) SPECIES AND GRADE DEAD LOAD = 5 psf
2 x 4 2 x 6 2 x 8 2 x 10
Maximum ceiling joist spans
(feet-inches) (feet-inches) (feet-inches) (feet-inches)
12 Douglas fir-larch SS 13-2 20-8 Note a Note a
Douglas fir-larch #1 12-8 19-11 Note a Note a
Douglas fir-larch #2 12-5 19-6 25-8 Note a
Douglas fir-larch #3 10-10 15-10 20-1 24-6
Hem-fir SS 12-5 19-6 25-8 Note a
Hem-fir #1 12-2 19-1 25-2 Note a
Hem-fir #2 11-7 18-2 24-0 Note a
Hem-fir #3 10-10 15-10 20-1 24-6
Southern pine SS 12-11 20-3 Note a Note a
Southern pine #1 12-8 19-11 Note a Note a
Southern pine #2 12-5 19-6 25-8 Note a
Southern pine #3 11-6 17-0 21-8 25-7
Spruce-pine-fir SS 12-2 19-1 25-2 Note a
Spruce-pine-fir #1 11-10 18-8 24-7 Note a
Spruce-pine-fir #2 11-10 18-8 24-7 Note a
Spruce-pine-fir #3 10-10 15-10 20-1 24-6
16 Douglas fir-larch SS 11-11 18-9 24-8 Note a
Douglas fir-larch #1 11-6 18-1 23-10 Note a
Douglas fir-larch #2 11-3 17-8 23-0 Note a
Douglas fir-larch #3 9-5 13-9 17-5 21-3
Hem-fir SS 11-3 17-8 23-4 Note a
Hem-fir #1 11-0 17-4 22-10 Note a
Hem-fir #2 10-6 16-6 21-9 Note a
Hem-fir #3 9-5 13-9 17-5 21-3
Southern pine SS 11-9 18-5 24-3 Note a
Southern pine #1 11-6 18-1 23-1 Note a
Southern pine #2 11-3 17-8 23-4 Note a
Southern pine #3 10-0 14-9 18-9 22-2
Spruce-pine-fir SS 11-0 17-4 22-10 Note a
Spruce-pine-fir #1 10-9 16-11 22-4 Note a
Spruce-pine-fir #2 10-9 16-11 22-4 Note a
Spruce-pine-fir #3 9-5 13-9 17-5 21-3
19.2 Douglas fir-larch SS 11-3 17-8 23-3 Note a
Douglas fir-larch #1 10-10 17-0 22-5 Note a
Douglas fir-larch #2 10-7 16-7 21-0 25-8
Douglas fir-larch #3 8-7 12-6 15-10 19-5
Hem-fir SS 10-7 16-8 21-11 Note a
Hem-fir #1 10-4 16-4 21-6 Note a
Hem-fir #2 9-11 15-7 20-6 25-3
Hem-fir #3 8-7 12-6 15-10 19-5
Southern -pine SS 11-0 17-4 22-10 Note a
Southern pine #1 10-10 17-0 22-5 Note a
Southern pine #2 10-7 16-8 21-11 Note a
Southern pine #3 9-1 13-6 17-2 20-3
Spruce-pine-fir SS 10-4 16-4 21-6 Note a
Spruce-pine-fir #1 10-2 15-11 21-0 25-8
Spruce-pine-fir #2 10-2 15-11 21-0 25-8
Spruce-pine-fir #3 8-7 12-6 15-10 19-5
24 Douglas fir-larch SS 10-5 16-4 21-7 Note a
Douglas fir-larch #1 10-0 15-9 20-1 24-6
Douglas fir-larch #2 9-10 14-10 18-9 22-11
Douglas fir-larch #3 7-8 11-2 14-2 17-4
Hem-fir SS 9-10 15-6 20-5 Note a
Hem-fir #1 9-8 15-2 19-7 23-11
Hem-fir #2 9-2 14-5 18-6 22-7
Hem-fir #3 7-8 11-2 14-2 17-4
Southern pine SS 10-3 16-1 21-2 Note a
Southern pine #1 10-0 15-9 20-10 Note a
Southern pine #2 9-10 15-6 20-1 23-11
Southern pine #3 8-2 12-0 15-4 18-1
Spruce-pine-fir SS 9-8 15-2 19-11 25-5
Spruce-pine-fir #1 9-5 14-9 18-9 22-11
Spruce-pine-fir #2 9-5 14-9 18-9 22-11
Spruce-pine-fir #3 7-8 11-2 14-2 17-4

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Span exceeds 26 feet in length.

TABLE 802.4(2)

CEILING JOIST SPANS FOR COMMON LUMBER SPECIES

(Uninhabitable attics with limited storage, live load = 20 psf, L/[DELTA] = 240)

CEILING JOIST SPACING (inches) SPECIES AND GRADE DEAD LOAD = 10 psf
2 x 4 2 x 6 2 x 8 2 x 10
Maximum ceiling joist spans
(feet-inches) (feet-inches) (feet-inches) (feet-inches)
12 Douglas fir-larch SS 10-5 16-4 21-7 Note a
Douglas fir-larch #1 10-0 15-9 20-1 24-6
Douglas fir-larch #2 9-10 14-10 18-9 22-11
Douglas fir-larch #3 7-8 11-2 14-2 17-4
Hem-fir SS 9-10 15-6 20-5 Note a
Hem-fir #1 9-8 15-2 19-7 23-11
Hem-fir #2 9-2 14-5 18-6 22-7
Hem-fir #3 7-8 11-2 14-2 17-4
Southern pine SS 10-3 16-1 21-2 Note a
Southern pine #1 10-0 15-9 20-10 Note a
Southern pine #2 9-10 15-6 20-1 23-11
Southern pine #3 8-2 12-0 15-4 18-1
Spruce-pine-fir SS 9-8 15-2 19-11 25-5
Spruce-pine-fir #1 9-5 14-9 18-9 22-11
Spruce-pine-fir #2 9-5 14-9 18-9 22-11
Spruce-pine-fir #3 7-8 11-2 14-2 17-4
16 Douglas fir-larch SS 9-6 14-11 19-7 25-0
Douglas fir-larch #1 9-1 13-9 17-5 21-3
Douglas fir-larch #2 8-9 12-10 16-3 19-10
Douglas fir-larch #3 6-8 9-8 12-4 15-0
Hem-fir SS 8-11 14-1 18-6 23-8
Hem-fir #1 8-9 13-5 16-10 20-8
Hem-fir #2 8-4 12-8 16-0 19-7
Hem-fir #3 6-8 9-8 12-4 15-0
Southern pine SS 9-4 14-7 19-3 24-7
Southern pine #1 9-1 14-4 18-11 23-1
Southern pine #2 8-11 13-6 17-5 20-9
Southern pine #3 7-1 10-5 13-3 15-8
Spruce-pine-fir SS 8-9 13-9 18-1 23-1
Spruce-pine-fir #1 8-7 12-10 16-3 19-10
Spruce-pine-fir #2 8-7 12-10 16-3 19-10
Spruce-pine-fir #3 6-8 9-8 12-4 15-0
19.2 Douglas fir-larch SS 8-11 14-0 18-5 23-4
Douglas fir-larch #1 8-7 12-6 15-10 19-5
Douglas fir-larch #2 8-0 11-9 14-10 18-2
Douglas fir-larch #3 6-1 8-10 11-3 13-8
Hem-fir SS 8-5 13-3 17-5 22-3
Hem-fir #1 8-3 12-3 15-6 18-11
Hem-fir #2 7-10 11-7 14-8 17-10
Hem-fir #3 6-1 8-10 11-3 13-8
Southern pine SS 8-9 13-9 18-1 23-1
Southern pine #1 8-7 13-6 17-9 21-1
Southern pine #2 8-5 12-3 15-10 18-11
Southern pine #3 6-5 9-6 12-1 14-4
Spruce-pine-fir SS 8-3 12-11 17-1 21-8
Spruce-pine-fir #1 8-0 11-9 14-10 18-2
Spruce-pine-fir #2 8-0 11-9 14-10 18-2
Spruce-pine-fir #3 6-1 8-10 11-3 13-8
24 Douglas fir-larch SS 8-3 13-0 17-1 20-11
Douglas fir-larch #1 7-8 11-2 14-2 17-4
Douglas fir-larch #2 7-2 10-6 13-3 16-3
Douglas fir-larch #3 5-5 7-11 10-0 12-3
Hem-fir SS 7-10 12-3 16-2 20-6
Hem-fir #1 7-6 10-11 13-10 16-11
Hem-fir #2 7-1 10-4 13-1 16-0
Hem-fir #3 5-5 7-11 10-0 12-3
Southern pine SS 8-1 12-9 16-10 21-6
Southern pine #1 8-0 12-6 15-10 18-10
Southern pine #2 7-8 11-0 14-2 16-11
Southern pine #3 5-9 8-6 10-10 12-10
Spruce-pine-fir SS 7-8 12-0 15-10 19-5
Spruce-pine-fir #1 7-2 10-6 13-3 16-3
Spruce-pine-fir #2 7-2 10-6 13-3 16-3
Spruce-pine-fir #3 5-5 17-11 10-0 12-3

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Span exceeds 26 feet in length.

TABLE 802.5.1(1)

RAFTER SPANS FOR COMMON LUMBER SPECIES

(Roof live load=20 psf, ceiling not attached to rafters, L/ [DELTA]= 180)

RAFTER SPACING (inches) SPECIES AND GRADE DEAD LOAD = 10 psf DEAD LOAD = 20 psf
2 x 4 2 x 6 2 x 8 2 x 10 2 x 12 2 x 4 2 x 6 2 x 8 2 x 10 2 x 12
Maximum rafter spansa
(feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches)
12 Douglas fir-larch SS 11-6 18-0 23-9 Note b Note b 11-6 18-0 23-5 Note b Note b
Douglas fir-larch #1 11-1 17-4 22-5 Note b Note b 10-6 15-4 19-5 23-9 Note b
Douglas fir-larch #2 10-10 16-7 21-0 25-8 Note b 9-10 14-4 18-2 22-3 25-9
Douglas fir-larch #3 8-7 12-6 15-10 19-5 22-6 7-5 10-10 13-9 16-9 19-6
Hem-fir SS 10-10 17-0 22-5 Note b Note b 10-10 17-0 22-5 Note b Note b
Hem-fir #1 10 -7 16-8 21-10 Note b Note b 10-3 14-11 18-11 23-2 Note b
Hem-fir #2 10-1 15-11 20-8 25-3 Note b 9-8 14-2 17-11 21-11 25-5
Hem-fir #3 8-7 12-6 15-10 19-5 22-6 7-5 10-10 13-9 16-9 19-6
Southern pine SS 11-3 17-8 23-4 Note b Note b 11-3 17-8 23-4 Note b Note b
Southern pine #1 11-1 17-4 22-11 Note b Note b 11-1 17-3 21-9 25-10 Note b
Southern pine #2 10-10 17-0 22-5 Note b Note b 10-6 15-1 19-5 23-2 Note b
Southern pine #3 9-1 13-6 17-2 20-3 24-1 7-11 11-8 14-10 17-6 20-11
Spruce-pine-fir SS 10-7 16-8 21-11 Note b Note b 10-7 16-8 21-9 Note b Note b
Spruce-pine-fir #1 10-4 16-3 21-0 25-8 Note b 9-10 14-4 18-2 22-3 25-9
Spruce-pine-fir #2 10-4 16-3 21-0 25-8 Note b 9-10 14-4 18-2 22-3 25-9
Spruce-pine-fir #3 8-7 12-6 15-10 19-5 22-6 7-5 10-10 13-9 16-9 19-6
16 Douglas fir-larch SS 10-5 16-4 21-7 Note b Note b 10-5 16-0 20-3 24-9 Note b
Douglas fir-larch #1 10-0 15-4 19-5 23-9 Note b 9-1 13-3 16-10 20-7 23-10
Douglas fir-larch #2 9-10 14-4 18-2 22-3 25-9 8-6 12-5 15-9 19-3 22-4
Douglas fir-larch #3 7-5 10-10 13-9 16-9 19-6 6-5 9-5 11-11 14-6 16-10
Hem-fir SS 9-10 15-6 20-5 Note b Note b 9-10 15-6 19-11 24-4 Note b
Hem-fir #1 9-8 14-11 18-11 23-2 Note b 8-10 12-11 16-5 20-0 23-3
Hem-fir #2 9-2 14-2 17-11 21-11 25-5 8-5 12-3 15-6 18-11 22-0
Hem-fir #3 7-5 10-10 13-9 16-9 19-6 6-5 9-5 11-11 14-6 16-10
Southern pine SS 10-3 16-1 21-2 Note b Note b 10-3 16-1 21-2 Note b Note b
Southern pine #1 10-0 15-9 20-10 25-10 Note b 10-0 15-0 18-10 22-4 Note b
Southern pine #2 9-10 15-1 19-5 23-2 Note b 9-1 13-0 16-10 20-1 23-7
Southern pine #3 7-11 11-8 14-10 17-6 20-11 6-10 10-1 12-10 15-2 18-1
Spruce-pine-fir SS 9-8 15-2 19-11 25-5 Note b 9-8 14-10 18-10 23-0 Note b
Spruce-pine-fir #1 9-5 14-4 18-2 22-3 25-9 8-6 12-5 15-9 19-3 22-4
Spruce-pine-fir #2 9-5 14-4 18-2 22-3 25-9 8-6 12-5 15-9 19-3 22-4
Spruce-pine-fir #3 7-5 10-10 13-9 16-9 19-6 6-5 9-5 11-11 14-6 16-10
19.2 Douglas fir-larch SS 9-10 15-5 20-4 25-11 Note b 9-10 14-7 18-6 22-7 Note b
Douglas fir-larch #1 9-5 14-0 17-9 21-8 25-2 8-4 12-2 15-4 18-9 21-9
Douglas fir-larch #2 8-11 13-1 16-7 20-3 23-6 7-9 11-4 14-4 17-7 20-4
Douglas fir-larch #3 6-9 9-11 12-7 15-4 17-9 5-10 8-7 10-10 13-3 15-5
Hem-fir SS 9-3 14-7 19-2 24-6 Note b 9-3 14-4 18-2 22-3 25-9
Hem-fir #1 9-1 13-8 17-4 21-1 24-6 8-1 11-10 15-0 18-4 21-3
Hem-fir #2 8-8 12-11 16-4 20-0 23-2 7-8 11-2 14-2 17-4 20-1
Hem-fir #3 6-9 9-11 12-7 15-4 17-9 5-10 8-7 10-10 13-3 15-5
Southern pine SS 9-8 15-2 19-11 25-5 Note b 9-8 15-2 19-11 25-5 Note b
Southern pine #1 9-5 14-10 19-7 23-7 Note b 9-3 13-8 17-2 20-5 24-4
Southern pine #2 9-3 13-9 17-9 21-2 24-10 8-4 11-11 15-4 18-4 21-6
Southern pine #3 7-3 10-8 13-7 16-0 19-1 6-3 9-3 11-9 13-10 16-6
Spruce-pine-fir SS 9-1 14-3 18-9 23-11 Note b 9-1 13-7 17-2 21-0 24-4
Spruce-pine-fir #1 8-10 13-1 16-7 20-3 23-6 7-9 11-4 14-4 17-7 20-4
Spruce-pine-fir #2 8-10 13-1 16-7 20-3 23-6 7-9 11-4 14-4 17-7 20-4
Spruce-pine-fir #3 6-9 9-11 12-7 15-4 17-9 5-10 8-7 10-10 13-3 15-5
24 Douglas fir-larch SS 9-1 14-4 18-10 23-4 Note b 8-11 13-1 16-7 20-3 23-5
Douglas fir-larch #1 8-7 12-6 15-10 19-5 22-6 7-5 10-10 13-9 16-9 19-6
Douglas fir-larch #2 8-0 11-9 14-10 18-2 21-0 6-11 10-2 12-10 15-8 18-3
Douglas fir-larch #3 6-1 8-10 11-3 13-8 15-11 5-3 7-8 9-9 11-10 13-9
Hem-fir SS 8-7 13-6 17-10 22-9 Note b 8-7 12-10 16-3 19-10 23-0
Hem-fir #1 8-4 12-3 15-6 18-11 21-11 7-3 10-7 13-5 16-4 19-0
Hem-fir #2 7-11 11-7 14-8 17-10 20-9 6-10 10-0 12-8 15-6 17-11
Hem-fir #3 6-1 8-10 11-3 13-8 15-11 5-3 7-8 9-9 11-10 13-9
Southern pine SS 8-11 14-1 18-6 23-8 Note b 8-11 14-1 18-6 22-11 Note b
Southern pine #1 8-9 13-9 17-9 21-1 25-2 8-3 12-3 15-4 18-3 21-9
Southern pine #2 8-7 12-3 15-10 18-11 22-2 7-5 10-8 13-9 16-5 19-3
Southern pine #3 6-5 9-6 12-1 14-4 17-1 5-7 8-3 10-6 12-5 14-9
Spruce-pine-fir SS 8-5 13-3 17-5 21-8 25-2 8-4 12-2 15-4 18-9 21-9
Spruce-pine-fir #1 8-0 11-9 14-10 18-2 21-0 6-11 10-2 12-10 15-8 18-3
Spruce-pine-fir #2 8-0 11-9 14-10 18-2 21-0 6-11 10-2 12-10 15-8 18-3
Spruce-pine-fir #3 6-1 8-10 11-3 13-8 15-11 5-3 7-8 9-9 11-10 13-9

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. When ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the factors given below:

HC/HR Rafter Span Adjustment Factor
1/3 0.67
1/4 0.76
1/5 0.83
1/6 0.90
1/ 7.5 or less 1.00

where:

HC= Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

HR= Height of roof ridge measured vertically above the top of the rafter support walls.

b. Span exceeds 26 feet in length.

TABLE 802.5.1(2)

RAFTER SPANS FOR COMMON LUMBER SPECIES

(Roof live load=20 psf, ceiling attached to rafters, L/ [DELTA] = 240)

RAFTER SPACING (inches) SPECIES AND GRADE DEAD LOAD = 10 psf DEAD LOAD = 20 psf
2 x 4 2 x 6 2 x 8 2 x 10 2 x 12 2 x 4 2 x 6 2 x 8 2 x 10 2 x 12
Maximum rafter spansa
(feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches)
12 Douglas fir-larch SS 10-5 16-4 21-7 Note b Note b 10-5 16-4 21-7 Note b Note b
Douglas fir-larch #1 10-0 15-9 20-10 Note b Note b 10-0 15-4 19-5 23-9 Note b
Douglas fir-larch #2 9-10 15-6 20-5 25-8 Note b 9-10 14-4 18-2 22-3 25-9
Douglas fir-larch #3 8-7 12-6 15-10 19-5 22-6 7-5 10-10 13-9 16-9 19-6
Hem-fir SS 9-10 15-6 20-5 Note b Note b 9-10 15-6 20-5 Note b Note b
Hem-fir #1 9-8 15-2 19-11 25-5 Note b 9-8 14-11 18-11 23-2 Note b
Hem-fir #2 9-2 14-5 19-0 24-3 Note b 9-2 14-2 17-11 21-11 25-5
Hem-fir #3 8-7 12-6 15-10 19-5 22-6 7-5 10-10 13-9 16-9 19-6
Southern pine SS 10-3 16-1 21-2 Note b Note b 10-3 16-1 21-2 Note b Note b
Southern pine #1 10-0 15-9 20-10 Note b Note b 10-0 15-9 20-10 25-10 Note b
Southern pine #2 9-10 15-6 20-5 Note b Note b 9-10 15-1 19-5 23-2 Note b
Southern pine #3 9-1 13-6 17-2 20-3 24-1 7-11 11-8 14-10 17-6 20-11
Spruce-pine-fir SS 9-8 15-2 19-11 25-5 Note b 9-8 15-2 19-11 25-5 Note b
Spruce-pine-fir #1 9-5 14-9 19-6 24-10 Note b 9-5 14-4 18-2 22-3 25-9
Spruce-pine-fir #2 9-5 14-9 19-6 24-10 Note b 9-5 14-4 18-2 22-3 25-9
Spruce-pine-fir #3 8-7 12-6 15-10 19-5 22-6 7-5 10-10 13-9 16-9 19-6
16 Douglas fir-larch SS 9-6 14-11 19-7 25-0 Note b 9-6 14-11 19-7 24-9 Note b
Douglas fir-larch #1 9-1 14-4 18-11 23-9 Note b 9-1 13-3 16-10 20-7 23-10
Douglas fir-larch #2 8-11 14-1 18-2 22-3 25-9 8-6 12-5 15-9 19-3 22-4
Douglas fir-larch #3 7-5 10-10 13-9 16-9 19-6 6-5 9-5 11-11 14-6 16-10
Hem-fir SS 8-11 14-1 18-6 23-8 Note b 8-11 14-1 18-6 23-8 Note b
Hem-fir #1 8-9 13-9 18-1 23-1 Note b 8-9 12-11 16-5 20-0 23-3
Hem-fir #2 8-4 13-1 17-3 21-11 25-5 8-4 12-3 15-6 18-11 22-0
Hem-fir #3 7-5 10-10 13-9 16-9 19-6 6-5 9-5 11-11 14-6 16-10
Southern pine SS 9-4 14-7 19-3 24-7 Note b 9-4 14-7 19-3 24-7 Note b
Southern pine #1 9-1 14-4 18-11 24-1 Note b 9-1 14-4 18-10 22-4 Note b
Southern pine #2 8-11 14-1 18-6 23-2 Note b 8-11 13-0 16-10 20-1 23-7
Southern pine #3 7-11 11-8 14-10 17-6 20-11 6-10 10-1 12-10 15-2 18-1
Spruce-pine-fir SS 8-9 13-9 18-1 23-1 Note b 8-9 13-9 18-1 23-0 Note b
Spruce-pine-fir #1 8-7 13-5 17-9 22-3 25-9 8-6 12-5 15-9 19-3 22-4
Spruce-pine-fir #2 8-7 13-5 17-9 22-3 25-9 8-6 12-5 15-9 19-3 22-4
Spruce-pine-fir #3 7-5 10-10 13-9 16-9 19-6 6-5 9-5 11-11 14-6 16-10
19.2 Douglas fir-larch SS 8-11 14-0 18-5 23-7 Note b 8-11 14-0 18-5 22-7 Note b
Douglas fir-larch #1 8-7 13-6 17-9 21-8 25-2 8-4 12-2 15-4 18-9 21-9
Douglas fir-larch #2 8-5 13-1 16-7 20-3 23-6 7-9 11-4 14-4 17-7 20-4
Douglas fir-larch #3 6-9 9-11 12-7 15-4 17-9 5-10 8-7 10-10 13-3 15-5
Hem-fir SS 8-5 13-3 17-5 22-3 Note b 8-5 13-3 17-5 22-3 25-9
Hem-fir #1 8-3 12-11 17-1 21-1 24-6 8-1 11-10 15-0 18-4 21-3
Hem-fir #2 7-10 12-4 16-3 20-0 23-2 7-8 11-2 14-2 17-4 20-1
Hem-fir #3 6-9 9-11 12-7 15-4 17-9 5-10 8-7 10-10 13-3 15-5
Southern pine SS 8-9 13-9 18-1 23-1 Note b 8-9 13-9 18-1 23-1 Note b
Southern pine #1 8-7 13-6 17-9 22-8 Note b 8-7 13-6 17-2 20-5 24-4
Southern pine #2 8-5 13-3 17-5 21-2 24-10 8-4 11-11 15-4 18-4 21-6
Southern pine #3 7-3 10-8 13-7 16-0 19-1 6-3 9-3 11-9 13-10 16-6
Spruce-pine-fir SS 8-3 12-11 17-1 21-9 Note b 8-3 12-11 17-1 21-0 24-4
Spruce-pine-fir #1 8-1 12-8 16-7 20-3 23-6 7-9 11-4 14-4 17-7 20-4
Spruce-pine-fir #2 8-1 12-8 16-7 20-3 23-6 7-9 11-4 14-4 17-7 20-4
Spruce-pine-fir #3 6-9 9-11 12-7 15-4 17-9 5-10 8-7 10-10 13-3 15-5
24 Douglas fir-larch SS 8-3 13-0 17-2 21-10 Note b 8-3 13-0 16-7 20-3 23-5
Douglas fir-larch #1 8-0 12-6 15-10 19-5 22-6 7-5 10-10 13-9 16-9 19-6
Douglas fir-larch #2 7-10 11-9 14-10 18-2 21-0 6-11 10-2 12-10 15-8 18-3
Douglas fir-larch #3 6-1 8-10 11-3 13-8 15-11 5-3 7-8 9-9 11-10 13-9
Hem-fir SS 7-10 12-3 16-2 20-8 25-1 7-10 12-3 16-2 19-10 23-0
Hem-fir #1 7-8 12-0 15-6 18-11 21-11 7-3 10-7 13-5 16-4 19-0
Hem-fir #2 7-3 11-5 14-8 17-10 20-9 6-10 10-0 12-8 15-6 17-11
Hem-fir #3 6-1 8-10 11-3 13-8 15-11 5-3 7-8 9-9 11-10 13-9
Southern pine SS 8-1 12-9 16-10 21-6 Note b 8-1 12-9 16-10 21-6 Note b
Southern pine #1 8-0 12-6 16-6 21-1 25-2 8-0 12-3 15-4 18-3 21-9
Southern pine #2 7-10 12-3 15-10 18-11 22-2 7-5 10-8 13-9 16-5 19-3
Southern pine #3 6-5 9-6 12-1 14-4 17-1 5-7 8-3 10-6 12-5 14-9
Spruce-pine-fir SS 7-8 12-0 15-10 20-2 24-7 7-8 12-0 15-4 18-9 21-9
Spruce-pine-fir #1 7-6 11-9 14-10 18-2 21-0 6-11 10-2 12-10 15-8 18-3
Spruce-pine-fir #2 7-6 11-9 14-10 18-2 21-0 6-11 10-2 12-10 15-8 18-3
Spruce-pine-fir #3 6-1 8-10 11-3 13-8 15-11 5-3 7-8 9-9 11-10 13-9

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. When ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the factors given below:

HC/HR Rafter Span Adjustment Factor
1/3 0.67
1/4 0.76
1/5 0.83
1/6 0.90
1/ 7.5 or less 1.00

where:

HC= Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

HR= Height of roof ridge measured vertically above the top of the rafter support walls.

b. Span exceeds 26 feet in length.

TABLE 802.5.1(3)

RAFTER SPANS FOR COMMON LUMBER SPECIES

(Ground snow load=30 psf, ceiling not attached to rafters, L/ [DELTA] = 180)

RAFTER SPACING (inches) SPECIES AND GRADE DEAD LOAD = 10 psf DEAD LOAD = 20 psf
2 x 4 2 x 6 2 x 8 2 x 10 2 x 12 2 x 4 2 x 6 2 x 8 2 x 10 2 x 12
Maximum rafter spansa
(feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches)
12 Douglas fir-larch SS 10-0 15-9 20-9 Note b Note b 10-0 15-9 20-1 24-6 Note b
Douglas fir-larch #1 9-8 14-9 18-8 22-9 Note b 9-0 13-2 16-8 20-4 23-7
Douglas fir-larch #2 9-5 13-9 17-5 21-4 24-8 8-5 12-4 15-7 19-1 22-1
Douglas fir-larch #3 7-1 10-5 13-2 16-1 18-8 6-4 9-4 11-9 14-5 16-8
Hem-fir SS 9-6 14-10 19-7 25-0 Note b 9-6 14-10 19-7 24-1 Note b
Hem-fir #1 9-3 14-4 18-2 22-2 25-9 8-9 12-10 16-3 19-10 23-0
Hem-fir #2 8-10 13-7 17-2 21-0 24-4 8-4 12-2 15-4 18-9 21-9
Hem-fir #3 7-1 10-5 13-2 16-1 18-8 6-4 9-4 11-9 14-5 16-8
Southern pine SS 9-10 15-6 20-5 Note b Note b 9-10 15-6 20-5 Note Note b
Southern pine #1 9-8 15-2 20-0 24-9 Note b 9-8 14-10 18-8 b 22-2 Note b
Southern pine #2 9-6 14-5 18-8 22-3 Note b 9-0 12-11 16-8 19-11 23-4
Southern pine #3 7-7 11-2 14-3 16-10 20-0 6-9 10-0 12-9 15-1 17-11
Spruce-pine-fir SS 9-3 14-7 19-2 24-6 Note b 9-3 14-7 18-8 22-9 Note b
Spruce-pine-fir #1 9-1 13-9 17-5 21-4 24-8 8-5 12-4 15-7 19-1 22-1
Spruce-pine-fir #2 9-1 13-9 17-5 21-4 24-8 8-5 12-4 15-7 19-1 22-1
Spruce-pine-fir #3 7-1 10-5 13-2 16-1 18-8 6-4 9-4 11-9 14-5 16-8
16 Douglas fir-larch SS 9-1 14-4 18-10 23-9 Note b 9-1 13-9 17-5 21-3 24-8
Douglas fir-larch #1 8-9 12-9 16-2 19-9 22-10 7-10 11-5 14-5 17-8 20-5
Douglas fir-larch #2 8-2 11-11 15-1 18-5 21-5 7-3 10-8 13-6 16-6 19-2
Douglas fir-larch #3 6-2 9-0 11-5 13-11 16-2 5-6 8-1 10-3 12-6 14-6
Hem-fir SS 8-7 13-6 17-10 22-9 Note b 8-7 13-6 17-1 20-10 24-2
Hem-fir #1 8-5 12-5 15-9 19-3 22-3 7-7 11-1 14-1 17-2 19-11
Hem-fir #2 8-0 11-9 14-11 18-2 21-1 7-2 10-6 13-4 16-3 18-10
Hem-fir #3 6-2 9-0 11-5 13-11 16-2 5-6 8-1 10-3 12-6 14-6
Southern pine SS 8-11 14-1 18-6 23-8 Note b 8-11 14-1 18-6 23-8 Note b
Southern pine #1 8-9 13-9 18-1 21-5 25-7 8-8 12-10 16-2 19-2 22-10
Southern pine #2 8-7 12-6 16-2 19-3 22-7 7-10 11-2 14-5 17-3 20-2
Southern pine #3 6-7 9-8 12-4 14-7 17-4 5-10 8-8 11-0 13-0 15-6
Spruce-pine-fir SS 8-5 13-3 17-5 22-1 25-7 8-5 12-9 16-2 19-9 22-10
Spruce-pine-fir #1 8-2 11-11 15-1 18-5 21-5 7-3 10-8 13-6 16-6 19-2
Spruce-pine-fir #2 8-2 11-11 15-1 18-5 21-5 7-3 10-8 13-6 16-6 19-2
Spruce-pine-fir #3 6-2 9-0 11-5 13-11 16-2 5-6 8-1 10-3 12-6 14-6
19.2 Douglas fir-larch SS 8-7 13-6 17-9 21-8 25-2 8-7 12-6 15-10 19-5 22-6
Douglas fir-larch #1 7-11 11-8 14-9 18-0 20-11 7-1 10-5 13-2 16-1 18-8
Douglas fir-larch #2 7-5 10-11 13-9 16-10 19-6 6-8 9-9 12-4 15-1 17-6
Douglas fir-larch #3 5-7 8-3 10-5 12-9 14-9 5-0 7-4 9-4 11-5 13-2
Hem-fir SS 8-1 12-9 16-9 21-4 24-8 8-1 12-4 15-7 19-1 22-1
Hem-fir #1 7-9 11-4 14-4 17-7 20-4 6-11 10-2 12-10 15-8 18-2
Hem-fir #2 7-4 10-9 13-7 16-7 19-3 6-7 9-7 12-2 14-10 17-3
Hem-fir #3 5-7 8-3 10-5 12-9 14-9 5-0 7-4 9-4 11-5 13-2
Southern pine SS 8-5 13-3 17-5 22-3 Note b 8-5 13-3 17-5 22-0 25-9
Southern pine #1 8-3 13-0 16-6 19-7 23-4 7-11 11-9 14-9 17-6 20-11
Southern pine #2 7-11 11-5 14-9 17-7 20-7 7-1 10-2 13-2 15-9 18-5
Southern pine #3 6-0 8-10 11-3 13-4 15-10 5-4 7-11 10-1 11-11 14-2
Spruce-pine-fir SS 7-11 12-5 16-5 20-2 23-4 7-11 11-8 14-9 18-0 20-11
Spruce-pine-fir #1 7-5 10-11 13-9 16-10 19-6 6-8 9-9 12-4 15-1 17-6
Spruce-pine-fir #2 7-5 10-11 13-9 16-10 19-6 6-8 9-9 12-4 15-1 17-6
Spruce-pine-fir #3 5-7 8-3 10-5 12-9 14-9 5-0 7-4 9-4 11-5 13-2
24 Douglas fir-larch SS 7-11 12-6 15-10 19-5 22-6 7-8 11-3 14-2 17-4 20-1
Douglas fir-larch #1 7-1 10-5 13-2 16-1 18-8 6-4 9-4 11-9 14-5 16-8
Douglas fir-larch #2 6-8 9-9 12-4 15-1 17-6 5-11 8-8 11-0 13-6 15-7
Douglas fir-larch #3 5-0 7-4 9-4 11-5 13-2 4-6 6-7 8-4 10-2 11-10
Hem-fir SS 7-6 11-10 15-7 19-1 22-1 7-6 11-0 13-11 17-0 19-9
Hem-fir #1 6-11 10-2 12-10 15-8 18-2 6-2 9-1 11-6 14-0 16-3
Hem-fir #2 6-7 9-7 12-2 14-10 17-3 5-10 8-7 10-10 13-3 15-5
Hem-fir #3 5-0 7-4 9-4 11-5 13-2 4-6 6-7 8-4 10-2 11-10
Southern pine SS 7-10 12-3 16-2 20-8 25-1 7-10 12-3 16-2 19-8 23-0
Southern pine #1 7-8 11-9 14-9 17-6 20-11 7-1 10-6 13-2 15-8 18-8
Southern pine #2 7-1 10-2 13-2 15-9 18-5 6-4 9-2 11-9 14-1 16-6
Southern pine #3 5-4 7-11 10-1 11-11 14-2 4-9 7-1 9-0 10-8 12-8
Spruce-pine-fir SS 7-4 11-7 14-9 18-0 20-11 7-1 10-5 13-2 16-1 18-8
Spruce-pine-fir #1 6-8 9-9 12-4 15-1 17-6 5-11 8-8 11-0 13-6 15-7
Spruce-pine-fir #2 6-8 9-9 12-4 15-1 17-6 5-11 8-8 11-0 13-6 15-7
Spruce-pine-fir #3 5-0 7-4 9-4 11-5 13-2 4-6 6-7 8-4 10-2 11-10

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. When ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the factors given below:

HC/HR Rafter Span Adjustment Factor
1/3 0.67
1/4 0.76
1/5 0.83
1/6 0.90
1/ 7.5 or less 1.00

where:

HC= Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

HR= Height of roof ridge measured vertically above the top of the rafter support walls.

b. Span exceeds 26 feet in length.

TABLE 802.5.1(4)

RAFTER SPANS FOR COMMON LUMBER SPECIES

(Ground snow load=50 psf, ceiling not attached to rafters, L/[DELTA] = 180)

RAFTER SPACING (inches) SPECIES AND GRADE DEAD LOAD = 10 psf DEAD LOAD = 20 psf
2 x 4 2 x 6 2 x 8 2 x 10 2 x 12 2 x 4 2 x 6 2 x 8 2 x 10 2 x 12
Maximum rafter spansa
(feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches)
12 Douglas fir-larch SS 8-5 13-3 17-6 22-4 26-0 8-5 13-3 17-0 20-9 24-0
Douglas fir-larch #1 8-2 12-0 15-3 18-7 21-7 7-7 11-2 14-1 17-3 20-0
Douglas fir-larch #2 7-8 11-3 14-3 17-5 20-2 7-1 10-5 13-2 16-1 18-8
Douglas fir-larch #3 5-10 8-6 10-9 13-2 15-3 5-5 7-10 10-0 12-2 14-1
Hem-fir SS 8-0 12-6 16-6 21-1 25-6 8-0 12-6 16-6 20-4 23-7
Hem-fir #1 7-10 11-9 14-10 18-1 21-0 7-5 10-10 13-9 16-9 19-5
Hem-fir #2 7-5 11-1 14-0 17-2 19-11 7-0 10-3 13-0 15-10 18-5
Hem-fir #3 5-10 8-6 10-9 13-2 15-3 5-5 7-10 10-0 12-2 14-1
Southern pine SS 8-4 13-0 17-2 21-11 Note b 8-4 13-0 17-2 21-11 Note b
Southern pine #1 8-2 12-10 16-10 20-3 24-1 8-2 12-6 15-9 18-9 22-4
Southern pine #2 8-0 11-9 15-3 18-2 21-3 7-7 10-11 14-1 16-10 19-9
Southern pine #3 6-2 9-2 11-8 13-9 16-4 5-9 8-5 10-9 12-9 15-2
Spruce-pine-fir SS 7-10 12-3 16-2 20-8 24-1 7-10 12-3 15-9 19-3 22-4
Spruce-pine-fir #1 7-8 11-3 14-3 17-5 20-2 7-1 10-5 13-2 16-1 18-8
Spruce-pine-fir #2 7-8 11-3 14-3 17-5 20-2 7-1 10-5 13-2 16-1 18-8
Spruce-pine-fir #3 5-10 8-6 10-9 13-2 15-3 5-5 7-10 10-0 12-2 14-1
16 Douglas fir-larch SS 7-8 12-1 15-10 19-5 22-6 7-8 11-7 14-8 17-11 20-10
Douglas fir-larch #1 7-1 10-5 13-2 16-1 18-8 6-7 9-8 12-2 14-11 17-3
Douglas fir-larch #2 6-8 9-9 12-4 15-1 17-6 6-2 9-0 11-5 13-11 16-2
Douglas fir-larch #3 5-0 7-4 9-4 11-5 13-2 4-8 6-10 8-8 10-6 12-3
Hem-fir SS 7-3 11-5 15-0 19-1 22-1 7-3 11-5 14-5 17-8 20-5
Hem-fir #1 6-11 10-2 12-10 15-8 18-2 6-5 9-5 11-11 14-6 16-10
Hem-fir #2 6-7 9-7 12-2 14-10 17-3 6-1 8-11 11-3 13-9 15-11
Hem-fir #3 5-0 7-4 9-4 11-5 13-2 4-8 6-10 8-8 10-6 12-3
Southern pine SS 7-6 11-10 15-7 19-11 24-3 7-6 11-10 15-7 19-11 23-10
Southern pine #1 7-5 11-7 14-9 17-6 20-11 7-4 10-10 13-8 16-2 19-4
Southern pine #2 7-1 10-2 13-2 15-9 18-5 6-7 9-5 12-2 14-7 17-1
Southern pine #3 5-4 7-11 10-1 11-11 14-2 4-11 7-4 9-4 11-0 13-1
Spruce-pine-fir SS 7-1 11-2 14-8 18-0 20-11 7-1 10-9 13-8 15-11 19-4
Spruce-pine-fir #1 6-8 9-9 12-4 15-1 17-6 6-2 9-0 11-5 13-11 16-2
Spruce-pine-fir #2 6-8 9-9 12-4 15-1 17-6 6-2 9-0 11-5 13-11 16-2
Spruce-pine-fir #3 5-0 7-4 9-4 11-5 13-2 4-8 6-10 8-8 10-6 12-3
19.2 Douglas fir-larch SS 7-3 11-4 14-6 17-8 20-6 7-3 10-7 13-5 16-5 19-0
Douglas fir-larch #1 6-6 9-6 12-0 14-8 17-1 6-0 8-10 11-2 13-7 15-9
Douglas fir-larch #2 6-1 8-11 11-3 13-9 15-11 5-7 8-3 10-5 12-9 14-9
Douglas fir-larch #3 4-7 6-9 8-6 10-5 12-1 4-3 6-3 7-11 9-7 11-2
Hem-fir SS 6-10 10-9 14-2 17-5 20-2 6-10 10-5 13-2 16-1 18-8
Hem-fir #1 6-4 9-3 11-9 14-4 16-7 5-10 8-7 10-10 13-3 15-5
Hem-fir #2 6-0 8-9 11-1 13-7 15-9 5-7 8-1 10-3 12-7 14-7
Hem-fir #3 4-7 6-9 8-6 10-5 12-1 4-3 6-3 7-11 9-7 11-2
Southern pine SS 7-1 11-2 14-8 18-9 22-10 7-1 11-2 14-8 18 7 21-9
Southern pine #1 7-0 10-8 13-5 16-0 19-1 6-8 9-11 12-5 14-10 17-8
Southern pine #2 6-6 9-4 12-0 14-4 16-10 6-0 8-8 11-2 13-4 15-7
Southern pine #3 4-11 7-3 9-2 10-10 12-11 4-6 6-8 8-6 10-1 12-0
Spruce-pine-fir SS 6-8 10-6 13-5 16-5 19-1 6-8 9-10 12-5 15-3 17-8
Spruce-pine-fir #1 6-1 8-11 11-3 13-9 15-11 5-7 8-3 10-5 12-9 14-9
Spruce-pine-fir #2 6-1 8-11 11-3 13-9 15-11 5-7 8-3 10-5 12-9 14-9
Spruce-pine-fir #3 4-7 6-9 8-6 10-5 12-1 4-3 6-3 7-11 9-7 11-2
24 Douglas fir-larch SS 6-8 10 13-0 15-10 18-4 6-6 9-6 12-0 14-8 17-0
Douglas fir-larch #1 5-10 8-6 10-9 13-2 15-3 5-5 7-10 10-0 12-2 14-1
Douglas fir-larch #2 5-5 7-11 10-1 12-4 14-3 5-0 7-4 9-4 11-5 13-2
Douglas fir-larch #3 4-1 6-0 7-7 9-4 10-9 3-10 5-7 7-1 8-7 10-0
Hem-fir SS 6-4 9-11 12-9 15-7 18-0 6-4 9-4 11-9 14-5 16-8
Hem-fir #1 5-8 8-3 10-6 12-10 14-10 5-3 7-8 9-9 11-10 13-9
Hem-fir #2 5-4 7-10 9-11 12-1 14-1 4-11 7-3 9-2 11-3 13-0
Hem-fir #3 4-1 6-0 7-7 9-4 10-9 3-10 5-7 7-1 8-7 10-0
Southern pine SS 6-7 10-4 13-8 17-5 21-0 6-7 10-4 13-8 16-7 19-5
Southern pine #1 6-5 9-7 12-0 14-4 17-1 6-0 8-10 11-2 13-3 15-9
Southern pine #2 5-10 8-4 10-9 12-10 15-1 5-5 7-9 10-0 11-11 13-11
Southern pine #3 4-4 6-5 8-3 9-9 11-7 4-1 6-0 7-7 9-0 10-8
Spruce-pine-fir SS 6-2 9-6 12-0 14-8 17-1 6-0 8-10 11-2 13-7 15-9
Spruce-pine-fir #1 5-5 7-11 10-1 12-4 14-3 5-0 7-4 9-4 11-5 13-2
Spruce-pine-fir #2 5-5 7-11 10-1 12-4 14-3 5-0 7-4 9-4 11-5 13-2
Spruce-pine-fir #3 4-1 6-0 7-7 9-4 10-9 3-10 5-7 7-1 8-7 10-0

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. When ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the factors given below:

HC/HR Rafter Span Adjustment Factor
1/3 0.67
1/4 0.76
1/5 0.83
1/6 0.90
1/ 7.5 or less 1.00

where:

HC= Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

HR= Height of roof ridge measured vertically above the top of the rafter support walls.

b. Span exceeds 26 feet in length.

TABLE 802.5.1(5)

RAFTER SPANS FOR COMMON LUMBER SPECIES

(Ground snow load=30 psf, ceiling attached to rafters, L/[DELTA]S = 240)

RAFTER SPACING (inches) SPECIES AND GRADE DEAD LOAD = 10 psf DEAD LOAD = 20 psf
2 x 4 2 x 6 2 x 8 2 x 10 2 x 12 2 x 4 2 x 6 2 x 8 2 x 10 2 x 12
Maximum rafter spansa
(feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches)
12 Douglas fir-larch SS 9-1 14-4 18-10 24-1 Note b 9-1 14-4 18-10 24-1 Note b
Douglas fir-larch #1 8-9 13-9 18-2 22-9 Note b 8-9 13-2 16-8 20-4 23-7
Douglas fir-larch #2 8-7 13-6 17-5 21-4 24-8 8-5 12-4 15-7 19-1 22-1
Douglas fir-larch #3 7-1 10-5 13-2 16-1 18-8 6-4 9-4 11-9 14-5 16-8
Hem-fir SS 8-7 13-6 17-10 22-9 Note b 8-7 13-6 17-10 22-9 Note b
Hem-fir #1 8-5 13-3 17-5 22-2 25-9 8-5 12-10 16-3 19-10 23-0
Hem-fir #2 8-0 12-7 16-7 21-0 24-4 8-0 12-2 15-4 18-9 21-9
Hem-fir #3 7-1 10-5 13-2 16-1 18-8 6-4 9-4 11-9 14-5 16-8
Southern pine SS 8-11 14-1 18-6 23-8 Note b 8-11 14-1 18-6 23-8 Note b
Southern pine #1 8-9 13-9 18-2 23-2 Note b 8-9 13-9 18-2 22-2 Note b
Southern pine #2 8-7 13-6 17-10 22-3 Note b 8-7 12-11 16-8 19-11 23-4
Southern pine #3 7-7 11-2 14-3 16-10 20-0 6-9 10-0 12-9 15-1 17-11
Spruce-pine-fir SS 8-5 13-3 17-5 22-3 Note b 8-5 13-3 17-5 22-3 Note b
Spruce-pine-fir #1 8-3 12-11 17-0 21-4 24-8 8-3 12-4 15-7 19-1 22-1
Spruce-pine-fir #2 8-3 12-11 17-0 21-4 24-8 8-3 12-4 15-7 19-1 22-1
Spruce-pine-fir #3 7-1 10-5 13-2 16-1 18-8 6-4 9-4 11-9 14-5 16-8
16 Douglas fir-larch SS 8-3 13-0 17-2 21-10 Note b 8-3 13-0 17-2 21-3 24-8
Douglas fir-larch #1 8-0 12-6 16-2 19-9 22-10 7-10 11-5 14-5 17-8 20-5
Douglas fir-larch #2 7-10 11-11 15-1 18-5 21-5 7-3 10-8 13-6 16-6 19-2
Douglas fir-larch #3 6-2 9-0 11-5 13-11 16-2 5-6 8-1 10-3 12-6 14-6
Hem-fir SS 7-10 12-3 16-2 20-8 25-1 7-10 12-3 16-2 20-8 24-2
Hem-fir #1 7-8 12-0 15-9 19-3 22-3 7-7 11-1 14-1 17-2 19-11
Hem-fir #2 7-3 11-5 14-11 18-2 21-1 7-2 10-6 13-4 16-3 18-10
Hem-fir #3 6-2 9-0 11-5 13-11 16-2 5-6 8-1 10-3 12-6 14-6
Southern pine SS 8-1 12-9 16-10 21-6 Note b 8-1 12-9 16-10 21-6 Note b
Southern pine #1 8-0 12-6 16-6 21-1 25-7 8-0 12-6 16-2 19-2 22-10
Southern pine #2 7-10 12-3 16-2 19-3 22-7 7-10 11-2 14-5 17-3 20-2
Southern pine #3 6-7 9-8 12-4 14-7 17-4 5-10 8-8 11-0 13-0 15-6
Spruce-pine-fir SS 7-8 12-0 15-10 20-2 24-7 7-8 12-0 15-10 19-9 22-10
Spruce-pine-fir #1 7-6 11-9 15-1 18-5 21-5 7-3 10-8 13-6 16-6 19-2
Spruce-pine-fir #2 7-6 11-9 15-1 18-5 21-5 7-3 10-8 13-6 16-6 19-2
Spruce-pine-fir #3 6-2 9-0 11-5 13-11 16-2 5-6 8-1 10-3 12-6 14-6
19.2 Douglas fir-larch SS 7-9 12-3 16-1 20-7 25-0 7-9 12-3 15-10 19-5 22-6
Douglas fir-larch #1 7-6 11-8 14-9 18-0 20-11 7-1 10-5 13-2 16-1 18-8
Douglas fir-larch #2 7-4 10-11 13-9 16-10 19-6 6-8 9-9 12-4 15-1 17-6
Douglas fir-larch #3 5-7 8-3 10-5 12-9 14-9 5-0 7-4 9-4 11-5 13-2
Hem-fir SS 7-4 11-7 15-3 19-5 23-7 7-4 11-7 15-3 19-1 22-1
Hem-fir #1 7-2 11-4 14-4 17-7 20-4 6-11 10-2 12-10 15-8 18-2
Hem-fir #2 6-10 10-9 13-7 16-7 19-3 6-7 9-7 12-2 14-10 17-3
Hem-fir #3 5-7 8-3 10-5 12-9 14-9 5-0 7-4 9-4 11-5 13-2
Southern pine SS 7-8 12-0 15-10 20-2 24-7 7-8 12-0 15-10 20-2 24-7
Southern pine #1 7-6 11-9 15-6 19-7 23-4 7-6 11-9 14-9 17-6 20-11
Southern pine #2 7-4 11-5 14-9 17-7 20-7 7-1 10-2 13-2 15-9 18-5
Southern pine #3 6-0 8-10 11-3 13-4 15-10 5-4 7-11 10-1 11-11 14-2
Spruce-pine-fir SS 7-2 11-4 14-11 19-0 23-1 7-2 11-4 14-9 18-0 20-11
Spruce-pine-fir #1 7-0 10-11 13-9 16-10 19-6 6-8 9-9 12-4 15-1 17-6
Spruce-pine-fir #2 7-0 10-11 13-9 16-10 19-6 6-8 9-9 12-4 15-1 17-6
Spruce-pine-fir #3 5-7 8-3 10-5 12-9 14-9 5-0 7-4 9-4 11-5 13-2
24 Douglas fir-larch SS 7-3 11-4 15-0 19-1 22-6 7-3 11-3 14-2 17-4 20-1
Douglas fir-larch #1 7-0 10-5 13-2 16-1 18-8 6-4 9-4 11-9 14-5 16-8
Douglas fir-larch #2 6-8 9-9 12-4 15-1 17-6 5-11 8-8 11-0 13-6 15-7
Douglas fir-larch #3 5-0 7-4 9-4 11-5 13-2 4-6 6-7 8-4 10-2 11-10
Hem-fir SS 6-10 10-9 14-2 18-0 21-11 6-10 10-9 13-11 17-0 19-9
Hem-fir #1 6-8 10-2 12-10 15-8 18-2 6-2 9-1 11-6 14-0 16-3
Hem-fir #2 6-4 9-7 12-2 14-10 17-3 5-10 8-7 10-10 13-3 15-5
Hem-fir #3 5-0 7-4 9-4 11-5 13-2 4-6 6-7 8-4 10-2 11-10
Southern pine SS 7-1 11-2 14-8 18-9 22-10 7-1 11-2 14-8 18-9 22-10
Southern pine #1 7-0 10-11 14-5 17-6 20-11 7-0 10-6 13-2 15-8 18-8
Southern pine #2 6-10 10-2 13-2 15-9 18-5 6-4 9-2 11-9 14-1 16-6
Southern pine #3 5-4 7-11 10-1 11-11 14-2 4-9 7-1 9-0 10-8 12-8
Spruce-pine-fir SS 6-8 10-6 13-10 17-8 20-11 6-8 10-5 13-2 16-1 18-8
Spruce-pine-fir #1 6-6 9-9 12-4 15-1 17-6 5-11 8-8 11-0 13-6 15-7
Spruce-pine-fir #2 6-6 9-9 12-4 15-1 17-6 5-11 8-8 11-0 13-6 15-7
Spruce-pine-fir #3 5-0 7-4 9-4 11-5 13-2 4-6 6-7 8-4 10-2 11-10

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. When ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the factors given below:

HC/HR Rafter Span Adjustment Factor
1/3 0.67
1/4 0.76
1/5 0.83
1/6 0.90
1/ 7.5 or less 1.00

where:

Hc = Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

HR = Height of roof ridge measured vertically above the top of the rafter support walls.

b. Span exceeds 26 feet in length.

TABLE 802.5.1(6) RAFTER SPANS FOR COMMON LUMBER SPECIES

(Ground snow load=50 psf, ceiling attached to rafters, L/[DELTA] = 240)

RAFTER SPACING (inches) SPECIES AND GRADE DEAD LOAD = 10 psf DEAD LOAD = 20 psf
2 x 4 2 x 6 2 x 8 2 x 10 2 x 12 2 x 4 2 x 6 2 x 8 2 x 10 2 x 12
Maximum rafter spansa
(feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches)
12 Douglas fir-larch SS 7-8 12-1 15-11 20-3 24-8 7-8 12-1 15-11 20-3 24-0
Douglas fir-larch #1 7-5 11-7 15-3 18-7 21-7 7-5 11-2 14-1 17-3 20-0
Douglas fir-larch #2 7-3 11-3 14-3 17-5 20-2 7-1 10-5 13-2 16-1 18-8
Douglas fir-larch #3 5-10 8-6 10-9 13-2 15-3 5-5 7-10 10-0 12-2 14-1
Hem-fir SS 7-3 11-5 15-0 19-2 23-4 7-3 11-5 15-0 19-2 23-4
Hem-fir #1 7-1 11-2 14-8 18-1 21-0 7-1 10-10 13-9 16-9 19-5
Hem-fir #2 6-9 10-8 14-0 17-2 19-11 6-9 10-3 13-0 15-10 18-5
Hem-fir #3 5-10 8-6 10-9 13-2 15-3 5-5 7-10 10-0 12-2 14-1
Southern pme SS 7-6 11-10 15-7 19-11 24-3 7-6 11-10 15-7 19-11 24-3
Southern pme #1 7-5 11-7 15-4 19-7 23-9 7-5 11-7 15-4 18-9 22-4
Southern pme #2 7-3 11-5 15-0 18-2 21-3 7-3 10-11 14-1 16-10 19-9
Southern pme #3 6-2 9-2 11-8 13-9 16-4 5-9 8-5 10-9 12-9 15-2
Spruce-pme-frr SS 7-1 11-2 14-8 18-9 22-10 7-1 11-2 14-8 18-9 22-4
Spruce-pme-frr #1 6-11 10-11 14-3 17-5 20-2 6-11 10-5 13-2 16-1 18-8
Spruce-pme-frr #2 6-11 10-11 14-3 17-5 20-2 6-11 10-5 13-2 16-1 18-8
Spruce-pme-fir #3 5-10 8-6 10-9 13-2 15-3 5-5 7-10 10-0 12-2 14-1
16 Douglas fir-larch SS 7-0 11-0 14-5 18-5 22-5 7-0 11-0 14-5 17-11 20-10
Douglas fir-larch #1 6-9 10-5 13-2 16-1 18-8 6-7 9-8 12-2 14-11 17-3
Douglas fir-larch #2 6-7 9-9 12-4 15-1 17-6 6-2 9-0 11-5 13-11 16-2
Douglas fir-larch #3 5-0 7-4 9-4 11-5 13-2 4-8 6-10 8-8 10-6 12-3
Hem-fir SS 6-7 10-4 13-8 17-5 21-2 6-7 10-4 13-8 17-5 20-5
Hem-fir #1 6-5 10-2 12-10 15-8 18-2 6-5 9-5 11-11 14-6 16-10
Hem-fir #2 6-2 9-7 12-2 14-10 17-3 6-1 8-11 11-3 13-9 15-11
Hem-fir #3 5-0 7-4 9-4 11-5 13-2 4-8 6-10 8-8 10-6 12-3
Southern pine SS 6-10 10-9 14-2 18-1 22-0 6-10 10-9 14-2 18-1 22-0
Southern pine #1 6-9 10-7 13-11 17-6 20-11 6-9 10-7 13-8 16-2 19-4
Southern pine #2 6-7 10-2 13-2 15-9 18-5 6-7 9-5 12-2 14-7 17-1
Southern pine #3 5-4 7-11 10-1 11-11 14-2 4-11 7-4 9-4 11-0 13-1
Spruce-pine-fir SS 6-5 10-2 13-4 17-0 20-9 6-5 10-2 13-4 16-8 19-4
Spruce-pine-fir #1 6-4 9-9 12-4 15-1 17-6 6-2 9-0 11-5 13-11 16-2
Spruce-pine-fir #2 6-4 9-9 12-4 15-1 17-6 6-2 9-0 11-5 13-11 16-2
Spruce-pine-fir #3 5-0 7-4 9-4 11-5 13-2 4-8 6-10 8-8 10-6 12-3
19.2 Douglas fir-larch SS 6-7 10-4 13-7 17-4 20-6 6-7 10-4 13-5 16-5 19-0
Douglas fir-larch #1 6-4 9-6 12-0 14-8 17-1 6-0 8-10 11-2 13-7 15-9
Douglas fir-larch #2 6-1 8-11 11-3 13-9 15-11 5-7 8-3 10-5 12-9 14-9
Douglas fir-larch #3 4-7 6-9 8-6 10-5 12-1 4-3 6-3 7-11 9-7 11-2
Hem-fir SS 6-2 9-9 12-10 16-5 19-11 6-2 9-9 12-10 16-1 18-8
Hem-fir #1 6-1 9-3 11-9 14-4 16-7 5-10 8-7 10-10 13-3 15-5
Hem-fir #2 5-9 8-9 11-1 13-7 15-9 5-7 8-1 10-3 12-7 14-7
Hem-fir #3 4-7 6-9 8-6 10-5 12-1 4-3 6-3 7-11 9-7 11-2
Southern pine SS 6-5 10-2 13-4 17-0 20-9 6-5 10-2 13-4 17-0 20-9
Southern pine #1 6-4 9-11 13-1 16-0 19-1 6-4 9-11 12-5 14-10 17-8
Southern pine #2 6-2 9-4 12-0 14-4 16-10 6-0 8-8 11-2 13-4 15-7
Southern pine #3 4-11 7-3 9-2 10-10 12-11 4-6 6-8 8-6 10-1 12-0
Spruce-pine-fir SS 6-1 9-6 12-7 16-0 19-1 6-1 9-6 12-5 15-3 17-8
Spruce-pine-fir #1 5-11 8-11 11-3 13-9 15-11 5-7 8-3 10-5 12-9 14-9
Spruce-pine-fir #2 5-11 8-11 11-3 13-9 15-11 5-7 8-3 10-5 12-9 14-9
Spruce-pine-fir #3 4-7 6-9 8-6 10-5 12-1 4-3 6-3 7-11 9-7 11-2
24 Douglas fir-larch SS 6-1 9-7 12-7 15-10 18-4 6-1 9-6 12-0 14-8 17-0
Douglas fir-larch #1 5-10 8-6 10-9 13-2 15-3 5-5 7-10 10-0 12-2 14-1
Douglas fir-larch #2 5-5 7-11 10-1 12-4 14-3 5-0 7-4 9-4 11-5 13-2
Douglas fir-larch #3 4-1 6-0 7-7 9-4 10-9 3-10 5-7 7-1 8-7 10-0
Hem-fir SS 5-9 9-1 11-11 15-2 18-0 5-9 9-1 11-9 14-5 15-11
Hem-fir #1 5-8 8-3 10-6 12-10 14-10 5-3 7-8 9-9 11-10 13-9
Hem-fir #2 5-4 7-10 9-11 12-1 14-1 4-11 7-3 9-2 11-3 13-0
Hem-fir #3 4-1 6-0 7-7 9-4 10-9 3-10 5-7 7-1 8-7 10-0
Southern pine SS 6-0 9-5 12-5 15-10 19-3 6-0 9-5 12-5 15-10 19-3
Southern pine #1 5-10 9-3 12-0 14-4 17-1 5-10 8-10 11-2 13-3 15-9
Southern pine #2 5-9 8-4 10-9 12-10 15-1 5-5 7-9 10-0 11-11 13-11
Southern pine #3 4-4 6-5 8-3 9-9 11-7 4-1 6-0 7-7 9-0 10-8
Spruce-pine-fir SS 5-8 8-10 11-8 14-8 17-1 5-8 8-10 11-2 13-7 15-9
Spruce-pine-fir #1 5-5 7-11 10-1 12-4 14-3 5-0 7-4 9-4 11-5 13-2
Spruce-pine-fir #2 5-5 7-11 10-1 12-4 14-3 5-0 7-4 9-4 11-5 13-2
Spruce-pine-fir #3 4-1 6-0 7-7 9-4 10-9 3-10 5-7 7-1 8-7 10-0

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location.

When ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the factors given below:

HC/HR Rafter Span Adjustment Factor
1/3 0.67
1/4 0.76
1/5 0.83
1/6 0.90
1/ 7.5 or less 1.00

where:

HC= Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

HR= Height of roof ridge measured vertically above the top of the rafter support walls.

TABLE 802.5.1(7)

RAFTER SPANS FOR 70 PSF GROUND SNOW LOAD

(Ceiling not attached to rafters, L/[DELTA] = 180)

RAFTER SPACING (inches) SPECIES AND GRADE DEAD LOAD = 10 psf DEAD LOAD = 20 psf
2 x 4 2 x 6 2 x 8 2 x 10 2 x 12 2 x 4 2 x 6 2 x 8 2 x 10 2 x 12
Maximum rafter spansa
(feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches)
12 Douglas fir-larch SS 7-7 11-10 15-8 19-5 22-6 7-7 11-10 15-0 18-3 21-2
Douglas fir-larch #1 7-1 10-5 13-2 16-1 18-8 6-8 9-10 12-5 15-2 17-7
Douglas fir-larch #2 6-8 9-9 12-4 15-1 17-6 6-3 9-2 11-8 14-2 16-6
Douglas fir-larch #3 5-0 7-4 9-4 11-5 13-2 4-9 6-11 8-9 10-9 12-5
Hem-fir SS 7-2 11-3 14-9 18-10 22-1 7-2 11-3 14-8 18-0 20-10
Hem-fir #1 6-11 10-2 12-10 15-8 18-2 6-6 9-7 12-1 14-10 17-2
Hem-fir #2 6-7 9-7 12-2 14-10 17-3 6-2 9-1 11-5 14-0 16-3
Hem-fir #3 5-0 7-4 9-4 11-5 13-2 4-9 6-11 8-9 10-9 12-5
Southern pine SS 7-5 11-8 15-4 19-7 23-10 7-5 11-8 15-4 19-7 23-10
Southern pine #1 7-3 11-5 14-9 17-6 20-11 7-3 11-1 13-11 16-6 19-8
Southern pine #2 7-1 10-2 13-2 15-9 18-5 6-8 9-7 12-5 14-10 17-5
Southern pine #3 5-4 7-11 10-1 11-11 14-2 5-1 7-5 9-6 11-3 13-4
Spruce-pine-fir SS 7-0 11-0 14-6 18-0 20-11 7-0 11-0 13-11 17-0 19-8
Spruce-pine-fir #1 6-8 9-9 12-4 15-1 17-6 6-3 9-2 11-8 14-2 16-6
Spruce-pine-fir #2 6-8 9-9 12-4 15-1 17-6 6-3 9-2 11-8 14-2 16-6
Spruce-pine-fir #3 5-0 7-4 9-4 11-5 13-2 4-9 6-11 8-9 10-9 12-5
16 Douglas fir-larch SS 6-10 10-9 13-9 16-10 19-6 6-10 10-3 13-0 15-10 18-4
Douglas fir-larch #1 6-2 9-0 11-5 13-11 16-2 5-10 8-6 10-9 13-2 15-3
Douglas fir-larch #2 5-9 8-5 10-8 13-1 15-2 5-5 7-11 10-1 12-4 14-3
Douglas fir-larch #3 4-4 6-4 8-1 9-10 11-5 4-1 6-0 7-7 9-4 10-9
Hem-fir SS 6-6 10-2 13-5 16-6 19-2 6-6 10-1 12-9 15-7 18-0
Hem-fir #1 6-0 8-9 11-2 13-7 15-9 5-8 8-3 10-6 12-10 14-10
Hem-fir #2 5-8 8-4 10-6 12-10 14-11 5-4 7-10 9-11 12-1 14-1
Hem-fir #3 4-4 6-4 8-1 9-10 11-5 4-1 6-0 7-7 9-4 10-9
Southern pine SS 6-9 10-7 14-0 17-10 21-8 6-9 10-7 14-0 17-10 21-0
Southern pine #1 6-7 10-2 12-9 15-2 18-1 6-5 9-7 12-0 14-4 17-1
Southern pine #2 6-2 8-10 11-5 13-7 16-0 5-10 8-4 10-9 12-10 15-1
Southern pine #3 4-8 6-10 8-9 10-4 12-3 4-4 6-5 8-3 9-9 11-7
Spruce-pine-fir SS 6-4 10-0 12-9 15-7 18-1 6-4 9-6 12-0 14-8 17-1
Spruce-pine-fir #1 5-9 8-5 10-8 13-1 15-2 5-5 7-11 10-1 12-4 14-3
Spruce-pine-fir #2 5-9 8-5 10-8 13-1 15-2 5-5 7-11 10-1 12-4 14-3
Spruce-pine-fir #3 4-4 6-4 8-1 9-10 11-5 4-1 6-0 7-7 9-4 10-9
19.2 Douglas fir-larch SS 6-5 9-11 12-7 15-4 17-9 6-5 9-4 11-10 14-5 16-9
Douglas fir-larch #1 5-7 8-3 10-5 12-9 14-9 5-4 7-9 9-10 12-0 13-11
Douglas fir-larch #2 5-3 7-8 9-9 11-11 13-10 5-0 7-3 9-2 11-3 13-0
Douglas fir-larch #3 4-0 5-10 7-4 9-0 10-5 3-9 5-6 6-11 8-6 9-10
Hem-fir SS 6-1 9-7 12-4 15-1 17-4 6-1 9-2 11-8 14-2 15-5
Hem-fir #1 5-6 8-0 10-2 12-5 14-5 5-2 7-7 9-7 11-8 13-7
Hem-fir #2 5-2 7-7 9-7 11-9 13-7 4-11 7-2 9-1 11-1 12-10
Hem-fir #3 4-0 5-10 7-4 9-0 10-5 3-9 5-6 6-11 8-6 9-10
Southern pine SS 6-4 10-0 13-2 16-9 20-4 6-4 10-0 13-2 16-5 19-2
Southern pine #1 6-3 9-3 11-8 13-10 16-6 5-11 8-9 11-0 13-1 15-7
Southern pine #2 5-7 8-1 10-5 12-5 14-7 5-4 7-7 9-10 11-9 13-9
Southern pine #3 4-3 6-3 8-0 9-5 11-2 4-0 5-11 7-6 8-10 10-7
Spruce-pine-fir SS 6-0 9-2 11-8 14-3 16-6 5-11 8-8 11-0 13-5 15-7
Spruce-pine-fir #1 5-3 7-8 9-9 11-11 13-10 5-0 7-3 9-2 11-3 13-0
Spruce-pine-fir #2 5-3 7-8 9-9 11-11 13-10 5-0 7-3 9-2 11-3 13-0
Spruce-pine-fir #3 4-0 5-10 7-4 9-0 10-5 3-9 5-6 6-11 8-6 9-10
24 Douglas fir-larch SS 6-0 8-10 11-3 13-9 15-11 5-9 8-4 10-7 12-11 15-0
Douglas fir-larch #1 5-0 7-4 9-4 11-5 13-2 4-9 6-11 8-9 10-9 12-5
Douglas fir-larch #2 4-8 6-11 8-9 10-8 12-4 4-5 6-6 8-3 10-0 11-8
Douglas fir-larch #3 3-7 5-2 6-7 8-1 9-4 3-4 4-11 6-3 7-7 8-10
Hem-fir SS 5-8 8-8 11-0 13-6 13-11 5-7 8-3 10-5 12-4 12-4
Hem-fir #1 4-11 7-2 9-1 11-1 12-10 4-7 6-9 8-7 10-6 12-2
Hem-fir #2 4-8 6-9 8-7 10-6 12-2 4-4 6-5 8-1 9-11 11-6
Hem-fir #3 3-7 5-2 6-7 8-1 9-4 3-4 4-11 6-3 7-7 8-10
Southern pine SS 5-11 9-3 12-2 15-7 18-2 5-11 9-3 12-2 14-8 17-2
Southern pine #1 5-7 8-3 10-5 12-5 14-9 5-3 7-10 9-10 11-8 13-11
Southern pine #2 5-0 7-3 9-4 11-1 13-0 4-9 6-10 8-9 10-6 12-4
Southern pine #3 3-9 5-7 7-1 8-5 10-0 3-7 5-3 6-9 7-11 9-5
Spruce-pine-fir SS 5-6 8-3 10-5 12-9 14-9 5-4 7-9 9-10 12-0 12-11
Spruce-pine-fir #1 4-8 6-11 8-9 10-8 12-4 4-5 6-6 8-3 10-0 11-8
Spruce-pine-fir #2 4-8 6-11 8-9 10-8 12-4 4-5 6-6 8-3 10-0 11-8
Spruce-pine-fir #3 3-7 5-2 6-7 8-1 9-4 3-4 4-11 6-3 7-7 8-10

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location.

When ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the factors given below:

HC/HR Rafter Span Adjustment Factor
1/3 0.67
1/4 0.76
1/5 0.83
1/6 0.90
1/ 7.5 or less 1.00

where:

HC= Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

HR= Height of roof ridge measured vertically above the top of the rafter support walls.

TABLE 802.5.1(8)

RAFTER SPANS FOR 70 PSF GROUND SNOW LOAD

(Ceiling attached to rafters, L/[DELTA] = 240)

RAFTER SPACING (inches) SPECIES AND GRADE DEAD LOAD = 10 psf DEAD LOAD = 20 psf
2 x 4 2 x 6 2 x 8 2 x 10 2 x 12 2 x 4 2 x 6 2 x 8 2 x 10 2 x 12
Maximum rafter spansa
(feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches) (feet -inches)
12 Douglas fir-larch SS 6-10 10-9 14-3 18-2 22-1 6-10 10-9 14-3 18-2 21-2
Douglas fir-larch #1 6-7 10-5 13-2 16-1 18-8 6-7 9-10 12-5 15-2 17-7
Douglas fir-larch #2 6-6 9-9 12-4 15-1 17-6 6-3 9-2 11-8 14-2 16-6
Douglas fir-larch #3 5-0 7-4 9-4 11-5 13-2 4-9 6-11 8-9 10-9 12-5
Hem-fir SS 6-6 10-2 13-5 17-2 20-10 6-6 10-2 13-5 17-2 20-10
Hem-fir #1 6-4 10-0 12-10 15-8 18-2 6-4 9-7 12-1 14-10 17-2
Hem-fir #2 6-1 9-6 12-2 14-10 17-3 6-1 9-1 11-5 14-0 16-3
Hem-fir #3 5-0 7-4 9-4 11-5 13-2 4-9 6-11 8-9 10-9 12-5
Southern pine SS 6-9 10-7 14-0 17-10 21-8 6-9 10-7 14-0 17-10 21-8
Southern pine #1 6-7 10-5 13-8 17-6 20-11 6-7 10-5 13-8 16-6 19-8
Southern pine #2 6-6 10-2 13-2 15-9 18-5 6-6 9-7 12-5 14-10 17-5
Southern pine #3 5-4 7-11 10-1 11-11 14-2 5-1 7-5 9-6 11-3 13-4
Spruce-pine-fir SS 6-4 10-0 13-2 16-9 20-5 6-4 10-0 13-2 16-9 19-8
Spruce-pine-fir #1 6-2 9-9 12-4 15-1 17-6 6-2 9-2 11-8 14-2 16-6
Spruce-pine-fir #2 6-2 9-9 12-4 15-1 17-6 6-2 9-2 11-8 14-2 16-6
Spruce-pine-fir #3 5-0 7-4 9-4 11-5 13-2 4-9 6-11 8-9 10-9 12-5
16 Douglas fir-larch SS 6-3 9-10 12-11 16-6 19-6 6-3 9-10 12-11 15-10 18-4
Douglas fir-larch #1 6-0 9-0 11-5 13-11 16-2 5-10 8-6 10-9 13-2 15-3
Douglas fir-larch #2 5-9 8-5 10-8 13-1 15-2 5-5 7-11 10-1 12-4 14-3
Douglas fir-larch #3 4-4 6-4 8-1 9-10 11-5 4-1 6-0 7-7 9-4 10-9
Hem-fir SS 5-11 9-3 12-2 15-7 18-11 5-11 9-3 12-2 15-7 18-0
Hem-fir #1 5-9 8-9 11-2 13-7 15-9 5-8 8-3 10-6 12-10 14-10
Hem-fir #2 5-6 8-4 10-6 12-10 14-11 5-4 7-10 9-11 12-1 14-1
Hem-fir #3 4-4 6-4 8-1 9-10 11-5 4-1 6-0 7-7 9-4 10-9
Southern pine SS 6-1 9-7 12-8 16-2 19-8 6-1 9-7 12-8 16-2 19-8
Southern pine #1 6-0 9-5 12-5 15-2 18-1 6-0 9-5 12-0 14-4 17-1
Southern pine #2 5-11 8-10 11-5 13-7 16-0 5-10 8-4 10-9 12-10 15-1
Southern pine #3 4-8 6-10 8-9 10-4 12-3 4-4 6-5 8-3 9-9 11-7
Spruce-pine-fir SS 5-9 9-1 11-11 15-3 18-1 5-9 9-1 11-11 14-8 17-1
Spruce-pine-fir #1 5-8 8-5 10-8 13-1 15-2 5-5 7-11 10-1 12-4 14-3
Spruce-pine-fir #2 5-8 8-5 10-8 13-1 15-2 5-5 7-11 10-1 12-4 14-3
Spruce-pine-fir #3 4-4 6-4 8-1 9-10 11-5 4-1 6-0 7-7 9-4 10-9
19.2 Douglas fir-larch SS 5-10 9-3 12-2 15-4 17-9 5-10 9-3 11-10 14-5 16-9
Douglas fir-larch #1 5-7 8-3 10-5 12-9 14-9 5-4 7-9 9-10 12-0 13-11
Douglas fir-larch #2 5-3 7-8 9-9 11-11 13-10 5-0 7-3 9-2 11-3 13-0
Douglas fir-larch #3 4-0 5-10 7-4 9-0 10-5 3-9 5-6 6-11 8-6 9-10
Hem-fir SS 5-6 8-8 11-6 14-8 17-4 5-6 8-8 11-6 14-2 15-5
Hem-fir #1 5-5 8-0 10-2 12-5 14-5 5-2 7-7 9-7 11-8 13-7
Hem-fir #2 5-2 7-7 9-7 11-9 13-7 4-11 7-2 9-1 11-1 12-10
Hem-fir #3 4-0 5-10 7-4 9-0 10-5 3-9 5-6 6-11 8-6 9-10
Southern pine SS 5-9 9-1 11-11 15-3 18-6 5-9 9-1 11-11 15-3 18-6
Southern pine #1 5-8 8-11 11-8 13-10 16-6 5-8 8-9 11-0 13-1 15-7
Southern pine #2 5-6 8-1 10-5 12-5 14-7 5-4 7-7 9-10 11-9 13-9
Southern pine #3 4-3 6-3 8-0 9-5 11-2 4-0 5-11 7-6 8-10 10-7
Spruce-pine-fir SS 5-5 8-6 11-3 14-3 16-6 5-5 8-6 11-0 13-5 15-7
Spruce-pine-fir #1 5-3 7-8 9-9 11-11 13-10 5-0 7-3 9-2 11-3 13-0
Spruce-pine-fir #2 5-3 7-8 9-9 11-11 13-10 5-0 7-3 9-2 11-3 13-0
Spruce-pine-fir #3 4-0 5-10 7-4 9-0 10-5 3-9 5-6 6-11 8-6 9-10
24 Douglas fir-larch SS 5-5 8-7 11-3 13-9 15-11 5-5 8-4 10-7 12-11 15-0
Douglas fir-larch #1 5-0 7-4 9-4 11-5 13-2 4-9 6-11 8-9 10-9 12-5
Douglas fir-larch #2 4-8 6-11 8-9 10-8 12-4 4-5 6-6 8-3 10-0 11-8
Douglas fir-larch #3 3-7 5-2 6-7 8-1 9-4 3-4 4-11 6-3 7-7 8-10
Hem-fir SS 5-2 8-1 10-8 13-6 13-11 5-2 8-1 10-5 12-4 12-4
Hem-fir #1 4-11 7-2 9-1 11-1 12-10 4-7 6-9 8-7 10-6 12-2
Hem-fir #2 4-8 6-9 8-7 10-6 12-2 4-4 6-5 8-1 9-11 11-6
Hem-fir #3 3-7 5-2 6-7 8-1 9-4 3-4 4-11 6-3 7-7 8-10
Southern pine SS 5-4 8-5 11-1 14-2 17-2 5-4 8-5 11-1 14-2 17-2
Southern pine #1 5-3 8-3 10-5 12-5 14-9 5-3 7-10 9-10 11-8 13-11
Southern pine #2 5-0 7-3 9-4 11-1 13-0 4-9 6-10 8-9 10-6 12-4
Southern pine #3 3-9 5-7 7-1 8-5 10-0 3-7 5-3 6-9 7-11 9-5
Spruce-pine-fir SS 5-0 7-11 10-5 12-9 14-9 5-0 7-9 9-10 12-0 12-11
Spruce-pine-fir #1 4-8 6-11 8-9 10-8 12-4 4-5 6-6 8-3 10-0 11-8
Spruce-pine-fir #2 4-8 6-11 8-9 10-8 12-4 4-5 6-6 8-3 10-0 11-8
Spruce-pine-fir #3 3-7 5-2 6-7 8-1 9-4 3-4 4-11 6-3 7-7 8-10

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. When ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the factors given below:

HC/HR Rafter Span Adjustment Factor
1/3 0.67
1/4 0.76
1/5 0.83
1/6 0.90
1/ 7.5 or less 1.00

where:

HC= Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

HR= Height of roof ridge measured vertically above the top of the rafter support walls.

TABLE 802.5.1(9)

RAFTER/CEILING JOIST HEEL JOINT CONNECTIONSa, b, c, d, e, f, h

RAFTER SLOPE RAFTERSPACING(inches) GROUND SNOW LOAD (psf)
20g 30 50 70
Roof span (feet)
12 20 28 36 12 20 28 12 36 20 28 36 12 20 28 36
Required number of 16d common nailsa, b per heel joint splicesc, d, e, f
3:12 12 4 6 8 10 4 6 8 11 5 8 12 15 6 11 15 20
16 5 8 10 13 5 8 11 14 6 11 15 20 8 14 20 26
24 7 11 15 19 7 11 16 21 9 16 23 30 12 21 30 39
4:12 12 3 5 6 8 3 5 6 8 4 6 9 11 5 8 12 15
16 4 6 8 10 4 6 8 11 5 8 12 15 6 11 15 20
24 5 8 12 15 5 9 12 16 7 12 17 22 9 16 23 29
5:12 12 3 4 5 6 3 4 5 7 3 5 7 9 4 7 9 12
16 3 5 6 8 3 5 7 9 4 7 9 12 5 9 12 16
24 4 7 9 12 4 7 10 13 6 10 14 18 7 13 18 23
7:12 12 3 4 4 5 3 3 4 5 3 4 5 7 3 5 7 9
16 3 4 5 6 3 4 5 6 3 5 7 9 4 6 9 11
24 3 5 7 9 3 5 7 9 4 7 10 13 5 9 13 17
9:12 12 3 3 4 4 3 3 3 4 3 3 4 5 3 4 5 7
16 3 4 4 5 3 3 4 5 3 4 5 7 3 5 7 9
24 3 4 6 7 3 4 6 7 3 6 8 10 4 7 10 13
12:12 12 3 3 3 3 3 3 3 3 3 3 3 4 3 3 4 5
16 3 3 4 4 3 3 3 4 3 3 4 5 3 4 5 7
24 3 4 4 5 3 3 4 6 3 4 6 8 3 6 8 10

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. 40d box nails shall be permitted to be substituted for 16d common nails.

b. Nailing requirements shall be permitted to be reduced 25 percent if nails are clinched.

c. Heel joint connections are not required when the ridge is supported by a load-bearing wall, header or ridge beam.

d. When intermediate support of the rafter is provided by vertical struts or purlins to a loadbearing wall, the tabulated heel joint connection requirements shall be permitted to be reduced proportionally to the reduction in span.

e. Equivalent nailing patterns are required for ceiling joist to ceiling joist lap splices.

f. When rafter ties are substituted for ceiling joists, the heel joint connection requirement shall be taken as the tabulated heel joint connection requirement for two-thirds of the actual rafter-slope.

g. Applies to roof live load of 20 psf or less.

h. Tabulated heel joint connection requirements assume that ceiling joists or rafter ties are located at the bottom of the attic space. When ceiling joists or rafter ties are located higher in the attic, heel joint connection requirements shall be increased by the following factors:

HC/HR Heel Joint Connection Adjustment Factor
1/3 1.5
1/4 1.33
1/5 1.25
1/6 1.2
1/10 or less 1.11

where:

HC= Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

HR= Height of roof ridge measured vertically above the top of the rafter support walls.


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20120529_1331-1.jpg

TABLE 802.11

REQUIRED STRENGTH OF TRUSS OR RAFTER CONNECTIONS TO RESIST WIND UPLIFT FORCESa,b,c,e,f

(Pounds per connection)

BASIC WIND SPEED (mph) (3-second gust) ROOF SPAN (feet) OVERHANGSd (pounds/foot)
12 20 24 28 32 36 40
85 -72 -120 -145 -169 -193 -217 -241 - 38.55
90 -91 -151 -181 -212 -242 -272 -302 - 43.22
100 -131 -218 -262 -305 -349 -393 -436 - 53.36
110 -175 -292 -351 -409 -467 -526 -584 - 64.56

For SI: 1 inch = 25.4 mm, 1 foot = 305 mm, 1 mph = 0.447 m/s, 1 pound/foot = 14.5939 N/m, 1 pound = 0.454 kg.

a. The uplift connection requirements are based on a 30 foot mean roof height located in Exposure B. For Exposures C and D and for other mean roof heights, multiply the above loads by the Adjustment Coefficients in Table 301.2(3).

b. The uplift connection requirements are based on the framing being spaced 24 inches on center. Multiply by 0.67 for framing spaced 16 inches on center and multiply by 0.5 for framing spaced 12 inches on center.

c. The uplift connection requirements include an allowance for 10 pounds of dead load.

d. The uplift connection requirements do not account for the effects of overhangs. The magnitude of the above loads shall be increased by adding the overhang loads found in the table. The overhang loads are also based on framing spaced 24 inches on center. The overhang loads given shall be multiplied by the overhang projection and added to the roof uplift value in the table.

e. The uplift connection requirements are based on wind loading on end zones as defined in Figure 6-2 of ASCE 7. Connection loads for connections located a distance of 20% of the least horizontal dimension of the building from the corner of the building are permitted to be reduced by multiplying the table connection value by 0.7 and multiplying the overhang load by 0.8.

f. For wall-to-wall and wall-to-foundation connections, the capacity of the uplift connector is permitted to be reduced by 100 pounds for each full wall above. (For example, if a 600-pound rated connector is used on the roof framing, a 500-pound rated connector is permitted at the next floor level down).

SECTION 803

ROOF SHEATHING

803.1 Lumber sheathing. Allowable spans for lumber used as roof sheathing shall conform to Table 803.1. Spaced lumber sheathing for wood shingle and shake roofing shall conform to the requirements of Sections 905.7 and 905.8. Spaced lumber sheathing is not allowed in Seismic Design Category D2.

TABLE 803.1

MINIMUM THICKNESS OF LUMBER ROOF SHEATHING

RAFTER OR BEAM SPACING (inches) MINIMUM NET THICKNESS (inches)
24 5/8
48a 11/2 T & G
60b
72c

For SI: 1 inch = 25.4 mm.

a. Minimum 270 Fb, 340,000 E.

b. Minimum 420 Fb, 660,000 E.

c. Minimum 600 Fb, 1,150,000 E.

803.2 Wood structural panel sheathing.

803.2.1 Identification and grade. Wood structural panels shall conform to DOC PS 1, DOC PS 2 or, when manufactured in Canada, CSA O437 or CSA O325, and shall be identified by a grade mark or certificate of inspection issued by an approved agency. Wood structural panels shall comply with the grades specified in Table 503.2.1.1(1).

803.2.1.1 Exposure durability. All wood structural panels, when designed to be permanently exposed in outdoor applications, shall be of an exterior exposure durability. Wood structural panel roof sheathing exposed to the underside may be of interior type bonded with exterior glue, identified as Exposure 1.

803.2.1.2 Fire-retardant-treated plywood. The allowable unit stresses for fire-retardant-treated plywood, including fastener values, shall be developed from an approved method of investigation that considers the effects of anticipated temperature and humidity to which the fire-retardant-treated plywood will be subjected, the type of treatment and redrying process. The fire-retardant-treated plywood shall be graded by an approved agency.

803.2.2 Allowable spans. The maximum allowable spans for wood structural panel roof sheathing shall not exceed the values set forth in Table 503.2.1.1(1), or APA E30.

803.2.3 Installation. Wood structural panel used as roof sheathing shall be installed with joints staggered or not staggered in accordance with Table 602.3(1), or APA E30 for wood roof framing or with Table 804.3 for steel roof framing.

SECTION 804

STEEL ROOF FRAMING

804.1 General. Elements shall be straight and free of any defects that would significantly affect their structural performance. Cold-formed steel roof framing members shall comply with the requirements of this section.

804.1.1 Applicability limits. The provisions of this section shall control the construction of cold-formed steel roof framing for buildings not greater than 60 feet (18 288 mm) perpendicular to the joist, rafter or truss span, not greater than 40 feet (12 192 mm) in width parallel to the joist span or truss, less than or equal to three stories above grade plane and with roof slopes not less than 3:12 (25-percent slope) or greater than 12:12 (100 percent slope). Cold-formed steel roof framing constructed in accordance with the provisions of this section shall be limited to sites subjected to a maximum design wind speed of 110 miles per hour (49 m/s), Exposure B or C, and a maximum ground snow load of 70 pounds per square foot (3350 Pa).

804.1.2 In-line framing. Cold-formed steel roof framing constructed in accordance with Section 804 shall be located in line with load-bearing studs in accordance with Figure 804.1.2 and the tolerances specified as follows:

1. The maximum tolerance shall be 3/4 inch ( 19.1 mm) between the centerline of the horizontal framing member and the centerline of the vertical framing member.

2. Where the centerline of the horizontal framing member and bearing stiffener are located to one side of the center line of the vertical framing member, the maximum tolerance shall be 1/8 inch (3 mm) between the web of the horizontal framing member and the edge of the vertical framing member.

804.2 Structural framing. Load-bearing cold-formed steel roof framing members shall comply with Figure 804.2(1) and with the dimensional and minimum thickness requirements specified in Tables 804.2(1) and 804.2(2). Tracks shall comply with Figure 804.2(2) and shall have a minimum flange width of 11/4 inches (32 mm). The maximum inside bend radius for members shall be the greater of 3/32 inch ( 2.4 mm) minus half the base steel thickness or 1.5 times the base steel thickness.

804.2.1 Material. Load-bearing cold-formed steel framing members shall be cold-formed to shape from structural quality sheet steel complying with the requirements of one of the following:

1. ASTM A 653: Grades 33 and 50 (Class 1 and 3).

2. ASTM A 792: Grades 33 and 50A.

3. ASTM A 1003: Structural Grades 33 Type H and 50 Type H.

804.2.2 Identification. Load-bearing cold-formed steel framing members shall have a legible label, stencil, stamp or embossment with the following information as a minimum:

1. Manufacturer's identification.

2. Minimum base steel thickness in inches (mm).

3. Minimum coating designation.

4. Minimum yield strength, in kips per square inch (ksi) (MPa).


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TABLE 804.2(1)

LOAD-BEARING COLD-FORMED STEEL MEMBER SIZES

NOMINAL MEMBER SIZE MEMBER DESIGNATIONa WEB DEPTH (inches) MINIMUM FLANGE WIDTH (inches) MAXIMUM FLANGE WIDTH (inches) MINIMUM LIP SIZE (inches)
350S162-t 3.5 1.625 2 0.5
550S162-t 5.5 1.625 2 0.5
800S162-t 8 1.625 2 0.5
1000S162-t 10 1.625 2 0.5
1200S162-t 12 1.625 2 0.5

For SI: 1 inch = 25.4 mm.

a. The member designation is defined by the first number representing the member depth in hundredths of an inch, the letter "s" representing a stud or joist member, the second number representing the flange width in hundredths of an inch, and the letter "t" shall be a number representing the minimum base metal thickness in mils [see Table 804.2(2) ].

TABLE 804.2(2)

MINIMUM THICKNESS OF COLD-FORMED STEEL MEMBERS

DESIGNATION THICKNESS (mils) MINIMUM BASE STEEL THICKNESS (inches)
33 0.0329
43 0.0428
54 0.0538
68 0.0677
97 0.0966

For SI: 1 inch = 25.4 mm, 1 mil = 0.0254 mm.


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804.2.3 Corrosion protection. Load-bearing cold-formed steel framing shall have a metallic coating complying with ASTM A 1003 and one of the following:

1. A minimum of G 60 in accordance with ASTM A 653.

2. A minimum of AZ 50 in accordance with ASTM A 792.

804.2.4 Fastening requirements. Screws for steel-to-steel connections shall be installed with a minimum edge distance and center-to-center spacing of 1/2 inch (13 mm), shall be self-drilling tapping, and shall conform to ASTM C 1513. Structural sheathing shall be attached to cold-formed steel roof rafters with minimum No. 8 self-drilling tapping screws that conform to ASTM C 1513. Screws for attaching structural sheathing to cold-formed steel roof framing shall have a minimum head diameter of 0.292 inch ( 7.4 mm) with countersunk heads and shall be installed with a minimum edge distance of 3/8 inch (10 mm). Gypsum board ceilings shall be attached to cold-formed steel joists with minimum No. 6 screws conforming to ASTM C 954 or ASTM C 1513 with a bugle head style and shall be installed in accordance with Section 805. For all connections, screws shall extend through the steel a minimum of three exposed threads. All fasteners shall have rust inhibitive coating suitable for the installation in which they are being used, or be manufactured from material not susceptible to corrosion.

Where No. 8 screws are specified in a steel-to-steel connection, reduction of the required number of screws in the connection is permitted in accordance with the reduction factors in Table 804.2.4 when larger screws are used or when one of the sheets of steel being connected is thicker than 33 mils ( 0.84 mm). When applying the reduction factor, the resulting number of screws shall be rounded up.

TABLE 804.2.4

SCREW SUBSTITUTION FACTOR

SCREW SIZE THINNEST CONNECTED STEEL SHEET (mils)
33 43
#8 1.0 0.67
#10 0.93 0.62
# 0.86 0.56

For SI: 1 mil = 0.0254 mm.

804.2.5 Web holes, web hole reinforcing and web hole patching. Web holes, web hole reinforcing, and web hole patching shall be in accordance with this section.

804.2.5.1 Web holes. Web holes in roof framing members shall comply with all of the following conditions:

1. Holes shall conform to Figure 804.2.5.1;

2. Holes shall be permitted only along the centerline of the web of the framing member;

3. Center-to-center spacing of holes shall not be less than 24 inches (610 mm);

4. The web hole width shall not be greater than one-half the member depth, or 21/2 inches ( 64.5 mm);

5. Holes shall have a web hole length not exceeding 41/2 inches (114 mm); and


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6. The minimum distance between the edge of the bearing surface and the edge of the web hole shall not be less than 10 inches (254 mm).

Framing members with web holes not conforming to the above requirements shall be reinforced in accordance with Section 804.2.5.2, patched in accordance with Section 804.2.5.3 or designed in accordance with accepted engineering practices.

For SI: 1 inch = 25.4 mm.

FIGURE 804.2.5.1

WEB HOLES

804.2.5.2 Web hole reinforcing. Reinforcement of web holes in ceiling joists not conforming to the requirements of Section 804.2.5.1 shall be permitted if the hole is located fully within the center 40 percent of the span and the depth and length of the hole does not exceed 65 percent of the flat width of the web. The reinforcing shall be a steel plate or C-shape section with a hole that does not exceed the web hole size limitations of Section 804.2.5.1 for the member being reinforced. The steel reinforcing shall be the same thickness as the receiving member and shall extend at least 1 inch ( 25.4 mm) beyond all edges of the hole. The steel reinforcing shall be fastened to the web of the receiving member with No.8 screws spaced no greater than 1 inch ( 25.4 mm) center-to-center along the edges of the patch with minimum edge distance of 1/2 inch (13 mm).

804.2.5.3 Hole patching. Patching of web holes in roof framing members not conforming to the requirements in Section 804.2.5.1 shall be permitted in accordance with either of the following methods:

1. Framing members shall be replaced or designed in accordance with accepted engineering practices where web holes exceed the following size limits:

1.

1. The depth of the hole, measured across the web, exceeds 70 percent of the flat width of the web; or

1.

2. The length of the hole measured along the web, exceeds 10 inches (254 mm) or the depth of the web, whichever is greater.

2. Web holes not exceeding the dimensional requirements in Section 804.2.5.3, Item 1, shall be patched with a solid steel plate, stud section or track section in accordance with Figure 804.2.5.3. The steel patch shall, as a minimum, be the same thickness as the receiving member and shall extend at least 1 inch (25 mm) beyond all edges of the hole. The steel patch shall be fastened to the web of the receiving member with No.8 screws spaced no greater than 1 inch (25 mm) center-to-center along the edges of the patch with minimum edge distance of 1/2 inch (13 mm).


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804.3 Roof construction. Cold-formed steel roof systems constructed in accordance with the provisions of this section shall consist of both ceiling joists and rafters in accordance with Figure 804.3 and fastened in accordance with Table 804.3, and hip framing in accordance with Section 804.3.3.

804.3.1 Ceiling joists. Cold-formed steel ceiling joists shall be in accordance with this section.

804.3.1.1 Minimum ceiling joist size. Ceiling joist size and thickness shall be determined in accordance with the limits set forth in Tables 804.3.1.1(1) through 804.3.1.1(8). When determining the size of ceiling joists, the lateral support of the top flange shall be classified as unbraced, braced at mid-span or braced at third points in accordance with Section 804.3.1.4. Where sheathing material is attached to the top flange of ceiling joists or where the bracing is spaced closer than third point of the joists, the "third point" values from Tables 804.3.1.1(1) through 804.3.1.1(8) shall be used.

Ceiling joists shall have a bearing support length of not less than 11/2 inches (38 mm) and shall be connected to roof rafters (heel joint) with No. 10 screws in accordance with Figures 804.3.1.1(1) and 804.3.1.1(2) and Table 804.3.1.1(9).

When continuous joists are framed across interior bearing supports, the interior bearing supports shall be located within 24 inches (610 mm) of midspan of the ceiling joist, and the individual spans shall not exceed the applicable spans in Tables 804.3.1.1(2), 804.3.1.1(4), 804.3.1.1(6) and 804.3.1.1(8).

When the attic is to be used as an occupied space, the ceiling joists shall be designed in accordance with Section 505.


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TABLE 804.3

ROOF FRAMING FASTENING SCHEDULEa,b

DESCRIPTION OF BUILDING ELEMENTS NUMBER AND SIZE OF FASTENERS SPACING OF FASTENERS
Ceiling joist to top track of load-bearing wall 2 No. 10 screws Each joist
Roof sheathing (oriented strand board or plywood) to rafters No. 8 screws 6" o.c. on edges and 12" o.c. at interior supports. 6" o.c. at gable end truss
Truss to bearing walla 2 No. 10 screws Each truss
Gable end truss to endwall top track No. 10 screws 12" o.c.
Rafter to ceiling joist Minimum No. 10 screws, per Table 804.3.1 Evenly spaced, not less than 1/2" from all edges.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mil = 0.0254 mm.

a. Screws shall be applied through the flanges of the truss or ceiling joist or a 54 mil clip angle shall be used with two No. 10 screws in each leg. See Section 804.3.9 for additional requirements to resist uplift forces.

b. Spacing of fasteners on roof sheathing panel edges applies to panel edges supported by framing members and at all roof plane perimeters. Blocking of roof sheathing panel edges perpendicular to the framing members shall not be required except at the intersection of adjacent roof planes. Roof perimeter shall be supported by framing members or cold-formed blocking of the same depth and gage as the floor members.

804.3.1.2 Ceiling joist bearing stiffeners. Where required in Tables 804.3.1.1(1) through 804.3.1.1(8), bearing stiffeners shall be installed at each bearing support in accordance with Figure 804.3.1.1(2). Bearing stiffeners shall be fabricated from a C-shaped or track member in accordance with the one of following:

1. C-shaped bearing stiffeners shall be a minimum 33 mils ( 0.84 mm) thick.

2. Track bearing stiffener shall be a minimum 43 mils ( 1.09 mm) thick.

The minimum length of a bearing stiffener shall be the depth of member being stiffened minus 3/8 inch ( 9.5 mm). Each stiffener shall be fastened to the web of the ceiling joist with a minimum of four No. 8 screws equally spaced as shown in Figure 804.3.1.1(2). Installation of stiffeners shall be permitted on either side of the web.

804.3.1.3 Ceiling joist bottom flange bracing. The bottom flanges of ceiling joists shall be laterally braced by the application of gypsum board or continuous steel straps installed perpendicular to the joist run in accordance with one of the following:

1. Gypsum board shall be fastened with No. 6 screws in accordance with Section 702.

2. Steel straps with a minimum size of 11/2 inches x 33 mils (38 mm x 0.84 mm) shall be installed at a maximum spacing of 4 feet (1219 mm). Straps shall be fastened to the bottom flange at each joist with one No.8 screw and shall be fastened to blocking with two No.8 screws. Blocking shall be installed between joists at a maximum spacing of 12 feet (3658 mm) measured along a line of continuous strapping (perpendicular to the joist run). Blocking shall also be located at the termination of all straps.

804.3.1.4 Ceiling joist top flange bracing. The top flanges of ceiling joists shall be laterally braced as required by Tables 804.3.1.1(1) through 804.3.1.1(8), in accordance with one of the following:

1. Minimum 33-mil ( 0.84 mm) C-shaped member in accordance with Figure 804.3.1.4(1).

2. Minimum 33-mil ( 0.84 mm) track section in accordance with Figure 804.3.1.4(1).

3. Minimum 33-mil ( 0.84 mm) hat section in accordance with Figure 804.3.1.4(1).

4. Minimum 54-mil ( 1.37 mm) 11/2 inch cold-rolled channel section in accordance with Figure 804.3.1.4(1).

5. Minimum 11/2 inch by 33 mil (38 mm by 0.84 mm) continuous steel strap in accordance with Figure 804.3.1.4(2).

Lateral bracing shall be installed perpendicular to the ceiling joists and shall be fastened to the top flange of each joist with one No. 8 screw. Blocking shall be installed between joists in line with bracing at a maximum spacing of 12 feet (3658 mm) measured perpendicular to the joists. Ends of lateral bracing shall be attached to blocking or anchored to a stable building component with two No. 8 screws.

804.3.1.5 Ceiling joist splicing. Splices in ceiling joists shall be permitted, if ceiling joist splices are supported at interior bearing points and are constructed in accordance with Figure 804.3.1.5. The number of screws on each side of the splice shall be the same as required for the heel joint connection in Table 804.3.1.1(9).

804.3.2 Roof rafters. Cold-formed steel roof rafters shall be in accordance with this section.

804.3.2.1 Minimum roof rafter sizes. Roof rafter size and thickness shall be determined in accordance with the limits set forth in Tables 804.3.2.1(1) and 804.3.2.1(2) based on the horizontal projection of the roof rafter span. For determination of roof rafter sizes, reduction of roof spans shall be permitted when a roof rafter support brace is installed in accordance with Section 804.3.2.2. The reduced roof rafter span shall be taken as the larger of the distance from the roof rafter support brace to the ridge or to the heel measured horizontally.

For the purpose of determining roof rafter sizes in Tables 804.3.2.1(1) and 804.3.2.1(2), wind speeds shall be converted to equivalent ground snow loads in accordance with Table 804.3.2.1(3). Roof rafter sizes shall be based on the higher of the ground snow load or the equivalent snow load converted from the wind speed.

804.3.2.1.1 Eave overhang. Eave overhangs shall not exceed 24 inches (610 mm) measured horizontally.

804.3.2.1.2 Rake overhangs. Rake overhangs shall not exceed 12 inches (305 mm) measured horizontally. Outlookers at gable endwalls shall be installed in accordance with Figure 804.3.2.1.2.

804.3.2.2 Roof rafter support brace. When used to reduce roof rafter spans in determining roof rafter sizes, a roof rafter support brace shall meet all of the following conditions:

1. Minimum 350S162-33 C-shaped brace member with maximum length of 8 feet (2438 mm).

2. Minimum brace member slope of 45 degrees ( 0.785 rad) to the horizontal.

3. Minimum connection of brace to a roof rafter and ceiling joist with four No.10 screws at each end.

4. Maximum 6 inches (152 mm) between brace/ceiling joist connection and load-bearing wall below.

5. Each roof rafter support brace greater than 4 feet (1219 mm) in length, shall be braced with a supplemental brace having a minimum size of 350S162-33 or 350T162-33 such that the maximum unsupported length of the roof rafter support brace is 4 feet (1219 mm). The supplemental brace shall be continuous and shall be connected to each roof rafter support brace using two No.8 screws.

804.3.2.3 Roof rafter splice. Roof rafters shall not be spliced.

804.3.2.4 Roof rafter to ceiling joist and ridge member connection.

Roof rafters shall be connected to a parallel ceiling joist to form a continuous tie between exterior walls in accordance with Figures 804.3.1.1(1) or 804.3.1.1(2) and Table 804.3.1.1(9). Ceiling joists shall be connected to the top track of the load-bearing wall in accordance with Table 804.3, either with two No.10 screws applied through the flange of the ceiling joist or by using a 54 mil ( 1.37 mm) clip angle with two No.10 screws in each leg. Roof rafters shall be connected to a ridge member with a minimum 2-inch by 2-inch (51 mm by 51 mm) clip angle fastened with No. 10 screws to the ridge member in accordance with Figure 804.3.2.4 and Table 804.3.2.4. The clip angle shall have a steel thickness equivalent to or greater than the roof rafter thickness and shall extend the depth of the roof rafter member to the extent possible. The ridge member shall be fabricated from a C-shaped member and a track section, which shall have a minimum size and steel thickness equivalent to or greater than that of adjacent roof rafters and shall be installed in accordance with Figure 804.3.2.4.The ridge member shall extend the full depth of the sloped roof rafter cut.

804.3.2.5 Roof rafter bottom flange bracing. The bottom flanges of roof rafters shall be continuously braced, at a maximum spacing of 8 feet (2440 mm) as measured parallel to the roof rafters, with one of the following members:

1. Minimum 33-mil ( 0.84 mm) C-shaped member.

2. Minimum 33-mil ( 0.84 mm) track section.

3. Minimum 11/2-inch by 33-mil (38 mm by 0.84 mm) steel strap.

The bracing element shall be fastened to the bottom flange of each roof rafter with one No.8 screw and shall be fastened to blocking with two No.8 screws. Blocking shall be installed between roof rafters in-line with the continuous bracing at a maximum spacing of 12 feet (3658 mm) measured perpendicular to the roof rafters. The ends of continuous bracing shall be fastened to blocking or anchored to a stable building component with two No.8 screws.

804.3.3 Hip framing. Hip framing shall consist of jack-rafters, hip members, hip support columns and connections in accordance with this section, or shall be in accordance with an approved design. The provisions of this section for hip members and hip support columns shall apply only where the jack rafter slope is greater than or equal to the roof slope. For the purposes of determining member sizes in this section, wind speeds shall be converted to equivalent ground snow load in accordance with Table 804.3.2.1(3).

804.3.3.1 Jack rafters. Jack rafters shall meet the requirements for roof rafters in accordance with Section 804.3.2, except that the requirements in Section 804.3.2.4 shall not apply.

804.3.3.2 Hip members. Hip members shall be fabricated from C-shape members and track section, which shall have minimum sizes determined in accordance with Table 804.3.3.2. The C-shape member and track section shall be connected at a maximum spacing of 24 inches (610 mm) using No. 10 screws through top and bottom flanges in accordance with Figure 804.3.2.4. The depth of the hip member shall match that of the roof rafters and jack rafters, or shall be based on an approved design for a beam pocket at the corner of the supporting wall.

804.3.3.3 Hip support columns. Hip support columns shall be used to support hip members at the ridge. A hip support column shall consist of a pair of C-shape members, with a minimum size determined in accordance with Table 804.3.3.3. The C-shape members shall be connected at a maximum spacing of 24 inches (610 mm) on center to form a box using minimum 3-inch (76 mm) x 33-mil ( 0.84 mm) strap connected to each of the flanges of the C-shape members with three-No. 10 screws. Hip support columns shall have a continuous load path to the foundation and shall be supported at the ceiling line by an interior wall or by an approved design for a supporting element.

TABLE 804.3.1.1(1)

CEILING JOIST SPANS SINGLE SPANS WITH BEARING STIFFENERS 10 lb per sq ft LIVE LOAD (NO ATTIC STORAGE)a,b,c 33 ksi STEEL

MEMBER DESIGNATION ALLOWABLE SPAN (feet-inches)
Lateral Support of Top (Compression) Flange
Unbraced Mid-Span Bracing Third-Point Bracing
Ceiling Joist Spacing (inches)
16 24 16 24 16 24
350S162-33 9'-5" 8'-6" 12'-2" 10'-4" 12'-2" 10'-7"
350S162-43 10'-3" 9'-2" 12'-10" 11'-2" 12'-10" 11'-2"
350S162-54 11'-1" 9'-11" 13'-9" 12'-0" 13'-9" 12'-0"
350S162-68 12'-1" 10-9" 14'-8" 12'-10" 14'-8" 12'-10"
350S162-97 14'-4" 12'-7" 16'-4" 14'-3" 16'-4" 14'-3"
550S162-33 10'-7" 9'-6" 14'-10" 12'-10" 15'-11" 13'-4"
550S162-43 11'-8" 10'-6" 16'-4" 14'-3" 17'-10" 15'-3"
550S162-54 12'-6" 11'-2" 17'-7" 15'-7" 19'-5" 16'-10"
550S162-68 13'-6" 12'-1" 19'-2" 17'-1" 21'-0" 18'-4"
550S162-97 15'-9" 13'-11" 21'-8" 19'-3" 23'-5" 20'-5"
800S162-33 12'-2" 10'-11" 17'-8" 15'-10" 19'-10" 17'-1"
800S162-43 13'-0" 11'-9" 18'-10" 17'-0" 21'-6" 19'-1"
800S162-54 13'-10" 12'-5" 20'-0" 18'-0" 22'-9" 20'-4"
800S162-68 14'-11" 13'-4" 21'-3" 19'-1" 24'-1" 21'-8"
800S162-97 17'-1" 15'-2" 23'-10" 21'-3" 26'-7" 23'-10"
1000S162-43 13'-11" 12'-6" 20'-2" 18'-3" 23'-1" 20'-9"
1000S162-54 14'-9" 13'-3" 21'-4" 19'-3" 24'-4" 22'-0"
1000S162-68 15'-10" 14'-2" 22'-8" 20'-5" 25'-9" 23'-2"
1000S162-97 18'-0" 16'-0" 25'-3" 22'-7" 28'-3" 25'-4"
1200S162-43 14'-8" 13'-3" 21'-4" 19'-3" 24'-5" 21'-8"
1200S162-54 15'-7" 14'-0" 22'-6" 20'-4" 25'-9" 23'-2"
1200S162-68 16'-8" 14'-11" 23'-11" 21'-6" 27'-2" 24'-6"
1000S162-97 18'-9" 16'-9" 26'-6" 23'-8" 29'-9" 26'-9"

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Deflection criterion: L/240 for total loads.

b. Ceiling dead load = 5 psf.

c. Bearing stiffeners are required at all bearing points and concentrated load locations.

TABLE 804.3.1.1(2)

CEILING JOIST SPANS TWO EQUAL SPANS WITH BEARING STIFFENERS 10 lb per sq ft LIVE LOAD (NO ATTIC STORAGE)a,b,c 33 ksi STEEL

MEMBER DESIGNATION ALLOWABLE SPAN (feet-inches)
Lateral Support of Top (Compression) Flange
Unbraced Mid-Span Bracing Third-Point Bracing
Ceiling Joist Spacing (inches)
   16 24 16 24 16 24
350S162-33 12'-11" 10'-11" 13'-5" 10'-11" 13'-5" 10'-11"
350S162-43 14'-2" 12'-8" 15'-10" 12'-11" 15'-10" 12'-11"
350S162-54 15'-6" 13'-10" 17'-1" 14'-6" 17'-9" 14'-6"
350S162-68 17'-3" 15'-3" 18'-6" 16'-1" 19'-8" 16'-1"
350S162-97 20'-10" 18'-4" 21'-5" 18'-10" 21'-11" 18'-10"
550S162-33 14'-4" 12'-11" 16'-7" 14'-1" 17'-3" 14'-1"
550S162-43 16'-0" 14'-1" 17'-11" 16'-1" 20'-7" 16'-10"
550S162-54 17'-4" 15'-6" 19'-5" 17'-6" 23'-2" 19'-0"
550S162-68 19'-1" 16'-11" 20'-10" 18'-8" 25'-2" 21'-5"
550S162-97 22'-8" 19'-9" 23'-6" 20'-11" 27'-11" 25'-1"
800S162-33 16'-5" 14'-10" 19'-2" 17'-3" 23'-1" 18'-3"
800S162-43 17'-9" 15'-11" 20'-6" 18'-5" 25'-0" 22'-6"
800S162-54 19'-1" 17'-1" 21'-8" 19'-6" 26'-4" 23'-9"
800S162-68 20'-9" 18'-6" 23'-1" 20'-9" 28'-0" 25'-2"
800S162-97 24'-5" 21'-6" 26'-0" 23'-2" 31'-1" 27'-9"
1000S162-43 18'-11" 17'-0" 21'-11" 19'-9" 26'-8" 24'-1"
1000S162-54 20'-3" 18'-2" 23'-2" 20'-10" 28'-2" 25'-5"
1000S162-68 21'-11" 19'-7" 24'-7" 22'-2" 29'-10" 26'-11"
1000S162-97 25'-7" 22'-7" 27'-6" 24'-6" 33'-0" 29'-7"
1200S162-43 19'-11" 17'-11" 23'-1" 20'-10" 28'-3" 25'-6"
1200S162-54 21'-3" 19'-1" 24'-5" 22'-0" 29'-9" 26'-10"
1200S162-68 23'-0" 20'-7" 25'-11" 23'-4" 31'-6" 28'-4"
1000S162-97 26'-7" 23'-6" 28'-9" 25'-10" 34'-8" 31'-1"

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Deflection criterion: L/240 for total loads.

b. Ceiling dead load = 5 psf.

c. Bearing stiffeners are required at all bearing points and concentrated load locations.

TABLE 804.3.1.1(3)

CEILING JOIST SPANS SINGLE SPANS WITH BEARING STIFFENERS 20 lb per sq ft LIVE LOAD (LIMITED ATTIC STORAGE)a,b,c 33 ksi STEEL

MEMBER DESIGNATION ALLOWABLE SPAN (feet-inches)
Lateral Support of Top (Compression) Flange
Unbraced Mid-Span Bracing Third-Point Bracing
Ceiling Joist Spacing (inches)
16 24 16 24 16 24
350S162-33 8'-2" 7'-2" 9'-9" 8'-1" 9'-11" 8'-1"
350S162-43 8'-10" 7'-10" 11'-0" 9'-5" 11'-0" 9'-7'
350S162-54 9'-6" 8'-6" 11'-9" 10'-3" 11'-9" 10'-3"
350S162-68 10'-4" 9'-2" 12'-7" 11'-0" 12'-7" 11'-0"
350S162-97 12'-1" 10'-8" 14'-0" 12'-0" 14'-0" 12'-0"
550S162-33 9'-2" 8'-3" 12'-2" 10'-2" 12'-6" 10'-5"
550S162-43 10'-1" 9'-1" 13'-7" 11'-7" 14'-5" 12'-2"
550S162-54 10'-9" 9'-8" 14'-10" 12'-10" 15'-11" 13'-6"
550S162-68 11'-7" 10'-4" 16'-4" 14'-0" 17'-5" 14'-11"
550S162-97 13'-4" 11'-10" 18'-5" 16'-2" 20'-1" 17'-1"
800S162-33 10'-7" 9'-6" 15'-1" 13'-0" 16'-2" 13'-7"
800S162-43 11'-4" 10'-2" 16'-5" 14'-6" 18'-2" 15'-9"
800S162-54 12'-0" 10'-9" 17'-4" 15'-6" 19'-6" 17'-0"
800S162-68 12'-10" 11'-6" 18'-5" 16'-6" 20'-10" 18'-3"
800S162-97 14'-7" 12'-11" 20'-5" 18'-3" 22'-11" 20'-5"
1000S162-43 12'-1" 10'-11" 17'-7" 15'-10" 19'-11" 17'-3"
1000S162-54 12'-10" 11'-6" 18'-7" 16'-9" 21'-2" 18'-10"
1000S162-68 13'-8" 12'-3" 19'-8" 17'-8" 22'-4" 20'-1"
1000S162-97 15'-4" 13'-8" 21'-8" 19'-5" 24'-5" 21'-11"
1200S162-43 12'-9" 11'-6" 18'-7" 16'-6" 20'-9" 18'-2"
1200S162-54 13'-6" 12'-2" 19'-7" 17'-8" 22'-5" 20'-2"
1200S162-68 14'-4" 12'-11" 20'-9" 18'-8" 23'-7" 21'-3"
1000S162-97 16'-1" 14'-4" 22'-10" 20'-6" 25'-9" 23'-2"

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Deflection criterion: L/240 for total loads.

b. Ceiling dead load = 5 psf.

c. Bearing stiffeners are required at all bearing points and concentrated load locations.

TABLE 804.3.1.1(4)

CEILING JOIST SPANS TWO EQUAL SPANS WITH BEARING STIFFENERS 20 lb per sq ft LIVE LOAD (LIMITED ATTIC STORAGE)a,b,c 33 ksi STEEL

MEMBER DESIGNATION ALLOWABLE SPAN (feet-inches)
Lateral Support of Top (Compression) Flange
Unbraced Mid-Span Bracing Third-Point Bracing
Ceiling Joist Spacing (inches)
16 24 16 24 16 24
350S162-33 10'-2" 8'-4" 10'-2" 8'-4" 10'-2" 8'-4"
350S162-43 12'-1" 9'-10" 12'-1' 9'-10" 12'-1" 9'-10"
350S162-54 13'-3" 11'-0" 13'-6" 11'-0" 13'-6" 11'-0"
350S162-68 14'-7" 12'-3" 15'-0" 12'-3" 15'-0" 12'-3"
350S162-97 17'-6" 14'-3" 17'-6" 14'-3" 17'-6" 14'-3"
550S162-33 12'-5" 10'-9" 13'-2" 10'-9" 13'-2" 10'-9"
550S162-43 13'-7" 12'-1" 15'-6" 12'-9" 15'-8" 12'-9"
550S162-54 14'-11" 13'-4" 16'-10" 14'-5" 17'-9" 14'-5"
550S162-68 16'-3" 14'-5" 18'-0" 16'-1" 20'-0" 16'-4"
550S162-97 19'-1" 16'-10" 20'-3" 18'-0" 23'-10" 19'-5"
800S162-33 14'-3" 12'-4" 16'-7" 12'-4" 16'-7" 12'-4"
800S162-43 15'-4" 13'-10" 17'-9" 16'-0" 21'-8" 17'-9"
800S162-54 16'-5" 14'-9" 18'-10" 16'-11" 22'-11" 20'-6"
800S162-68 17'-9" 15'-11" 20'-0" 18'-0" 24'-3" 21'-10"
800S162-97 20'-8" 18'-3" 22'-3" 19'-11" 26'-9" 24'-0"
1000S162-43 16'-5" 14'-9" 19'-0" 17'-2" 23'-3" 18'-11"
1000S162-54 17'-6" 15'-8" 20'-1" 18'-1" 24'-6" 22'-1"
1000S162-68 18'-10" 16'-10" 21'-4" 19'-2" 25'-11" 23'-4"
1000S162-97 21'-8" 19'-3" 23'-7" 21'-2" 28'-5" 25'-6"
1200S162-43 17'-3" 15'-7" 20'-1" 18'-2" 24'-6" 18'-3"
1200S162-54 18'-5" 16'-6" 21'-3" 19'-2" 25'-11" 23'-5"
1200S162-68 19'-9" 17'-8" 22'-6" 20'-3" 27'-4" 24'-8"
1000S162-97 22'-7" 20'-1" 24'-10" 22'-3" 29'-11" 26'-11"

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Deflection criterion: L/240 for total loads.

b. Ceiling dead load = 5 psf.

c. Bearing stiffeners are required at all bearing points and concentrated load locations.

TABLE 804.3.1.1(5)

CEILING JOIST SPANS SINGLE SPANS WITHOUT BEARING STIFFENERS 10 lb per sq ft LIVE LOAD (NO ATTIC STORAGE)a,b 33 ksi STEEL

MEMBER DESIGNATION ALLOWABLE SPAN (feet-inches)
Lateral Support of Top (Compression) Flange
Unbraced Mid-Span Bracing Third-Point Bracing
Ceiling Joist Spacing (inches)
16 24 16 24 16 24
350S162-33 9'-5" 8'-6" 12'-2" 10'-4" 12'-2" 10'-7"
350S162-43 10'-3" 9'-12" 13'-2" 11'-6" 13'-2" 11'-6"
350S162-54 11'-1" 9'-11" 13'-9" 12'-0" 13'-9" 12'-0"
350S162-68 12'-1" 10'-9" 14'-8" 12'-10" 14'-8" 12'-10"
350S162-97 14'-4" 12'-7" 16'-10" 14'-3" 16'-4" 14'-3"
550S162-33 10'-7" 9'-6" 14'-10" 12'-10" 15'-11" 13'-4"
550S162-43 11'-8" 10'-6" 16'-4" 14'-3" 17'-10" 15'-3"
550S162-54 12'-6" 11'-2" 17'-7" 15'-7" 19'-5" 16'-10"
550S162-68 13'-6" 12'-1" 19'-2" 17'-0" 21'-0" 18'-4"
550S162-97 15'-9" 13'-11" 21'-8" 19'-3" 23'-5" 20'-5"
800S162-33 - - - - - -
800S162-43 13'-0" 11'-9" 18'-10" 17'-0" 21'-6" 19'-0"
800S162-54 13'-10" 12'-5" 20'-0" 18'-0" 22'-9" 20'-4"
800S162-68 14'-11" 13'-4" 21'-3" 19'-1" 24'-1" 21'-8"
800S162-97 17'-1" 15'-2" 23'-10" 21'-3" 26'-7" 23'-10"
1000S162-43 - - - - - -
1000S162-54 14'-9" 13'-3" 21'-4" 19'-3" 24'-4" 22'-0"
1000S162-68 15'-10" 14'-2" 22'-8" 20'-5" 25'-9" 23'-2"
1000S162-97 18'-0" 16'-0" 25'-3" 22'-7" 28'-3" 25'-4"
1200S162-43 - - - - - -
1200S162-54 - - - - - -
1200S162-68 16'-8" 14'-11" 23'-11" 21'-6" 27'-2" 24'-6"
1000S162-97 18'-9" 16'-9" 26'-6" 23'-8" 29'-9" 26'-9"

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Deflection criterion: L/240 for total loads.

b. Ceiling dead load = 5 psf.

TABLE 804.3.1.1(6)

CEILING JOIST SPANS TWO EQUAL SPANS WITHOUT BEARING STIFFENERS 10 lb per sq ft LIVE LOAD (NO ATTIC STORAGE)a, b 33 ksi STEEL

MEMBER DESIGNATION ALLOWABLE SPAN (feet-inches)
Lateral Support of Top (Compression) Flange
Unbraced Mid-Span Bracing Third-Point Bracing
Ceiling Joist Spacing (inches)
16 24 16 24 16 24
350S162-33 11'-9" 8'-11" 11'-9" 8'-11" 11'-9" 8'-11"
350S162-43 14'-2" 11'-7" 14'-11" 11'-7" 14'-11" 11'-7"
350S162-54 15'-6" 13'-10" 17'-1" 13'-10" 17'-7" 13'-10"
350S162-68 17'-3" 15'-3" 18'-6" 16'-1" 19'-8" 16'-1"
350S162-97 20'-10" 18'-4" 21'-5" 18'-9" 21'-11" 18'-9"
550S162-33 13'-4" 9'-11" 13'-4" 9'-11" 13'-4" 9'-11"
550S162-43 16'-0" 13'-6" 17'-9" 13'-6" 17'-9" 13'-6"
550S162-54 17'-4" 15'-6" 19'-5" 16'-10" 21'-9" 16'-10"
550S162-68 19'-1" 16'-11" 20'-10" 18'-8" 24'-11" 20'-6"
550S162-97 22'-8" 20'-0" 23'-9" 21'-1" 28'-2" 25'-1"
800S162-33 - - - - - -
800S162-43 17'-9" 15'-7" 20'-6" 15'-7" 21'-0" 15'-7"
800S162-54 19'-1" 17'-1" 21'-8" 19'-6" 26'-4" 23'-10"
800S162-68 20'-9" 18'-6" 23'-1" 20'-9" 28'-0" 25'-2"
800S162-97 24'-5" 21'-6" 26'-0" 23'-2" 31'-1" 27'-9"
1000S162-43 - - - - - -
1000S162-54 20'-3" 18'-2" 23'-2" 20'-10" 28'-2" 21'-2"
1000S162-68 21'-11" 19'-7" 24'-7" 22'-2" 29'-10" 26'-11"
1000S162-97 25'-7" 22'-7" 27'-6" 24'-6" 33'-0" 29'-7"
1200S162-43 - - - - - -
1200S162-54 - - - - - -
1200S162-68 23'-0" 20'-7" 25'-11" 23'-4" 31'-6" 28'-4"
1000S162-97 26'-7" 23'-6" 28'-9" 25'-10" 34'-8" 31'-1"

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Deflection criterion: L/240 for total loads.

b. Ceiling dead load = 5 psf.

TABLE 804.3.1.1(7)

CEILING JOIST SPANS SINGLE SPANS WITHOUT BEARING STIFFENERS 20 lb per sq ft LIVE LOAD (LIMITED ATTIC STORAGE)a,b 33 ksi STEEL

MEMBER DESIGNATION ALLOWABLE SPAN (feet-inches)
Lateral Support of Top (Compression) Flange
Unbraced Mid-Span Bracing Third-Point Bracing
Ceiling Joist Spacing (inches)
16 24 16 24 16 24
350S162-33 8'-2" 6'-10" 9'-9" 6'-10" 9'-11" 6'-10"
350S162-43 8'-10" 7'-10" 11'-0" 9'-5" 11'-0" 9'-7"
350S162-54 9'-6" 8'-6" 11'-9" 10'-3" 11'-9" 10'-3"
350S162-68 10'-4" 9'-2" 12'-7" 11'-0" 12'-7" 11'-0"
350S162-97 12'-10" 10'-8" 13'-9" 12'-0" 13'-9" 12'-0"
550S162-33 9'-2" 8'-3" 12'-2" 8'-5" 12'-6" 8'-5"
550S162-43 10'-1" 9'-1" 13'-7" 11'-8" 14'-5" 12'-2"
550S162-54 10'-9" 9'-8" 14'-10" 12'-10" 15'-11" 13'-6"
550S162-68 11'-7" 10'-4" 16'-4" 14'-0" 17'-5" 14'-11"
550S162-97 13'-4" 11'-10" 18'-5" 16'-2" 20'-1" 17'-4"
800S162-33 - - - - - -
800S162-43 11'-4" 10'-1" 16'-5" 13'-6" 18'-1" 13'-6"
800S162-54 20'-0" 10'-9" 17'-4" 15'-6" 19'-6" 27'-0"
800S162-68 12'-10" 11'-6" 18'-5" 16'-6" 20'-10" 18'-3"
800S162-97 14'-7" 12'-11" 20'-5" 18'-3" 22'-11" 20'-5"
1000S162-43 - - - - - -
1000S162-54 12'-10" 11'-6" 18'-7" 16'-9" 21'-2" 15'-5"
1000S162-68 13'-8" 12'-3" 19'-8" 17'-8" 22'-4" 20'-1"
1000S162-97 15'-4" 13'-8" 21'-8" 19'-5" 24'-5" 21'-11"
1200S162-43 - - - - - -
1200S162-54 - - - - - -
1200S162-68 14'-4" 12'-11" 20'-9" 18'-8" 23'-7" 21'-3"
1000S162-97 16'-1" 14'-4" 22'-10" 20'-6" 25'-9" 23'-2"

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Deflection criterion: L/240 for total loads.

b. Ceiling dead load = 5 psf.

TABLE 804.3.1.1(8)

CEILING JOIST SPANS TWO EQUAL SPANS WITHOUT BEARING STIFFENERS 20 lb per sq ft LIVE LOAD (LIMITED ATTIC STORAGE)a,b 33 ksi STEEL

MEMBER DESIGNATION ALLOWABLE SPAN (feet-inches)
Lateral Support of Top (Compression) Flange
Unbraced Mid-Span Bracing Third-Point Bracing
Ceiling Joist Spacing (inches)
16 24 16 24 16 24
350S162-33 8'-1" 6'-1" 8'-1" 6'-1" 8'-1" 6'-1"
350S162-43 10'-7" 8'-1" 10'-7" 8'-1" 10'-7" 8'-1"
350S162-54 12'-8" 9'-10" 12'-8" 9'-10" 12'-8" 9'-10"
350S162-68 14'-7" 11'-10" 14'-11" 11'-10" 14'-11" 11'-10"
350S162-97 17'-6" 14'-3" 17'-6" 14'-3" 17'-6" 14'-3"
550S162-33 8'-11" 6'-8" 8'-11" 6'-8" 8'-11" 6'-8"
550S162-43 12'-3" 9'-2" 12'-3" 9'-2" 12'-3" 9'-2"
550S162-54 14'-11" 11'-8" 15'-4" 11'-8" 15'-4" 11'-8"
550S162-68 16'-3" 14'-5" 18'-0" 15'-8" 18'-10" 14'-7"
550S162-97 19'-1" 16'-10" 20'-3" 18'-0" 23'-9" 19'-5"
800S162-33 - - - - - -
800S162-43 13'-11" 9'-10" 13'-11" 9'-10" 13'-11" 9'-10"
800S162-54 16'-5" 13'-9" 18'-8" 13'-9" 18'-8" 13'-9"
800S162-68 17'-9" 15'-11" 20'-0" 18'-0" 24'1" 18'-3"
800S162-97 20'-8" 18'-3" 22'-3" 19'-11" 26'-9" 24'-0"
1000S162-43 - - - - - -
1000S162-54 17'-6" 13'-11" 19'-1" 13'-11" 19'-1" 13'-11"
1000S162-68 18'-10" 16'-10" 21'-4" 19'-2" 25'-11" 19'-7"
1000S162-97 21'-8" 19'-3" 23'-7" 21'-2" 28'-5" 25'-6"
1200S162-43 - - - - - -
1200S162-54 - - - - - -
1200S162-68 19'-9" 17'-8" 22'-6" 19'-8" 26'-8" 19'-8"
1000S162-97 22'-7" 20'-1" 24'-10" 22'-3" 29'-11" 26'-11"

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Deflection criterion: L/240 for total loads.

b. Ceiling dead load = 5 psf.


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20120529_1331-7.jpg

TABLE 804.3.1.1(9)

NUMBER OF SCREWS REQUIRED FOR CEILING JOIST TO ROOF RAFTER CONNECTIONa

ROOF SLOPE NUMBER OF SCREWS
Building width (feet)
24 28 32 36 40
20 30 50 70 20 30 50 70 20 30 50 70 20 30 50 70 20 30 50 70
3/12 5 6 9 11 5 7 10 13 6 8 11 15 7 8 13 17 8 9 14 19
4/12 4 5 7 9 4 5 8 10 5 6 9 12 5 7 10 13 6 7 11 14
5/12 3 4 6 7 4 4 6 8 4 5 7 10 5 5 8 11 5 6 9 12
6/12 3 3 5 6 3 4 6 7 4 4 6 8 4 5 7 9 4 5 8 10
7/12 3 3 4 6 3 3 5 7 3 4 6 7 4 4 6 8 4 5 7 9
8/12 2 3 4 5 3 3 5 6 3 4 5 7 3 4 6 8 4 4 6 8
9/12 2 3 4 5 3 3 4 6 3 3 5 6 3 4 5 7 3 4 6 8
10/12 2 2 4 5 2 3 4 5 3 3 5 6 3 3 5 7 3 4 6 7
11/12 2 2 3 4 2 3 4 5 3 3 4 6 3 3 5 6 3 4 5 7
12/12 2 2 3 4 2 3 4 5 2 3 4 5 3 3 5 6 3 4 5 7

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20120529_1331-8.jpg


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20120529_1331-9.jpg

TABLE 804.3.2.1(1)

ROOF RAFTER SPANSa,b,c 33 ksi STEEL

MEMBER DESIGNATION ALLOWABLE SPAN MEASURED HORIZONTALLY (feet-inches)
Ground snow load (psf)
20 30 50 70
Rafter spacing (inches)
16 24 16 24 16 24 16 24
550S162-33 14'-0" 11'-6" 11'-11" 9'-7" 9'-6" 7'-9" 8'-2" 6'-8"
550S162-43 16'-8" 13'-11" 14'-5" 11'-9" 11'-6" 9'-5" 9'-10" 8'-0"
550S162-54 17'-11" 15'-7" 15'-7" 13'-3" 12'-11" 10'-7" 11'-1" 9'-1"
550S162-68 19'-2" 16'-9" 16'-9" 14'-7" 14'-1" 11'-10" 12'-6" 10'-2"
550S162-97 21'-3" 18'-6" 18'-6" 16'-2" 15'-8" 13'-8" 14'-0" 12'-2"
800S162-33 16'-5" 13'-5" 13'-11" 11'-4" 11'-1" 8'-2" 9'-0" 6'-0"
800S162-43 19'-9" 16'-1" 16'-8" 13'-7" 13'-4" 10'-10" 11'-5" 9'-4"
800S162-54 22'-8" 18'-6" 19'-2" 15'-8" 15'-4" 12'-6" 13'-1" 10'-8"
800S162-68 25'-10" 21'-2" 21'-11" 17'-10" 17'-6" 14'-4" 15'-0" 12'-3"
800S162-97 21'-3" 18'-6" 18'-6" 16'-2" 15'-8" 13'-8" 14'-0" 12'-2"
1000S162-43 22'-3" 18'-2" 18'-9" 15'-8" 15'-0" 12'-3" 12'-10" 10'-6"
1000S162-54 25'-8" 20'-11" 21'-8" 17'-9" 17'-4" 14'-2" 14'-10" 12'-1"
1000S162-68 29'-7" 24'-2" 25'-0" 20'-5" 20'-0" 16'-4" 17'-2" 14'-0"
1000S162-97 34'-8" 30'-4" 30'-4" 25'-10" 25'-3" 20'-8" 21'-8" 17'-8"
1200S162-54 28'-3" 23'-1" 23'-11" 19'-7" 19'-2" 15'-7" 16'-5" 13'-5"
1200S162-68 32'-10" 26'-10" 27'-9" 22'-8" 22'-2" 18'-1" 19'-0" 15'-6"
1200S162-97 40'-6" 33'-5" 34'-6" 28'-3" 27'-7" 22'-7" 23'-8" 19'-4"

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Table provides maximum horizontal rafter spans in feet and inches for slopes between 3:12 and 12:12.

b. Deflection criterion: L/240 for live loads and L/180 for total loads.

c. Roof dead load = 12 psf.

TABLE 804.3.2.1(2)

ROOF RAFTER SPANSa,b,c 50 ksi STEEL

MEMBER DESIGNATION ALLOWABLE SPAN MEASURED HORIZONTALLY (feet-inches)
Equivalent ground snow load (psf)
20 30 50 70
Rafter spacing (inches)
16 24 16 24 16 24 16 24
550S162-33 15'-4" 12'-11" 13'-4" 10'-11" 10'-9" 8'-9" 9'-2" 7'-6"
550S162-43 16'-8" 14'-7" 14'-7" 12'-9" 12'-3" 10'-6" 11'-0" 9'-0"
550S162-54 17'-11" 15'-7" 15'-7" 13'-8" 13'-2" 11'-6" 11'-9" 10'-3"
550S162-68 19'-2" 16'-9" 16'-9" 14'-7" 14'-1" 12'-4" 12'-7" 11'-0"
550S162-97 21'-3" 18'-6" 18'-6" 16'-2" 15'-8" 13'-8" 14'-0" 12'-3"
800S162-33 18'-10" 15'-5" 15'-11" 12'-9" 12'-3" 8'-2" 9'-0" 6'-0"
800S162-43 22'-3" 18'-2" 18'-10" 15'-5" 15'-1" 12'-3" 12'-11" 10'-6"
800S162-54 24'-2" 21'-2" 21'-1" 18'-5" 17'-10" 14'-8" 15'-5" 12'-7"
800S162-68 25'-11" 22'-8" 22'-8" 19'-9" 19'-1" 16'-8" 17'-1" 14'-9"
800S162-97 28'-10" 25'-2" 25'-2" 22'-0" 21'-2" 18'-6" 19'-0" 16'-7"
1000S162-43 25'-2" 20'-7" 21'-4" 17'-5" 17'-0" 13'-11" 14'-7" 10'- 7"
1000S162-54 29'-0" 24'-6" 25'-4" 20'-9" 20'-3" 16'-7" 17'-5" 14'-2"
1000S162-68 31'-2" 27'-3" 27'-3" 23'-9" 20'-0" 19'-6" 20'-6" 16'-8"
1000S162-97 34'-8" 30'-4" 30'-4" 26'-5" 25'-7" 22'-4" 22'-10" 20'-0"
1200S162-54 33'-2" 27'-1" 28'-1" 22'-11" 22'-5" 18'-4" 19'-3" 15'-8"
1200S162-68 36'-4" 31'-9" 31'-9" 27'-0" 26'-5" 21'-6" 22'-6" 18'-6"
1200S162-97 40'-6" 35'-4" 35'-4" 30'-11" 29'-10" 26'-1" 26'-8" 23'-1"

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Table provides maximum horizontal rafter spans in feet and inches for slopes between 3:12 and 12:12.

b. Deflection criterion: L/240 for live loads and L/180 for total loads.

c. Roof dead load = 12 psf.

TABLE 804.3.2.1(3)

BASIC WIND SPEED TO EQUIVALENT SNOW LOAD CONVERSION

BASIC WIND SPEED AND EXPOSURE EQUIVALENT GROUND SNOW LOAD (psf)
Roof slope
Exp. B Exp. C 3:12 4:12 5:12 6:12 7:12 8:12 9:12 10:12 11:12 12:12
85 mph - 20 20 20 20 20 20 30 30 30 30
100 mph 85 mph 20 20 20 20 30 30 30 30 50 50
110 mph 100 mph 20 20 20 20 30 50 50 50 50 50
- 110 mph 30 30 30 50 50 50 70 70 70 -

For SI: 1 mile per hour = 0.447 m/s, 1 pound per square foot = 0.0479 kPa.


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20120529_1331-10.jpg

804.3.3.4 Hip framing connections. Hip rafter framing connections shall be installed in accordance with the following:

1. Jack rafters shall be connected at the eave to a parallel C-shape blocking member in accordance with Figure 804.3.3.4(1). The C-shape blocking member shall be attached to the supporting wall track with minimum two No. 10 screws.

2. Jack rafters shall be connected to a hip member with a minimum 2 inch x 2 inch (51mm x 51 mm) clip angle fastened with No. 10 screws to the hip member in accordance with Figure 804.3.2.1.2 and Table 804.3.2.4. The clip angle shall have a steel thickness equivalent to or greater than the jack rafter thickness and shall extend the depth of the jack rafter member to the extent possible.

3. The connection of the hip support columns at the ceiling line shall be in accordance with Figure 804.3.3.4(2), with an uplift strap sized in accordance with Table 804.3.3.4(1).

4. The connection of hip support members, ridge members and hip support columns at the ridge shall be in accordance with Figures 804.3.3.4(3) and 804.3.3.4(4) and Table 804.3.3.4(2).

5. The connection of hip members to the wall corner shall be in accordance with Figure 804.3.3.4(5) and Table 804.3.3.4(3).

804.3.4 Cutting and notching. Flanges and lips of load-bearing cold-formed steel roof framing members shall not be cut or notched.

804.3.5 Headers. Roof-ceiling framing above wall openings shall be supported on headers. The allowable spans for headers in load-bearing walls shall not exceed the values set forth in Section 603.6 and Tables 603.6(1) through 603.6(24).

804.3.6 Framing of openings in roofs and ceilings. Openings in roofs and ceilings shall be framed with header and trimmer joists. Header joist spans shall not exceed 4 feet (1219 mm) in length. Header and trimmer joists shall be fabricated from joist and track members having a minimum size and thickness at least equivalent to the adjacent ceiling joists or roof rafters and shall be installed in accordance with Figures 804.3.6(1) and 804.3.6(2). Each header joist shall be connected to trimmer joists with a minimum of four 2-inch by 2-inch (51 by 51 mm) clip angles. Each clip angle shall be fastened to both the header and trimmer joists with four No. 8 screws, evenly spaced, through each leg of the clip angle. The steel thickness of the clip angles shall be not less than that of the ceiling joist or roof rafter. Each track section for a built-up header or trimmer joist shall extend the full length of the joist (continuous).


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TABLE 804.3.2.4

SCREWS REQUIRED AT EACH LEG OF CLIP ANGLE FOR HIP RAFTER TO HIP MEMBER OR ROOF RAFTER TO RIDGE MEMBER CONNECTIONa

BUILDING WIDTH (feet) NUMBER OF SCREWS
Ground snow load (psf)
0 to 20 21 to 30 31 to 50 51 to 70
24 2 2 3 4
28 2 3 4 5
32 2 3 4 5
36 3 3 5 6
40 3 4 5 7

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Screw s shall be No. 10 minimum.

804.3.7 Roof trusses. Cold-formed steel trusses shall be designed and installed in accordance with AISI S100, Section D4. Trusses shall be connected to the top track of the load-bearing wall in accordance with Table 804.3, either with two No.10 screws applied through the flange of the truss or by using a 54 mil ( 1.37 mm) clip angle with two No.10 screws in each leg.

804.3.8 Ceiling and roof diaphragms. Ceiling and roof diaphragms shall be in accordance with this section.

804.3.8.1 At gable endwalls a ceiling diaphragm shall be provided by attaching a minimum 1/2-inch ( 12.7 mm) gypsum board in accordance with Tables 804.3.8(1) and 804.3.8(2) or a minimum 3/8-inch ( 9.5 mm) wood structural panel sheathing, which complies with Section 803, in accordance with Table 804.6(3) to the bottom of ceiling joists or roof trusses and connected to wall framing in accordance with Figures 804.3.8(1) and 804.3.8(2), unless studs are designed as full height without bracing at the ceiling. Flat blocking shall consist of C-shape or track section with a minimum thickness of 33 mils ( 0.84 mm).

The ceiling diaphragm shall be secured with screws spaced at a maximum 6 inches (152 mm) o.c. at panel edges and a maximum 12 inches (305 mm) o.c. in the field. Multiplying the required lengths in Tables 804.3.8(1) and 804.3.8(2) for gypsum board sheathed ceiling diaphragms shall be permitted to be multiplied by 0.35 shall be permitted if all panel edges are blocked. Multiplying the required lengths in Tables 804.3.8(1) and 804.3.8(2) for gypsum board sheathed ceiling diaphragms by 0.9 shall be permitted if all panel edges are secured with screws spaced at 4 inches (102 mm) o.c.

804.3.8.2 Roof diaphragm. A roof diaphragm shall be provided by attaching a minimum of 3/8 inch ( 9.5 mm) wood structural panel which complies with Section 803 to roof rafters or truss top chords in accordance with Table 804.3. Buildings with 3:1 or larger plan aspect ratio and with roof rafter slope (pitch) of 9:12 or larger shall have the roof rafters and ceiling joists blocked in accordance with Figure 804.3.8(3).

804.3.9 Roof tie-down. Roof assemblies subject to wind uplift pressures of 20 pounds per square foot ( 0.96 kPa) or greater, as established in Table 301.2(2), shall have rafter-to-bearing wall ties provided in accordance with Table 802.11.

TABLE 804.3.3.2

HIP MEMBER SIZES, 33 ksi STEEL

BUILDING WIDTH (feet) HIP MEMBER DESIGNATIONa
Equivalent ground snow load (psf)
0 to 20 21 to 30 31 to 50 51 to 70
24 800S162-68 800T150-68 800S162-68 800T150-68 800S162-97 800T150-97 1000S162-97 1000T150-97
28 1000S162-68 1000T150-68 1000S162-68 1000T150-68 1000S162-97 1000T150-97 1200S162-97 1200T150-97
32 1000S162-97 1000T150-97 1000S162-97 1000T150-97 1200S162-97 1200T150-97 -
36 1200S162-97 1200T150-97 - - -
40 - - - -

For SI: 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. The web depth of the roof rafters and jack rafters is to match at the hip or they shall be installed in accordance with an approved design.

TABLE 804.3.3.3

HIP SUPPORT COLUMN SIZES

BUILDING WIDTH (feet) HIP SUPPORT COLUMN DESIGNATIONa,b
Equivalent ground snow load (psf)
0 to 20 21 to 30 31 to 50 51 to 70
24 2-350S162-33 2-350S162-33 2-350S162-43 2-350S162-54
28 2-350S162-54 2-550S162-54 2-550S162-68 2-550S162-68
32 2-550S162-68 2-550S162-68 2-550S162-97 -
36 2-550S162-97 - - -
40 - - - -

For SI: 1 foot = 304,8 mm, 1 pound per square foot = 0.0479 kPa.

a. Box shape column only in accordance with Figure 804.3.3.4(2).

b. 33 ksi steel for 33 and 43 mil material; 50 ksi steel for thicker material.

TABLE 804.3.3.4(1)

UPLIFT STRAP CONNECTION REQUIREMENTS HIP SUPPORT COLUMN AT CEILING LINE

BUILDING WIDTH (feet) BASIC WIND SPEED (mph) EXPOSURE B
85 100 110 - -
BASIC WIND SPEED (mph) EXPOSURE C
- 85 - 100 110
Number of No. 10 screws in each end of each 3 inch by 54-mil steel strapa, b, c
24 3 4 4 6 7
28 4 6 6 8 10
32 5 8 8 11 13
36 7 10 11 14 17
40 - - - - -

For SI: 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mil = 0.0254 mm.

a. Two straps are required, one each side of the column.

b. Space screws at 3/4 inch on-center and provide 3/4 inch end distance.

c. 50 ksi steel strap.


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TABLE 804.3.3.4(2)

CONNECTION REQUIREMENTS HIP MEMBER TO HIP SUPPORT COLUMN

BUILDING WIDTH (feet) NUMBER OF NO. 10 SCREWS IN EACH FRAMING ANGLEa, b, c
Equivalent ground snow load (psf)
0 to 20 21 to 30 31 to 50 51 to 70
24 10 10 10 12
28 10 10 14 18
32 10 12 - -
36 14 - - -
40 - - - -

For SI: 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Screws to be divided equally between the connection to the hip member and the column. Refer to Figures 804.3.3.4(3) and 804.3.3.4(4).

b. The number of screws required in each framing angle is not to be less than shown in Table 804.3.3.4(1).

c. 50 ksi steel from the framing angle.


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                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20120529_1331-14.jpg

TABLE 804.3.3.4(3)

UPLIFT STRAP CONNECTION REQUIREMENTS HIP MEMBER TO WALL

BUILDING WIDTH (feet) BASIC WIND SPEED (mph) EXPOSURE B
85 100 110 - -
BASIC WIND SPEED (mph) EXPOSURE C
- 85 - 100 110
Number of No. 10 screws in each end of each 3 inch by 54-mil Steel strapa,b,c
24 2 2 3 3 4
28 2 3 3 4 5
32 3 4 4 6 7
36 3 5 5 7 8
40 - - - - -

For SI: 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Two straps are required, one each side of the column.

b. Space screws at 3/4 inches on-center and provide 3/4 inch end distance.

c. 50 ksi steel strap.


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20120529_1331-15.jpg


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20120529_1331-16.jpg


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TABLE 804.3.8(1)

REQUIRED LENGTHS FOR CEILING DIAPHRAGMS AT GABLE ENDWALLS GYPSUM BOARD SHEATHED, CEILING HEIGHT = 8 FT a,b,c,d,e,f

Exposure B BASIC WIND SPEED (mph)
85 100 110 - -
Exposure C - 85 - 100 110
Roof pitch Building endwall width (feet) Minimum diaphragm length (feet)
3:12 to 6:12 24 - 28 14 20 22 28 32
28 - 32 16 22 28 32 38
32 - 36 20 26 32 38 44
36 - 40 22 30 36 44 50
6:12 to 9:12 24 - 28 16 22 26 32 36
28 - 32 20 26 32 38 44
32 - 36 22 32 38 44 52
36 - 40 26 36 44 52 60
9:12 to 12:12 24 - 28 18 26 30 36 42
28 - 32 22 30 36 42 50
32 - 36 26 36 42 50 60
36 - 40 30 42 50 60 70

For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s, 1 foot = 304.8 mm, 1 mil = 0.0254 mm.

a. Ceiling diaphragm is composed of 1/2 inch gypsum board (min. thickness) secured with screws spaced at 6 inches o.c. at panel edges and 12 inches o.c. in field. Use No. 8 screws (min.) when framing members have a designation thickness of 54 mils or less and No. 10 screws (min.) when framing members have a designation thickness greater than 54 mils.

b. Maximum aspect ratio (length/width) of diaphragms is 2:1.

c. Building width is in the direction of horizontal framing members supported by the wall studs.

d. Required diaphragm lengths are to be provided at each end of the structure.

e. Multiplying required diaphragm lengths by 0.35 is permitted if all panel edges are blocked.

f. Multiplying required diaphragm lengths by 0.9 is permitted if all panel edges are secured with screws spaced at 4 inches o.c.


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TABLE 804.3.8(2)

REQUIRED LENGTHS FOR CEILING DIAPHRAGMS AT GABLE ENDWALLS GYPSUM BOARD SHEATHED CEILING HEIGHT = 9 OR 10 FTa,b,c,d,e,f

Exposure B BASIC WIND SPEED (mph)
85 100 110 - -
Exposure C - 85 - 100 110
Roof pitch Building endwall width (feet) Minimum diaphragm length (feet)
3:12 to 6:12 24 - 28 16 22 26 32 38
28 - 32 20 26 32 38 44
32 - 36 22 30 36 44 50
36 - 40 26 36 42 50 58
6:12 to 9:12 24 - 28 18 26 30 36 42
28 - 32 22 30 36 42 50
32 - 36 26 36 42 50 58
36 - 40 30 42 48 58 68
9:12 to 12:12 24 - 28 20 28 34 40 46
28 - 32 24 34 40 48 56
32 - 36 28 40 48 56 66
36 - 40 34 46 56 66 78

For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.0479 kPa, 1 mph = 0.447 m/s, 1 foot = 304.8 mm, 1 mil = 0.0254 mm.

a. Ceiling diaphragm is composed of 1/2 inch gypsum board (min. thickness) secured with screws spaced at 6 inches o.c. at panel edges and 12 inches o.c. in field. Use No. 8 screws (min.) when framing members have a designation thickness of 54 mils or less and No. 10 screws (min.) when framing members have a designation thickness greater than 54 mils.

b. Maximum aspect ratio (length/width) of diaphragms is 2:1.

c. Building width is in the direction of horizontal framing members supported by the wall studs.

d. Required diaphragm lengths are to be provided at each end of the structure.

e. Required diaphragm lengths are permitted to be multiplied by 0.35 if all panel edges are blocked.

f. Required diaphragm lengths are permitted to be multiplied by 0.9 if all panel edges are secured with screws spaced at 4 inches o.c.


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TABLE 804.3.8(3)

REQUIRED LENGTHS FOR CEILING DIAPHRAGMS AT GABLE ENDWALLS WOOD STRUCTURAL PANEL SHEATHED CEILING HEIGHT = 8, 9 OR 10 FTa,b,c,d

Exposure B BASIC WIND SPEED (mph)
85 100 110 - -
Exposure C - 85 - 100 110
Roof pitch Building endwall width (feet) Minimum diaphragm length (feet)
3:12 to 6:12 24 - 28 10 10 10 10 10
28 - 32 12 12 12 12 12
32 - 36 12 12 12 12 12
36 - 40 14 14 14 14 14
6:12 to 9:12 24 - 28 10 10 10 10 10
28 - 32 12 12 12 12 12
32 - 36 12 12 12 12 12
36 - 40 14 14 14 14 14
9:12 to 12:12 24 - 28 10 10 10 10 10
28 - 32 12 12 12 12 12
32 - 36 12 12 12 12 12
36 - 40 14 14 14 14 14

For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s, 1 foot = 304.8 mm, 1 mil = 0.0254 mm.

a. Ceiling diaphragm is composed of 3/8 inch wood structural panel sheathing (min. thickness) secured with screws spaced at 6 inches o.c. at panel edges and in field. Use No. 8 screws (min.) when framing members have a designation thickness of 54 mils or less and No. 10 screws (min.) when framing members have a designation thickness greater than 54 mils.

b. Maximum aspect ratio (length/width) of diaphragms is 3:1.

c. Building width is in the direction of horizontal framing members supported by the wall studs.

d. Required diaphragm lengths are to be provided at each end of the structure.


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20120529_1331-20.jpg

SECTION 805

CEILING FINISHES

805.1 Ceiling installation. Ceilings shall be installed in accordance with the requirements for interior wall finishes as provided in Section 702.

SECTION 806

ROOF VENTILATION

806.1 Ventilation required. Enclosed attics and enclose drafter spaces formed where ceilings are applied directly to the underside of roof rafters shall have cross ventilation for each separate space by ventilating openings protected against the entrance of rain or snow. Ventilation openings shall have a least dimension of 1/16 inch ( 1.6 mm) minimum and 1/4 inch ( 6.4 mm) maximum. Ventilation openings having a least dimension larger than 1/4 inch ( 6.4 mm) shall be provided with corrosion-resistant wire cloth screening, hardware cloth, or similar material with openings having a least dimension of 1/16 inch ( 1.6 mm) minimum and 1/4 inch ( 6.4 mm) maximum. Openings in roof framing members shall conform to the requirements of Section 802.7.

806.2 Minimum area. The total net free ventilating area shall not be less than 1/150 of the area of the space ventilated except that reduction of the total area to 1/300 is permitted provided that at least 50 percent and not more than 80 percent of the required ventilating area is provided by ventilators located in the upper portion of the space to be ventilated at least 3 feet (914 mm) above the eave or cornice vents with the balance of the required ventilation provided by eave or cornice vents. As an alternative, the net free cross-ventilation area may be reduced to 1/300 when a Class I or II vapor barrier is installed on the warm-in-winter side of the ceiling.

806.3 Vent and insulation clearance. Where eave or cornice vents are installed, insulation shall not block the free flow of air. A minimum of a 1-inch (25 mm) space shall be provided between the insulation and the roof sheathing and at the location of the vent.

806.4 Unvented attic assemblies. Unvented attic assemblies (spaces between the ceiling joists of the top story and the roof rafters) shall be permitted if all the following conditions are met:

1. The unvented attic space is completely contained within the building thermal envelope.

2. No interior vapor retarders are installed on the ceiling side (attic floor) of the unvented attic assembly.

3. Where wood shingles or shakes are used, a minimum 1/4 inch (6 mm) vented air space separates the shingles or shakes and the roofing underlayment above the structural sheathing.

4. In climate zones 5, 6, 7 and 8, any air-impermeable insulation shall be a vapor retarder, or shall have a vapor retarder coating or covering in direct contact with the underside of the insulation.

5. Either Items 5.1, 5.2 or 5.3 shall be met, depending on the air permeability of the insulation directly under the structural roof sheathing.

5.

1. Air-impermeable insulation only. Insulation shall be applied in direct contact with the underside of the structural roof sheathing.

5.

2. Air-permeable insulation only. In addition to the air-permeable installed directly below the structural sheathing, rigid board or sheet insulation shall be installed directly above the structural roof sheathing as specified in Table 806.4 for condensation control.

5.

3. Air-impermeable and air-permeable insulation. The air-impermeable insulation shall be applied in direct contact with the underside of the structural roof sheathing as specified in Table 806.4 for condensation control. The air-permeable insulation shall be installed directly under the air-impermeable insulation.

SECTION 807

ATTIC ACCESS

807.1 Attic access. Buildings with combustible ceiling or roof construction shall have an attic access opening to attic areas that exceed 30 square feet ( 2.8 m2) and have a vertical height of 30 inches (762 mm) or greater. The vertical height shall be measured from the top of the ceiling framing members to the underside of the roof framing members.

The rough-framed opening shall not be less than 22 inches by 30 inches (559 mm by 762 mm) and shall be located in a hallway or other readily accessible location. When located in a wall, the opening shall be a minimum of 22 inches wide by 30 inches high. When the access is located in a ceiling, minimum unobstructed headroom in the attic space shall be 30 inches (762 mm) at some point above the access measured vertically from the bottom of ceiling framing members. See Section M1305.1.3 for access requirements where mechanical equipment is located in attics.

TABLE 806.4

INSULATION FOR CONDENSATION CONTROL

CLIMATE ZONE MINIMUM RIGID BOARD ON AIR-IMPERMEABLE INSULATION R-VALUEa
2B and 3B tile roof only 0 (none required)
1, 2A, 2B, 3A, 3B, 3C R-5
4C R-10
4A, 4B R-15
5 R-20
6 R-25
7 R-30
8 R-35

a. Contributes to but does not supersede Chapter 11 energy requirements.

Effective: 01/01/2013
R.C. 119.032 review dates: 01/01/2018
Promulgated Under: 119.03
Statutory Authority: 3781.10(A)
Rule Amplifies: 3781.01, 3781.06, 3781.10 , 3781.11, 3791.04, 4740.14

4101:8-8-01 [Effective 7/1/2019] Roof-ceiling construction.

[Comment: When a reference is made within this rule to a federal statutory provision, an industry consensus standard, or any other technical publication, the specific date and title of the publication as well as the name and address of the promulgating agency are listed in rule 4101:8-44-01 of the Administrative Code. The application of the referenced standards shall be limited and as prescribed in section 102.5 of rule 4101:8-1-01 of the Administrative Code.]

SECTION 801

GENERAL

801.1 Application. The provisions of this chapter shall control the design and construction of the roof-ceiling system for buildings.

801.2 Requirements. Roof and ceiling construction shall be capable of accommodating all loads imposed in accordance with Section 301 and of transmitting the resulting loads to the supporting structural elements.

801.3 Roof drainage. In areas where expansive soils or collapsible soils are known to exist, all dwellings shall have a controlled method of water disposal from roofs that will collect and discharge roof drainage to the ground surface not less than 5 feet (1524 mm) from foundation walls or to an approved drainage system.

Exception: The minimum distance shall not apply when the discharge occurs on the exterior side of walls where the building official determines such drainage will not be detrimental to the building performance.

SECTION 802

WOOD ROOF FRAMING

802.1 General. Wood and wood-based products used for load-supporting purposes shall conform to the applicable provisions of this section.

802.1.1 Sawn lumber. Sawn lumber shall be identified by a grade mark of an accredited lumber grading or inspection agency and have design values certified by an accreditation body that complies with DOC PS 20. In lieu of a grade mark, a certificate of inspection issued by a lumber grading or inspection agency meeting the requirements of this section shall be accepted.

802.1.1.1 End-jointed lumber. Approved end-jointed lumber identified by a grade mark conforming to Section 802.1.1 shall be permitted to be used interchangeably with solid-sawn members of the same species and grade. End-jointed lumber used in an assembly required elsewhere in this code to have a fire-resistance rating shall have the designation "Heat-Resistant Adhesive" or "HRA" included in its grade mark.

802.1.2 Structural glued-laminated timbers. Glued-laminated timbers shall be manufactured and identified as required in ANSI A 190.1, ANSI 117 and ASTM D3737.

802.1.3 Structural log members. Structural log members shall comply with the provisions of ICC 400.

802.1.4 Structural composite lumber. Structural capacities for structural composite lumber shall be established and monitored in accordance with ASTM D5456.

802.1.5 Fire-retardant-treated wood. Fire-retardant-treated wood (FRTW) is any wood product that, when impregnated with chemicals by a pressure process or other means during manufacture, shall have, when tested in accordance with ASTM E84 or UL 723, a listed flame spread index of 25 or less and does not show evidence of significant progressive combustion where the test is continued for an additional 20-minute period. In addition, the flame front shall not progress more than 10.5 feet (3200 mm) beyond the center line of the burners at any time during the test.

802.1.5.1 Pressure process. For wood products impregnated with chemicals by a pressure process, the process shall be performed in closed vessels under pressures not less than 50 pounds per square inch gauge (psig) ( 344.7 kPa).

802.1.5.2 Other means during manufacture. For wood products produced by other means during manufacture the treatment shall be an integral part of the manufacturing process of the wood product. The treatment shall provide permanent protection to all surfaces of the wood product.

802.1.5.3 Testing. For wood products produced by other means during manufacture, other than a pressure process, all sides of the wood product shall be tested in accordance with and produce the results required in Section 802.1.5. Testing of only the front and back faces of wood structural panels shall be permitted.

802.1.5.4 Labeling. In addition to the labels required by Section 802.1.1 for sawn lumber and Section 803.2.1 for wood structural panels, each piece of fire-retardant-treated lumber and wood structural panel shall be labeled. The label shall contain:

1. The identification mark of an approved agency in accordance with Section 1703.5 of the Ohio building code.

2. Identification of the treating manufacturer.

3. The name of the fire-retardant treatment.

4. The species of wood treated.

5. Flame spread index and smoke-developed index.

6. Method of drying after treatment.

7. Conformance to applicable standards in accordance with Sections 802.1.5.5 through 802.1.5.10.

8. For FRTW exposed to weather, or a damp or wet location, the words "No increase in the listed classification when subjected to the Standard Rain Test" (ASTM D2898).

802.1.5.5 Strength adjustments. Design values for untreated lumber and wood structural panels as specified in Section 802.1 shall be adjusted for fire-retardant-treated wood. Adjustments to design values shall be based on an approved method of investigation that takes into consideration the effects of the anticipated temperature and humidity to which the fire-retardant-treated wood will be subjected, the type of treatment and redrying procedures.

802.1.5.6 Wood structural panels. The effect of treatment and the method of redrying after treatment, and exposure to high temperatures and high humidities on the flexure properties of fire-retardant-treated softwood plywood shall be determined in accordance with ASTM D5516. The test data developed by ASTM D5516 shall be used to develop adjustment factors, maximum loads and spans, or both for untreated plywood design values in accordance with ASTM D6305. Each manufacturer shall publish the allowable maximum loads and spans for service as floor and roof sheathing for their treatment.

802.1.5.7 Lumber. For each species of wood treated, the effect of the treatment and the method of redrying after treatment and exposure to high temperatures and high humidities on the allowable design properties of fire-retardant-treated lumber shall be determined in accordance with ASTM D5664. The test data developed by ASTM D5664 shall be used to develop modification factors for use at or near room temperature and at elevated temperatures and humidity in accordance with ASTM D6841. Each manufacturer shall publish the modification factors for service at temperatures of not less than 80°F (27°C) and for roof framing. The roof framing modification factors shall take into consideration the climatological location.

802.1.5.8 Exposure to weather. Where fire-retardant-treated wood is exposed to weather or damp or wet locations, it shall be identified as "Exterior" to indicate there is not an increase in the listed flame spread index as defined in Section 802.1.5 when subjected to ASTM D2898.

802.1.5.9 Interior applications. Interior fire-retardant-treated wood shall have a moisture content of not over 28 percent when tested in accordance with ASTM D3201 procedures at 92-percent relative humidity. Interior fire-retardant-treated wood shall be tested in accordance with Section 802.1.5.6 or 802.1.5.7. Interior fire-retardant-treated wood designated as Type A shall be tested in accordance with the provisions of this section.

802.1.5.10 Moisture content. Fire-retardant-treated wood shall be dried to a moisture content of 19 percent or less for lumber and 15 percent or less for wood structural panels before use. For wood kiln dried after treatment (KDAT) the kiln temperatures shall not exceed those used in kiln drying the lumber and plywood submitted for the tests described in Section 802.1.5.6 for plywood and 802.1.5.7 for lumber.

802.1.6 Cross-laminated timber. Cross-laminated timber shall be manufactured and identified as required by ANSI/APA PRG 320.

802.1.7 Engineered wood rim board. Engineered wood rim boards shall conform to ANSI/APA PRR 410 or shall be evaluated in accordance with ASTM D7672. Structural capacities shall be in accordance with ANSI/APA PRR 410 or established in accordance with ASTM D7672. Rim boards conforming to ANSI/APA PRR 410 shall be marked in accordance with that standard.

802.1.8 Prefabricated wood I-joists. Structural capacities and design provisions for prefabricated wood I-joists shall be established and monitored in accordance with ASTM D5055.

802.2 Design and construction. The roof and ceiling assembly shall provide continuous ties across the structure to prevent roof thrust from being applied to the supporting walls. The assembly shall be designed and constructed in accordance with the provisions of this chapter and Figures 606.11(1), 606.11(2) and 606.11(3) or in accordance with AWC NDS.

802.3 Ridge. A ridge board used to connect opposing rafters shall be not less than 1 inch (25 mm) nominal thickness and not less in depth than the cut end of the rafter. Where ceiling joist or rafter ties do not provide continuous ties across the structure, a ridge beam shall be provided and supported on each end by a wall or girder.

802.4 Rafters. Rafters shall be in accordance with this section.

802.4.1 Rafter size. Rafters shall be sized based on the rafter spans in Tables 802.4.1(1) through 802.4.1(8). Rafter spans shall be measured along the horizontal projection of the rafter. For other grades and species and for other loading conditions, refer to the AWC STJR.

TABLE 802.4.1(1)

RAFTER SPANS FOR COMMON LUMBER SPECIES

(Roof live load = 20 psf, ceiling not attached to rafters, L[DELTA] = 180)


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_1.jpg


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_2.jpg

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:

Hc/Hr

Rafter Span Adjustment Factor

1/3

0.67

1/4

0.76

1/5

0.83

1/6

0.90

1/ 7.5 or less

1.00

where: Hc = Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

Hr = Height of roof ridge measured vertically above the top of the rafter support walls.

b. Span exceeds 26 feet in length.

TABLE 802.4.1(2)

RAFTER SPANS FOR COMMON LUMBER SPECIES

(Roof live load = 20 psf, ceiling attached to rafters, L[DELTA] = 240)


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_3.jpg


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_4.jpg

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:

Hc/Hr

Rafter Span Adjustment Factor

1/3

0.67

1/4

0.76

1/5

0.83

1/6

0.90

1/ 7.5 or less

1.00

where: H c= Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

Hr = Height of roof ridge measured vertically above the top of the rafter support walls.

b. Span exceeds 26 feet in length.

TABLE 802.4.1(3)

RAFTER SPANS FOR COMMON LUMBER SPECIES

(Ground snow load = 30 psf, ceiling not attached to rafters, L[DELTA] = 180)


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_5.jpg


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_6.jpg

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:

Hc/Hr

Rafter Span Adjustment Factor

1/3

0.67

1/4

0.76

1/5

0.83

1/6

0.90

1/ 7.5 or less

1.00

where: Hc = Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

Hr = Height of roof ridge measured vertically above the top of the rafter support walls.

b. Span exceeds 26 feet in length.

TABLE 802.4.1(4)

RAFTER SPANS FOR COMMON LUMBER SPECIES

(Ground snow load = 30 psf, ceiling attached to rafters, L[DELTA] = 240)


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_7.jpg


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_8.jpg

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:

Hc/Hr

Rafter Span Adjustment Factor

1/3

0.67

1/4

0.76

1/5

0.83

1/6

0.90

1/ 7.5 or less

1.00

where: Hc = Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

Hr = Height of roof ridge measured vertically above the top of the rafter support walls.

b. Span exceeds 26 feet in length.

TABLE 802.4.1(5)

RAFTER SPANS FOR COMMON LUMBER SPECIES

(Ground snow load = 50 psf, ceiling not attached to rafters, L[DELTA] = 180)


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_9.jpg


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_10.jpg

Check sources for availability of lumber in lengths greater than 20 feet. For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa

a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:

Hc/Hr

Rafter Span Adjustment Factor

1/3

0.67

1/4

0.76

1/5

0.83

1/6

0.90

1/ 7.5 or less

1.00

where:

Hc = Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

Hr= Height of roof ridge measured vertically above the top of the rafter support walls.

b. Span exceeds 26 feet in length.

TABLE 802.4.1(6)

RAFTER SPANS FOR COMMON LUMBER SPECIES

(Ground snow load = 50 psf, ceiling attached to rafters, L[DELTA] = 240)


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_11.jpg


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_12.jpg

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:

Hc/Hr

Rafter Span Adjustment Factor

1/3

0.67

1/4

0.76

1/5

0.83

1/6

0.90

1/ 7.5 or less

1.00

where:

Hc = Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

Hr= Height of roof ridge measured vertically above the top of the rafter support walls.

TABLE 802.4.1(7)

RAFTER SPANS FOR COMMON LUMBER SPECIES

(Ground snow load = 70 psf, ceiling not attached to rafters, L[DELTA] = 180)


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_13.jpg


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_14.jpg

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:

Hc/Hr

Rafter

Span Adjustment Factor

1/3

  

0.67

1/4

  

0.76

1/5

  

0.83

1/6

  

0.90

1/ 7.5 or less

  

1.00

where:

Hc = Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

Hr = Height of roof ridge measured vertically above the top of the rafter support walls.

TABLE 802.4.1(8)

RAFTER SPANS FOR COMMON LUMBER SPECIES

(Ground snow load = 70 psf, ceiling attached to rafters, L[DELTA] = 240)


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_15.jpg


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_16.jpg

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:

Hc/Hr

Rafter Span Adjustment Factor

1/3

0.67

1/4

0.76

1/5

0.83

1/6

0.90

1/ 7.5 or less

1.00

where:

Hc = Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

Hr = Height of roof ridge measured vertically above the top of the rafter support walls.

802.4.2 Framing details. Rafters shall be framed not more than 1½ inches (38 mm) offset from each other to a ridge board or directly opposite from each other with a collar tie, gusset plate or ridge strap in accordance with Table 602.3(1). Rafters shall be nailed to the top wall plates in accordance with Table 602.3(1) unless the roof assembly is required to comply with the uplift requirements of Section 802.11.

802.4.3 Hips and valleys. Hip and valley rafters shall be not less than 2 inches (51 mm) nominal in thickness and not less in depth than the cut end of the rafter. Hip and valley rafters shall be supported at the ridge by a brace to a bearing partition or be designed to carry and distribute the specific load at that point.

802.4.4 Rafter supports. Where the roof pitch is less than 3:12 (25-percent slope), structural members that support rafters, such as ridges, hips and valleys, shall be designed as beams, and bearing shall be provided for rafters in accordance with Section 802.6.

802.4.5 Purlins. Installation of purlins to reduce the span of rafters is permitted as shown in Figure 802.4.5. Purlins shall be sized not less than the required size of the rafters that they support. Purlins shall be continuous and shall be supported by 2-inch by 4-inch (51 mm by 102 mm) braces installed to bearing walls at a slope not less than 45 degrees ( 0.79 rad) from the horizontal. The braces shall be spaced not more than 4 feet (1219 mm) on center and the unbraced length of braces shall not exceed 8 feet (2438 mm).


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_17.jpg

For SI: 1 inch = 25.4 mm, 1 foot = 305 mm, 1 degree = 0.018 rad.

HC= Height of ceiling joists or rafter ties measured vertically above the top of rafter support walls. HR= Height of roof ridge measured vertically above the top of the rafter support walls.

FIGURE 802.4.5

BRACED RAFTER CONSTRUCTION

802.4.6 Collar ties. Where collar ties are used to connect opposing rafters, they shall be located in the upper third of the attic space and fastened in accordance with Table 602.3(1). Collar ties shall be not less than 1 inch by 4 inches (25 mm × 102 mm) nominal, spaced not more than 4 feet (1220 mm) on center. Ridge straps in accordance with Table 602.3(1) shall be permitted to replace collar ties.

802.5 Ceiling joists. Ceiling joists shall be continuous across the structure or securely joined where they meet over interior partitions in accordance with Table 802.5.2.

802.5.1 Ceiling joist size. Ceiling joists shall be sized based on the joist spans in Tables 802.5.1(1) and 802.5.1(2). For other grades and species and for other loading conditions, refer to the AWC STJR.

TABLE 802.5.1(1)

CEILING JOIST SPANS FOR COMMON LUMBER SPECIES

(Uninhabitable attics without storage, live load = 10 psf, L[DELTA] = 240)


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_18.png


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_19.jpg

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Span exceeds 26 feet in length.

TABLE 802.5.1(2)

CEILING JOIST SPANS FOR COMMON LUMBER SPECIES

(Uninhabitable attics with limited storage, live load = 20 psf, L[DELTA] = 240)


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_20.jpg


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_21.jpg

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Span exceeds 26 feet in length.

802.5.2 Ceiling joist and rafter connections. Where ceiling joists run parallel to rafters, they shall be connected to rafters at the top wall plate in accordance with Table 802.5.2. Where ceiling joists are not connected to the rafters at the top wall plate, they shall be installed in the bottom third of the rafter height in accordance with Figure 802.4.5 and Table 802.5.2. Where the ceiling joists are installed above the bottom third of the rafter height, the ridge shall be designed as a beam. Where ceiling joists do not run parallel to rafters, the ceiling joists shall be connected to top plates in accordance with Table 602.3(1). Each rafter shall be tied across the structure with a rafter tie or a 2-inch by 4-inch (51 mm × 102 mm) kicker connected to the ceiling diaphragm with nails equivalent in capacity to Table 802.5.2.

TABLE 802.5.2

RAFTER/CEILING JOIST HEEL JOINT CONNECTIONSa, b, c, d, e, g

RAFTER SLOPE

RAFTER SPACING (inches)

GROUND SNOW LOAD (psf)

20f

30

50

70

Roof span (feet)

12

20

28

36

12

20

28

36

12

20

28

36

12

20

28

36

3:12

  

Required number of 16d common nailsa, bper heel joint splicesc, d, e

12

4

6

8

10

4

6

8

11

5

8

12

15

6

11

15

20

16

5

8

10

13

5

8

11

14

6

11

15

20

8

14

20

26

24

7

11

15

19

7

11

16

21

9

16

23

30

12

21

30

39

4:12

12

3

5

6

8

3

5

6

8

4

6

9

11

5

8

12

15

16

4

6

8

10

4

6

8

11

5

8

12

15

6

11

15

20

24

5

8

12

15

5

9

12

16

7

12

17

22

9

16

23

29

5:12

12

3

4

5

6

3

4

5

7

3

5

7

9

4

7

9

12

16

3

5

6

8

3

5

7

9

4

7

9

12

5

9

12

16

24

4

7

9

12

4

7

10

13

6

10

14

18

7

13

18

23

7:12

12

3

4

4

5

3

3

4

5

3

4

5

7

3

5

7

9

16

3

4

5

6

3

4

5

6

3

5

7

9

4

6

9

11

24

3

5

7

9

3

5

7

9

4

7

10

13

5

9

13

17

9:12

12

3

3

4

4

3

3

3

4

3

3

4

5

3

4

5

7

16

3

4

4

5

3

3

4

5

3

4

5

7

3

5

7

9

24

3

4

6

7

3

4

6

7

3

6

8

10

4

7

10

13

12:12

12

3

3

3

3

3

3

3

3

3

3

3

4

3

3

4

5

16

3

3

4

4

3

3

3

4

3

3

4

5

3

4

5

7

24

3

4

4

5

3

3

4

6

3

4

6

8

3

6

8

10

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. 40d box nails shall be permitted to be substituted for 16d common nails.

b. Nailing requirements shall be permitted to be reduced 25 percent if nails are clinched.

c. Heel joint connections are not required where the ridge is supported by a load-bearing wall, header or ridge beam.

d. Where intermediate support of the rafter is provided by vertical struts or purlins to a load-bearing wall, the tabulated heel joint connection requirements shall be permitted to be reduced proportionally to the reduction in span.

e. Equivalent nailing patterns are required for ceiling joist to ceiling joist lap splices.

f. Applies to roof live load of 20 psf or less.

g. Tabulated heel joint connection requirements assume that ceiling joists or rafter ties are located at the bottom of the attic space. Where ceiling joists or rafter ties are located higher in the attic, heel joint connection requirements shall be increased by the following factors:

HC/HR

Heel Joint Connection Adjustment Factor

1/3

1.5

1/4

1.33

1/5

1.25

1/6

1.2

1/ 7.5 or less

1.11

where:

Hc = Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

HR= Height of roof ridge measured vertically above the top of the rafter support walls.

802.5.2.1 Ceiling joists lapped. Ends of ceiling joists shall be lapped not less than 3 inches (76 mm) or butted over bearing partitions or beams and toenailed to the bearing member. Where ceiling joists are used to provide resistance to rafter thrust, lapped joists shall be nailed together in accordance with Table 802.5.2 and butted joists shall be tied together in a manner to resist such thrust. Joists that do not resist thrust shall be permitted to be nailed in accordance with Table 602.3(1). Wood structural panel roof sheathing, in accordance with Table 503.2.1.1(1), shall not cantilever more than 9 inches (229 mm) beyond the gable endwall unless supported by gable overhang framing.

802.5.2.2 Rafter ties. Wood rafter ties shall be not less than 2 inches by 4 inches (51 mm × 102 mm) installed in accordance with Table 802.5.2 at each rafter. Other approved rafter tie methods shall be permitted.

802.5.2.3 Blocking. Blocking shall be not less than utility grade lumber.

802.6 Bearing. The ends of each rafter or ceiling joist shall have not less than 1½ inches (38 mm) of bearing on wood or metal and not less than 3 inches (76 mm) on masonry or concrete. The bearing on masonry or concrete shall be direct, or a sill plate of 2-inch (51 mm) minimum nominal thickness shall be provided under the rafter or ceiling joist. The sill plate shall provide a minimum nominal bearing area of 48 square inches (30 865 mm2).

802.6.1 Finished ceiling material. If the finished ceiling material is installed on the ceiling prior to the attachment of the ceiling to the walls, such as in construction at a factory, a compression strip of the same thickness as the finished ceiling material shall be installed directly above the top plate of bearing walls if the compressive strength of the finished ceiling material is less than the loads it will be required to withstand. The compression strip shall cover the entire length of such top plate and shall be not less than one-half the width of the top plate. It shall be of material capable of transmitting the loads transferred through it.

802.7 Cutting, drilling and notching. Structural roof members shall not be cut, bored or notched in excess of the limitations specified in this section.

802.7.1 Sawn lumber. Cuts, notches and holes in solid lumber joists, rafters, blocking and beams shall comply with the provisions of Section 502.8.1 except that cantilevered portions of rafters shall be permitted in accordance with Section 802.7.1.1.

802.7.1.1 Cantilevered portions of rafters. Notches on cantilevered portions of rafters are permitted provided the dimension of the remaining portion of the rafter is not less than 3½ inches (89 mm) and the length of the cantilever does not exceed 24 inches (610 mm) in accordance with Figure 802.7.1.1.


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_22.jpg

For SI: 1 inch = 25.4 mm.

FIGURE 802.7.1.1

RAFTER NOTCH

802.7.1.2 Ceiling joist taper cut. Taper cuts at the ends of the ceiling joist shall not exceed one-fourth the depth of the member in accordance with Figure 802.7.1.2.


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_23.jpg

FIGURE 802.7.1.2

CEILING JOIST TAPER CUT

802.7.2 Engineered wood products. Cuts, notches and holes bored in trusses, structural composite lumber, structural glue-laminated members, cross-laminated timber members or I-joists are prohibited except where permitted by the manufacturer's recommendations or where the effects of such alterations are specifically considered in the design of the member by a registered design professional.

802.8 Lateral support. Roof framing members and ceiling joists having a depth-to-thickness ratio exceeding 5 to 1 based on nominal dimensions shall be provided with lateral support at points of bearing to prevent rotation. For roof rafters with ceiling joists attached in accordance with Table 602.3(1), the depth-to-thickness ratio for the total assembly shall be determined using the combined thickness of the rafter plus the attached ceiling joist. Exception: Roof trusses shall be braced in accordance with Section 802.10.3.

802.8.1 Bridging. Rafters and ceiling joists having a depth-to-thickness ratio exceeding 6 to 1 based on nominal dimensions shall be supported laterally by solid blocking, diagonal bridging (wood or metal) or a continuous 1-inch by 3-inch (25 mm by 76 mm) wood strip nailed across the rafters or ceiling joists at intervals not exceeding 8 feet (2438 mm).

802.9 Framing of openings. Openings in roof and ceiling framing shall be framed with header and trimmer joists. Where the header joist span does not exceed 4 feet (1219 mm), the header joist shall be permitted to be a single member the same size as the ceiling joist or rafter. Single trimmer joists shall be permitted to be used to carry a single header joist that is located within 3 feet (914 mm) of the trimmer joist bearing. Where the header joist span exceeds 4 feet (1219 mm), the trimmer joists and the header joist shall be doubled and of sufficient cross section to support the ceiling joists or rafter framing into the header. Approved hangers shall be used for the header joist to trimmer joist connections where the header joist span exceeds 6 feet (1829 mm). Tail joists over 12 feet (3658 mm) long shall be supported at the header by framing anchors or on ledger strips not less than 2 inches by 2 inches (51 mm by 51 mm).

802.10 Wood trusses.

802.10.1 Truss design drawings. Truss design drawings, prepared in conformance to Section 802.10.1, shall be provided to the building official and approved prior to installation. Truss design drawings shall be provided with the shipment of trusses delivered to the job site. Truss design drawings shall include, at a minimum, the following information:

1. Slope or depth, span and spacing.

2. Location of all joints.

3. Required bearing widths.

4. Design loads as applicable.

4.1. Top chord live load (as determined from Section 301.6 ).

4.2. Top chord dead load.

4.3. Bottom chord live load.

4.4. Bottom chord dead load.

4.5. Concentrated loads and their points of application.

4.6. Controlling wind and earthquake loads.

5. Adjustments to lumber and joint connector design values for conditions of use.

6. Each reaction force and direction.

7. Joint connector type and description such as size, thickness or gage and the dimensioned location of each joint connector except where symmetrically located relative to the joint interface.

8. Lumber size, species and grade for each member.

9. Connection requirements for:

9.1. Truss to girder-truss.

9.2. Truss ply to ply.

9.3. Field splices.

10. Calculated deflection ratio or maximum description for live and total load.

11. Maximum axial compression forces in the truss members to enable the building designer to design the size, connections and anchorage of the permanent continuous lateral bracing. Forces shall be shown on the truss design drawing or on supplemental documents.

12. Required permanent truss member bracing location.

802.10.2 Design. Wood trusses shall be designed in accordance with accepted engineering practice. The design and manufacture of metal-plate-connected wood trusses shall comply with ANSI/TPI 1. The truss design drawings shall bear the identification the person primarily responsible for their preparation and include all loads, reactions and calculations used in the design or be prepared by a registered design professional. The truss design drawings shall comply with the requirements of this Section and be in accordance with Section 106.1.

802.10.2.1 Applicability limits. The provisions of this section shall control the design of truss roof framing where snow controls for buildings that are not greater than 60 feet (18 288 mm) in length perpendicular to the joist, rafter or truss span, not greater than 36 feet (10 973 mm) in width parallel to the joist, rafter or truss span, not more than three stories above grade plane in height, and have roof slopes not smaller than 3:12 (25-percent slope) or greater than 12:12 (100-percent slope). Truss roof framing constructed in accordance with the provisions of this section shall be limited to sites subjected to a maximum design wind speed of 140 miles per hour (63 m/s), Exposure B or C, and a maximum ground snow load of 70 psf (3352 Pa). For consistent loading of all truss types, roof snow load is to be computed as: 0.7pg.

802.10.3 Bracing. Trusses shall be braced to prevent rotation and provide lateral stability in accordance with the requirements specified in the construction documents for the building and on the individual truss design drawings. In the absence of specific bracing requirements, trusses shall be braced in accordance with accepted industry practice such as the "SBCA Building Component Safety Information (BCSI) Guide to Good Practice for Handling, Installing & Bracing of Metal Plate Connected Wood Trusses".

802.10.4 Alterations to trusses. Truss members shall not be cut, notched, drilled, spliced or otherwise altered in any way without the approval of a registered design professional. Alterations resulting in the addition of load such as HVAC equipment water heater that exceeds the design load for the truss shall not be permitted without verification that the truss is capable of supporting such additional loading.

802.11 Roof tie-down.

TABLE 802.11

RAFTER OR TRUSS UPLIFT CONNECTION FORCES FROM WIND

(ASD) (POUNDS PER CONNECTION)a, b, c, d, e, f, g, h

RAFTER OR TRUSS SPACING

ROOF SPAN (feet)

EXPOSURE B

Ultimate Design Wind Speed Vult (mph)

110

115

120

130

140

Roof Pitch

Roof Pitch

Roof Pitch

Roof Pitch

Roof Pitch

     

< 5:12

> 5:12

< 5:12

> 5:12

< 5:12

>5:12

< 5:12

>5:12

< 5:12

>5:12

12" o.c.

12

48

43

59

53

70

64

95

88

122

113

18

59

52

74

66

89

81

122

112

157

146

24

71

62

89

79

108

98

149

137

192

178

28

79

69

99

88

121

109

167

153

216

200

32

86

75

109

97

134

120

185

170

240

222

36

94

82

120

106

146

132

203

186

264

244

42

106

92

135

120

166

149

230

211

300

278

48

118

102

151

134

185

166

258

236

336

311

16" o.c.

12

64

57

78

70

93

85

126

117

162

150

18

78

69

98

88

118

108

162

149

209

194

24

94

82

118

105

144

130

198

182

255

237

28

105

92

132

117

161

145

222

203

287

266

32

114

100

145

129

178

160

246

226

319

295

36

125

109

160

141

194

176

270

247

351

325

42

141

122

180

160

221

198

306

281

399

370

48

157

136

201

178

246

221

343

314

447

414

24" o.c.

12

96

86

118

106

140

128

190

176

244

226

18

118

104

148

132

178

162

244

224

314

292

24

142

124

178

158

216

196

298

274

384

356

28

158

138

198

176

242

218

334

306

432

400

32

172

150

218

194

268

240

370

340

480

444

36

188

164

240

212

292

264

406

372

528

488

42

212

184

270

240

332

298

460

422

600

556

48

236

204

302

268

370

332

516

472

672

622

12" o.c.

12

95

88

110

102

126

118

161

151

198

186

18

121

111

141

131

163

151

208

195

257

242

24

148

136

173

160

200

185

256

239

317

298

28

166

152

195

179

225

208

289

269

358

335

32

184

168

216

199

249

231

321

299

398

373

36

202

185

237

219

274

254

353

329

438

411

42

229

210

269

248

312

289

402

375

499

468

16" o.c.

48

256

234

302

278

349

323

450

420

560

524

12

126

117

146

136

168

157

214

201

263

247

18

161

148

188

174

217

201

277

259

342

322

24

197

181

230

213

266

246

340

318

422

396

28

221

202

259

238

299

277

384

358

476

446

32

245

223

287

265

331

307

427

398

529

496

36

269

246

315

291

364

338

469

438

583

547

42

305

279

358

330

415

384

535

499

664

622

48

340

311

402

370

464

430

599

559

745

697

24" o.c.

12

190

176

220

204

252

236

322

302

396

372

18

242

222

282

262

326

302

416

390

514

484

24

296

272

346

320

400

370

512

478

634

596

28

332

304

390

358

450

416

578

538

716

670

32

368

336

432

398

498

462

642

598

796

746

36

404

370

474

438

548

508

706

658

876

822

42

458

420

538

496

624

578

804

750

998

936

48

512

468

604

556

698

646

900

840

1120

1048

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s, 1 pound = 0.454 kg, 1 pound per square foot = 47.9 N/m2, 1 pound per linear foot = 14.6 N/m.

a. The uplift connection forces are based on a maximum 33-foot mean roof height and Wind Exposure Category B or C. For Exposure D, the uplift connection force shall be selected from the Exposure C portion of the table using the next highest tabulated ultimate design wind speed. The adjustment coefficients in Table 301.2(3) shall not be used to multiply the tabulated forces for Exposures C and D or for other mean roof heights.

b. The uplift connection forces include an allowance for roof and ceiling assembly dead load of 15 psf.

c. The tabulated uplift connection forces are limited to a maximum roof overhang of 24 inches.

d. The tabulated uplift connection forces shall be permitted to be multiplied by 0.75 for connections not located within 8 feet of building corners.

e. For buildings with hip roofs with 5:12 and greater pitch, the tabulated uplift connection forces shall be permitted to be multiplied by 0.70. This reduction shall not be combined with any other reduction in tabulated forces.

f. For wall-to-wall and wall-to-foundation connections, the uplift connection force shall be permitted to be reduced by 60 plf for each full wall above.

g. Linear interpolation between tabulated roof spans and wind speeds shall be permitted.

h. The tabulated forces for a 12-inch on-center spacing shall be permitted to be used to determine the uplift load in pounds per linear foot.

802.11.1 Uplift resistance. Roof assemblies shall have uplift resistance in accordance with Sections 802.11.1.1 and 802.11.1.2.

Where the uplift force does not exceed 200 pounds ( 90.8 kg), rafters and trusses spaced not more than 24 inches (610 mm) on center shall be permitted to be attached to their supporting wall assemblies in accordance with Table 602.3(1).

Where the basic wind speed does not exceed 115 mph, the wind exposure category is B, the roof pitch is 5:12 (42-percent slope) or greater, and the roof span is 32 feet (9754 mm) or less, rafters and trusses spaced not more than 24 inches (610 mm) on center shall be permitted to be attached to their supporting wall assemblies in accordance with Table 602.3(1).

802.11.1.1 Truss uplift resistance. Trusses shall be attached to supporting wall assemblies by connections capable of resisting uplift forces as specified on the truss design drawings for the ultimate design wind speed as determined by Figure 301.2(5) A and listed in Table 301.2(1) or as shown on the construction documents. Uplift forces shall be permitted to be determined as specified by Table 802.11, if applicable, or as determined by accepted engineering practice.

802.11.1.2 Rafter uplift resistance. Individual rafters shall be attached to supporting wall assemblies by connections capable of resisting uplift forces as determined by Table 802.11 or as determined by accepted engineering practice. Connections for beams used in a roof system shall be designed in accordance with accepted engineering practice.

SECTION 803

ROOF SHEATHING

803.1 Lumber sheathing. Allowable spans for lumber used as roof sheathing shall conform to Table 803.1. Spaced lumber sheathing for wood shingle and shake roofing shall conform to the requirements of Sections 905.7 and 905.8.

TABLE 803.1

MINIMUM THICKNESS OF LUMBER ROOF SHEATHING

RAFTER OR BEAM SPACING (inches)

MINIMUM NET THICKNESS (inches)

24

5/8

48a

  

60b

1½ T & G

72c

  

For SI: 1 inch = 25.4 mm.

a. Minimum 270 Fb, 340, 000 E.

b. Minimum 420 Fb, 660, 000 E.

c. Minimum 600 Fb, 1, 150, 000 E.

803.2 Wood structural panel sheathing.

803.2.1 Identification and grade. Wood structural panels shall conform to DOC PS 1, DOC PS 2, CSA O437 or CSA O325, and shall be identified for grade, bond classification and performance category by a grade mark or certificate of inspection issued by an approved agency. Wood structural panels shall comply with the grades specified in Table 503.2.1.1(1).

803.2.1.1 Exposure durability. Wood structural panels, when designed to be permanently exposed in outdoor applications, shall be of an exterior exposure durability. Wood structural panel roof sheathing exposed to the underside shall be permitted to be of interior type bonded with exterior glue, identified as Exposure 1.

803.2.1.2 Fire-retardant-treated plywood. The allowable unit stresses for fire-retardant-treated plywood, including fastener values, shall be developed from an approved method of investigation that considers the effects of anticipated temperature and humidity to which the fire-retardant-treated plywood will be subjected, the type of treatment and redrying process. The fire-retardant-treated plywood shall be graded by an approved agency.

803.2.2 Allowable spans. The maximum allowable spans for wood structural panel roof sheathing shall not exceed the values set forth in Table 503.2.1.1(1), or APA E30.

803.2.3 Installation. Wood structural panel used as roof sheathing shall be installed with joints staggered or not staggered in accordance with Table 602.3(1), APA E30 for wood roof framing or with Table 804.3 for cold-formed steel roof framing. Wood structural panel roof sheathing in accordance with Table 503.2.1.1(1) shall not cantilever more than 9 inches (229 mm) beyond the gable endwall unless supported by gable overhang framing.

SECTION 804

COLD-FORMED STEEL ROOF FRAMING

804.1 General. Elements shall be straight and free of any defects that would significantly affect their structural performance. Cold-formed steel roof framing members shall be in accordance with the requirements of this section.

804.1.1 Applicability limits. The provisions of this section shall control the construction of cold-formed steel roof framing for buildings not greater than 60 feet (18 288 mm) perpendicular to the joist, rafter or truss span, not greater than 40 feet (12 192 mm) in width parallel to the joist span or truss, less than or equal to three stories above grade plane and with roof slopes not less than 3:12 (25-percent slope) or greater than 12:12 (100-percent slope). Cold-formed steel roof framing constructed in accordance with the provisions of this section shall be limited to sites where the ultimate design wind speed is less than 140 miles per hour (63 m/s), Exposure Category B or C, and the ground snow load is less than or equal to 70 pounds per square foot (3350 Pa).

804.1.2 In-line framing. Cold-formed steel roof framing constructed in accordance with Section 804 shall be located in line with load-bearing studs in accordance with Figure 804.1.2 and the tolerances specified as follows:

1. The maximum tolerance shall be¾ inch ( 19.1 mm) between the centerline of the horizontal framing member and the centerline of the vertical framing member.

2. Where the centerline of the horizontal framing member and bearing stiffener are located to one side of the centerline of the vertical framing member, the maximum tolerance shall be1/8 inch ( 3.2 mm) between the web of the horizontal framing member and the edge of the vertical framing member.


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_24.jpg

For SI: 1 inch = 25.4 mm.

FIGURE 804.1.2

IN-LINE FRAMING

804.2 Structural framing. Load-bearing, cold-formed steel roof framing members shall be in accordance with this section.

804.2.1 Material. Load-bearing, cold-formed steel framing members shall be cold formed to shape from structural quality sheet steel complying with the requirements of ASTM A1003, Structural Grades 33 Type H and 50 Type H.

804.2.2 Corrosion protection. Load-bearing, cold-formed steel framing shall have a metallic coating complying with ASTM A1003 and one of the following:

1. Not less than G 60 in accordance with ASTM A653.

2. Not less than AZ 50 in accordance with ASTM A792.

804.2.3 Dimension, thickness and material grade. Load-bearing, cold-formed steel roof framing members shall comply with Figure 804.2.3(1) and with the dimensional and thickness requirements specified in Table 804.2.3. Additionally, C-shaped sections shall have a minimum flange width of 1.625 inches (41 mm) and a maximum flange width of 2 inches (51 mm). The minimum lip size for C-shaped sections shall be½ inch ( 12.7 mm). Tracks shall comply with Figure 804.2.3(2) and shall have a minimum flange width of 1¼ inches (32 mm). Minimum Grade 33 ksi steel shall be used wherever 33 mil and 43 mil thicknesses are specified. Minimum Grade 50 ksi steel shall be used wherever 54 and 68 mil thicknesses are specified.

TABLE 804.2.3

LOAD-BEARING COLD-FORMED STEEL ROOF FRAMING MEMBER SIZES AND THICKNESSES

MEMBER

DESIGNATIONa

WEB DEPTH (inches)

MINIMUM BASE STEEL THICKNESS mil (inches)

350S162-t

3.5

33 ( 0.0329 ), 43 ( 0.0428 ), 54 ( 0.0538 )

550S162-t

5.5

33 ( 0.0329 ), 43 ( 0.0428 ), 54 ( 0.0538 ), 68 ( 0.0677 )

800S162-t

8

33 ( 0.0329 ), 43 ( 0.0428 ), 54 ( 0.0538 ), 68 ( 0.0677 )

1000S162-t

10

43 ( 0.0428 ), 54 ( 0.0538 ), 68 ( 0.0677 )

1200S162-t

12

43 ( 0.0428 ), 54 ( 0.0538 ), 68 ( 0.0677 )

For SI: 1 inch = 25.4 mm a. The member designation is defined by the first number representing the member depth in hundredths of an inch, the letter "s" representing a stud or joist member, the second number representing the flange width in hundredths of an inch and the letter "t" shall be a number representing the minimum base metal thickness in mils.


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_25.jpg

FIGURE 804.2.3(1)

C-SHAPED SECTION


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_26.jpg

FIGURE 804.2.3(2)

TRACK SECTION

804.2.4 Identification. Load-bearing, cold-formed steel framing members shall have a legible label, stencil, stamp or embossment with the following information as a minimum:

1. Manufacturer's identification.

2. Minimum base steel thickness in inches (mm).

3. Minimum coating designation.

4. Minimum yield strength, in kips per square inch (ksi) (MPa).

804.2.5 Fastening requirements. Screws for steel-to-steel connections shall be installed with a minimum edge distance and center-to-center spacing of½ inch ( 12.7 mm), shall be self-drilling tapping and shall conform to ASTM C1513. Structural sheathing shall be attached to cold-formed steel roof rafters with minimum No. 8 self-drilling tapping screws that conform to ASTM C1513. Screws for attaching structural sheathing to cold-formed steel roof framing shall have a minimum head diameter of 0.292 inch ( 7.4 mm) with countersunk heads and shall be installed with a minimum edge distance of3/8 inch ( 9.5 mm). Gypsum board ceilings shall be attached to cold-formed steel joists with minimum No. 6 screws conforming to ASTM C954 or ASTM C1513 with a bugle-head style and shall be installed in accordance with Section 805.

For all connections, screws shall extend through the steel not fewer than three exposed threads. Fasteners shall have rust-inhibitive coating suitable for the installation in which they are being used, or be manufactured from material not susceptible to corrosion.

804.2.6 Web holes, web hole reinforcing and web hole patching. Web holes, web hole reinforcing and web hole patching shall be in accordance with this section.

804.2.6.1 Web holes. Web holes in roof framing members shall comply with all of the following conditions:

1. Holes shall conform to Figure 804.2.6.1.

2. Holes shall be permitted only along the centerline of the web of the framing member.

3. Center-to-center spacing of holes shall be not less than 24 inches (610 mm).

4. The web hole width shall be not greater than one-half the member depth, or 2½ inches (64 mm).

5. Holes shall have a web hole length not exceeding 4½ inches (114 mm).

6. The minimum distance between the edge of the bearing surface and the edge of the web hole shall be not less than 10 inches (254 mm).

Framing members with web holes not conforming to Items 1 though 6 shall be reinforced in accordance with Section 804.2.6.2, patched in accordance with Section 804.2.6.3 or designed in accordance with accepted engineering practices.


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_27.jpg

For SI: 1 inch = 25.4 mm.

FIGURE 804.2.6.1

ROOF FRAMING MEMBER WEB HOLES

804.2.6.2 Web hole reinforcing. Reinforcement of web holes in ceiling joists not conforming to the requirements of Section 804.2.6.1 shall be permitted if the hole is located fully within the center 40 percent of the span and the depth and length of the hole do not exceed 65 percent of the flat width of the web. The reinforcing shall be a steel plate or C-shaped section with a hole that does not exceed the web hole size limitations of Section 804.2.6.1 for the member being reinforced. The steel reinforcing shall be the same thickness as the receiving member and shall extend not less than 1 inch (25 mm) beyond all edges of the hole. The steel reinforcing shall be fastened to the web of the receiving member with No. 8 screws spaced not greater than 1 inch (25 mm) center to center along the edges of the patch with minimum edge distance of½ inch ( 12.7 mm).

804.2.6.3 Hole patching. Patching of web holes in roof framing members not conforming to the requirements in Section 804.2.6.1 shall be permitted in accordance with either of the following methods:

1. Framing members shall be replaced or designed in accordance with accepted engineering practices where web holes exceed either of the following size limits:

1.1. The depth of the hole, measured across the web, exceeds 70 percent of the flat width of the web.

1.2. The length of the hole measured along the web, exceeds 10 inches (254 mm) or the depth of the web, whichever is greater.

2. Web holes not exceeding the dimensional requirements in Section 804.2.6.3, Item 1, shall be patched with a solid steel plate, stud section or track section in accordance with Figure 804.2.6.3. The steel patch shall, as a minimum, be the same thickness as the receiving member and shall extend not less than 1 inch (25 mm) beyond all edges of the hole. The steel patch shall be fastened to the web of the receiving member with No. 8 screws spaced not greater than 1 inch (25 mm) center-to-center along the edges of the patch with minimum edge distance of ½ inch ( 12.7 mm).


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_28.jpg

For SI: 1 inch = 25.4 mm.

FIGURE 804.2.6.3

ROOF FRAMING MEMBER WEB HOLE PATCH


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_29.jpg

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mil = 0.0254 mm.

FIGURE 804.3

COLD-FORMED STEEL ROOF CONSTRUCTION

804.3 Roof construction. Cold-formed steel roof systems constructed in accordance with the provisions of this section shall consist of both ceiling joists and rafters in accordance with Figure 804.3 and fastened in accordance with Table 804.3.

TABLE 804.3

ROOF FRAMING FASTENING SCHEDULEa, b

DESCRIPTION OF BUILDING ELEMENTS

NUMBER AND SIZE OF FASTENERSa

SPACING OF FASTENERS

Roof sheathing

(oriented strand board or plywood) to rafter

No. 8 screws

6" o.c. on edges and 12"o.c. at interior supports.

6"o.c. at gable end truss

Gable end truss to endwall top track

No. 10 screws

12" o.c.

Rafter to ceiling joist

Minimum No. 10 screws, in accordance with Table 804.3.1.1(3)

Evenly spaced, not less than 1/2" from all edges.

  

Ceiling Joist Spacing (in.)

Roof Span (ft)

Ultimate Design Wind Speed (mph) and Exposure Category

  
  

126 B 110 C

<139 B 115 C

126 C

<139 C

  

Ceiling joist or roof truss to top track of bearing wallb

16

24

2

2

2

3

Each ceiling joist or roof truss

28

2

2

3

3

32

2

2

3

4

36

2

2

3

4

40

2

2

3

4

24

24

2

2

3

4

28

2

2

4

5

32

2

3

4

5

36

2

3

4

6

40

2

3

5

6

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mil = 0.0254 mm.

a. Screws are a minimum No. 10 unless noted otherwise.

b. Indicated number of screws shall be applied through the flanges of the truss or ceiling joist or through each leg of a 54 mil clip angle. See Section 804.3.8 for additional requirements to resist uplift forces.

804.3.1 Ceiling joists. Cold-formed steel ceiling joists shall be in accordance with this section.

804.3.1.1 Minimum ceiling joist size. Ceiling joist size and thickness shall be determined in accordance with the limits set forth in Tables 804.3.1.1(1) and 804.3.1.1(2). When determining the size of ceiling joists, the lateral support of the top flange shall be classified as unbraced, braced at midspan or braced at third points in accordance with Section 804.3.1.3. Where sheathing material is attached to the top flange of ceiling joists or where the bracing is spaced closer than at third points of the joists, the "third point" values from Tables 804.3.1.1(1) and 804.3.1.1(2) shall be used.

Ceiling joists shall have a bearing support length of not less than 1½ inches (38 mm) and shall be connected to roof rafters (heel joint) with No. 10 screws in accordance with Figure 804.3.1.1 and Table 804.3.1.1(3).

Where continuous joists are framed across interior bearing supports, the interior bearing supports shall be located within 24 inches (610 mm) of midspan of the ceiling joist, and the individual spans shall not exceed the applicable spans in Tables 804.3.1.1(1) and 804.3.1.1(2).

Where the attic is to be used as an occupied space, the ceiling joists shall be designed in accordance with Section 505.

TABLE 804.3.1.1(1)

CEILING JOIST SPANS 10 PSF LIVE LOAD (NO ATTIC STORAGE)a, b, c, d

MEMBER DESIGNATION

ALLOWABLE SPAN (feet - inches)

Lateral Support of Top (Compression) Flange

Unbraced

Midspan Bracing Ceiling Joist Spacing (inches)

Third-point Bracing

  

16

24

16

24

16

24

350S162-33

916:

8:^6:

11'-10"

9'-10"

11'-10"

10'-4"

350S162-43

10'-4"

9'-3"

12'-10"

11'-3"

12'-10"

11'-3"

350S162-54

11'-1"

9'-11"

13'-9"

12'-0"

13'-9"

12'-0"

350S162-68

12'-2"

10'-10"

14'-9"

12'-10"

14'-9"

12'-10"

550S162-33

10'-11"

9'-10"

15'-7"

12'-0"

16'-10"

12'-0"

550S162-43

11'-8"

10'-6"

16'-10"

14'-10"

18'-4"

16'-0"

550S162-54

12'-7"

11'-3"

18'-0"

16'-2"

19'-4"

17'-2"

550S162-68

13'-7"

12'-1"

19'-3"

17'-3"

20'-6"

18'-5"

800S162-33

-

-

-

-

-

-

800S162-43

13'-1"

11'-9"

18'-9"

16'-9"

21'-2"

18'-7"

800S162-54

13'-11"

12'-6"

20'-1"

18'-1"

21'-5"

20'-5"

800S162-68

14'-11"

13'-4"

21'-4"

19'-2"

22'-9"

21'-9"

1000S162-43

-

-

-

-

-

-

1000S162-54

14'-10"

13'-4"

21'-4"

19'-2"

22'-8"

21'-8"

1000S162-68

15'-10"

14'-3"

22'-9"

20'-5"

24'-3"

23'-3"

1200S162-43

-

-

-

-

-

-

1200S162-54

-

-

-

-

-

-

1200S162-68

16'-8"

14'-11"

23'-11"

21'-7"

25'-5"

24'-5"

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mil = 0.0254 mm, 1 pound per square foot = 0.0479 kPa.

a. Deflection criterion: L/240 for total loads.

b. Ceiling dead load = 5 psf.

c. Minimum Grade 33 ksi steel shall be used for 33 mil and 43 mil thicknesses. Minimum Grade 50 ksi steel shall be used for 54 and 68 mil thicknesses.

d. Listed allowable spans are not applicable for 350S162-33, 550S162-33, 550S162-43 and 800S162-43 continuous joist members.

TABLE 804.3.1.1(2)

CEILING JOIST SPANS 20 PSF LIVE LOAD (LIMITED ATTIC STORAGE)a, b, c, d

MEMBER DESIGNATION

ALLOWABLE SPAN (feet - inches)

Lateral Support of Top (Compression) Flange

Unbraced

Midspan Bracing Ceiling Joist Spacing (inches)

Third-point Bracing

  

16

24

16

24

16

24

350S162-33

8'-0"

6'-5"

9'-2"

7'-5"

9'-11"

7'-5"

350S162-43

8'-11"

7'-8"

10'-9"

8'-9"

10'-0"

9'-6"

350S162-54

9'-7"

8'-7"

11'-7"

10'-2"

11'-7"

10'-2"

350S162-68

10'-4"

9'-3"

12'-5"

10'-10"

12'-5"

10'-10"

550S162-33

9'-5"

6'-11"

10'-5"

6'-11"

10'-5"

6'-11"

550S162-43

10'-2"

9'-2"

14'-2"

11'-8"

15'-2"

11'-8"

550S162-54

10'-10"

9'-9"

15'-7"

14'-0"

16'-7"

14'-5"

550S162-68

11'-8"

10'-5"

16'-7"

14'-10"

17'-9"

15'-6"

800S162-33

-

-

-

-

-

-

800S162-43

11'-4"

10'-2"

16'-1"

11'-0"

16'-6"

11'-0"

800S162-54

12'-0"

10'-10"

17'-4"

15'-7"

18'-7"

17'-7"

800S162-68

12'-10"

11'-6"

18'-6"

16'-7"

19'-11"

18'-11"

1000S162-43

-

-

-

-

-

-

1000S162-54

12'-10"

11'-7"

18'-5"

16'-6"

19'-8"

18'-8"

1000S162-68

13'-8"

12'-3"

19'-8"

17'-9"

21'-1"

20'-1"

1200S162-43

-

-

-

-

-

-

1200S162-54

-

-

-

-

-

-

1200S162-68

14'-5"

12'-11"

20'-9"

18'-7"

22'-0"

21'-0"

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mil = 0.0254 mm, 1 pound per square foot = 0.0479 kPa.

a. Deflection criterion: L/240 for total loads.

b. Ceiling deal load = 5 psf.

c. Minimum Grade 33 ksi steel shall be used for 33 mil and 43 mil thicknesses. Minimum Grade 50 ksi steel shall be used for 54 and 68 mil thicknesses.

d. Listed allowable spans are not applicable for 350S162-33, 350S162-43, 550S162-33, 550S162-43 and 800S162-43 continuous joist members.

TABLE 804.3.1.1(3)

NUMBER OF SCREWS REQUIRED FOR CEILING JOIST TO ROOF RAFTER CONNECTIONa

ROOF SLOPE

NUMBER OF SCREWS

Building width (feet)

24

28

32

36

40

Ground snow load (psf)

20

30

50

70

20

30

50

70

20

30

50

70

20

30

50

70

20

30

50

70

3/12

5

6

9

11

5

7

10

13

6

8

11

15

7

8

13

17

8

9

14

19

4/12

4

5

7

9

4

5

8

10

5

6

9

12

5

7

10

13

6

7

11

14

5/12

3

4

6

7

4

4

6

8

4

5

7

10

5

5

8

11

5

6

9

12

6/12

3

3

5

6

3

4

6

7

4

4

6

8

4

5

7

9

4

5

8

10

7/12

3

3

4

6

3

3

5

7

3

4

6

7

4

4

6

8

4

5

7

9

8/12

2

3

4

5

3

3

5

6

3

4

5

7

3

4

6

8

4

4

6

8

9/12

2

3

4

5

3

3

4

6

3

3

5

6

3

4

5

7

3

4

6

8

10/12

2

2

4

5

2

3

4

5

3

3

5

6

3

3

5

7

3

4

6

7

11/12

2

2

3

4

2

3

4

5

3

3

4

6

3

3

5

6

3

4

5

7

12/12

2

2

3

4

2

3

4

5

2

3

4

5

3

3

5

6

3

4

5

7

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Screws shall be No. 10.


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_30.jpg

For SI: 1 mil = 0.0254 mm.

FIGURE 804.3.1.1

JOIST TO RAFTER CONNECTION

804.3.1.2 Ceiling joist bottom flange bracing. The bottom flanges of ceiling joists shall be laterally braced by the application of gypsum board or continuous steel straps installed perpendicular to the joist run in accordance with one of the following:

1. Gypsum board shall be fastened with No. 6 screws in accordance with Section 702.

2. Steel straps with a minimum size of 1½ inches by 33 mils (38 mm by 0.84 mm) shall be installed at a maximum spacing of 4 feet (1219 mm). Straps shall be fastened to the bottom flange at each joist with one No. 8 screw and shall be fastened to blocking with two No. 8 screws. Blocking shall be installed between joists at a maximum spacing of 12 feet (3658 mm) measured along a line of continuous strapping (perpendicular to the joist run), and at the termination of all straps.

804.3.1.3 Ceiling joist top flange bracing. The top flanges of ceiling joists shall be laterally braced as required by Tables 804.3.1.1(1) and 804.3.1.1(2), in accordance with one of the following:

1. Minimum 33-mil ( 0.84 mm) C-shaped member in accordance with Figure 804.3.1.3(1).

2. Minimum 33-mil ( 0.84 mm) track section in accordance with Figure 804.3.1.3(1).

3. Minimum 33-mil ( 0.84 mm) hat section in accordance with Figure 804.3.1.3(1).

4. Minimum 54-mil ( 1.37 mm) 1½-inch (38 mm) cold-rolled channel section in accordance with Figure 804.3.1.3(1).

5. Minimum 1½-inch by 33-mil (38 mm by 0.84 mm) continuous steel strap in accordance with Figure 804.3.1.3(2).

Lateral bracing shall be installed perpendicular to the ceiling joists and shall be fastened to the top flange of each joist with one No. 8 screw. Blocking shall be installed between joists in line with bracing at a maximum spacing of 12 feet (3658 mm) measured perpendicular to the joists. Ends of lateral bracing shall be attached to blocking or anchored to a stable building component with two No. 8 screws.


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_31.jpg

FIGURE 804.3.1.3(1)

CEILING JOIST TOP FLANGE BRACING WITH C-SHAPED, TRACK

OR COLD-ROLLED CHANNEL


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_32.jpg

For SI: 1 foot = 304.8 mm.

FIGURE 804.3.1.3(2)

CEILING JOIST TOP FLANGE BRACING WITH

CONTINUOUS STEEL STRAP AND BLOCKING

804.3.1.4 Ceiling joist splicing. Splices in ceiling joists shall be permitted, if ceiling joist splices are supported at interior bearing points and are constructed in accordance with Figure 804.3.1.4. The number of screws on each side of the splice shall be the same as required for the heel joint connection in Table 804.3.1.1(3).


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_33.jpg

For SI: 1 inch = 25.4 mm.

FIGURE 804.3.1.4

SPLICED CEILING JOISTS

804.3.2 Roof rafters. Cold-formed steel roof rafters shall be in accordance with this section.

804.3.2.1 Minimum roof rafter sizes.Roof rafter size and thickness shall be determined in accordance with the limits set forth in Table 804.3.2.1(1) based on the horizontal projection of the roof rafter span. For determination of roof rafter sizes, reduction of roof spans shall be permitted where a roof rafter support brace is installed in accordance with Section 804.3.2.2. The reduced roof rafter span shall be taken as the larger of the distances from the roof rafter support brace to the ridge or to the heel measured horizontally.

For the purpose of determining roof rafter sizes in Table 804.3.2.1(1), ultimate design wind speeds shall be converted to equivalent ground snow loads in accordance with Table 804.3.2.1(2). Roof rafter sizes shall be based on the higher of the ground snow load or the equivalent snow load converted from the ultimate design wind speed.

TABLE 804.3.2.1(1)

ROOF RAFTER SPANSa, b, c, d

MEMBER DESIGNATION

ALLOWABLE SPAN MEASURED HORIZONTALLY (feet - inches)

Ground snow load (psf)

20

30

50

70

        

Rafter spac

ing (inches)

        
  

16

24

16

24

16

24

16

24

550S162-33

13'-11"

11'-4"

11'-9"

9'-7"

9'-5"

7'-8"

8'-1"

6'-7"

550S162-43

15'-9"

13'-8"

14'-3"

11'-8"

11'-4"

9'-3"

9'-9"

7'-11"

550S162-54

16'-11"

14'-10"

15'-3"

13'-4"

13'-3"

11'-7"

12'-0"

10'-6"

550S162-68

18'-2"

15'-10"

16'-5"

14'-4"

14'-3"

12'-5"

12'-11"

11'-3"

800S162-33

16'-4"

13'-4"

13'-11"

11'-4"

11'-1"

9'-0"

9'-6"

6'-7"

800S162-43

19'-7"

16'-0"

16'-8"

13'-7"

13'-4"

10'-10"

11'-5"

9'-4"

800S162-54

22'-9"

19'-11"

20'-7"

17'-11"

17'-10"

4'-9"

15'-6"

12'-7"

800S162-68

24'-7"

21'-6"

22'-2"

19'-5"

19'-3"

16'-10"

17'-5"

14'-8"

1000S162-43

22'-2"

18'-1"

18'-10"

15'-4"

15'-1"

12'-4"

12'-11"

10'-7"

1000S162-54

27'-1"

23'-8"

24'-6"

20'-9"

20'-5"

16'-8"

17'-6"

14'-3"

1000S162-68

29'-5"

25'-8"

26'-6"

23'-2"

23'-0"

19'-6"

20'-6"

16'-9"

1200S162-54

31'-3"

27'-0"

28'-1"

22'-11"

22'-6"

18'-4"

19'-4"

15'-9"

1200S162-68

34'-0"

29'-8"

30'-8"

26'-9"

26'-6"

21'-7"

22'-8"

18'-6"

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Table provides maximum horizontal rafter spans in feet and inches for slopes between 3:12 and 12:12.

b. Deflection criteria: L/240 for live loads and L/180 for total loads.

c. Roof dead load = 12 psf.

d. Grade 33 ksi steel is permitted to be used for 33 mil and 43 mil thicknesses. Grade 50 ksi steel shall be used for 54 and 68 mil thicknesses.

TABLE 804.3.2.1(2)

ULTIMATE DESIGN WIND SPEED TO EQUIVALENT SNOW LOAD CONVERSION

ULTIMATE WIND

EQUIVALENT GROUND SNOW LOAD (psf)

SPEED AND EXPOSURE

Roof slope

Exposure

Wind speed (mph)

3:12

4:12

5:12

6:12

7:12

8:12

9:12

10:12

11:12

12:12

B

115

20

20

20

20

30

20

30

30

30

50

120

20

20

20

20

30

30

30

30

30

50

130

20

20

20

20

30

30

30

50

50

50

<140

20

20

20

20

30

50

50

50

50

50

C

115

20

20

20

20

30

30

30

50

50

50

120

20

20

20

20

30

30

50

50

50

50

130

20

20

20

30

30

50

50

50

50

70

<140

30

30

30

50

50

50

70

70

70

-

For SI: 1 mile per hour = 0.447 m/s, 1 pound per square foot = 0.0479 kPa.

804.3.2.1.1 Eave overhang. Eave overhangs shall not exceed 24 inches (610 mm) measured horizontally.

804.3.2.1.2 Rake overhangs. Rake overhangs shall not exceed 12 inches (305 mm) measured horizontally. Outlookers at gable endwalls shall be installed in accordance with Figure 804.3.2.1.2.


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_34.jpg

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.

FIGURE 804.3.2.1.2

GABLE ENDWALL OVERHANG DETAILS

804.3.2.2 Roof rafter support brace. Where used to reduce roof rafter spans in determining roof rafter sizes, a roof rafter support brace shall meet all of the following conditions:

1. Minimum 350S162-33 C-shaped brace member with maximum length of 8 feet (2438 mm).

2. Minimum brace member slope of 45 degrees ( 0.785 rad) to the horizontal.

3. Minimum connection of brace to a roof rafter and ceiling joist with four No.10 screws at each end.

4. Maximum 6 inches (152 mm) between brace/ceiling joist connection and load-bearing wall below.

5. Each roof rafter support brace greater than 4 feet (1219 mm) in length, shall be braced with a supplemental brace having a minimum size of 350S162-33 or 350T162-33 such that the maximum unsupported length of the roof rafter support brace is 4 feet (1219 mm). The supplemental brace shall be continuous and shall be connected to each roof rafter support brace using two No. 8 screws.

804.3.2.3 Roof rafter splice. Roof rafters shall not be spliced.

804.3.2.4 Roof rafter to ceiling joist and ridge member connection.

Roof rafters shall be connected to a parallel ceiling joist to form a continuous tie between exterior walls in accordance with Figure 804.3.1.1 and Table 804.3.1.1(3). Ceiling joists shall be connected to the top track of the load-bearing wall in accordance with Table 804.3, either with the required number of No. 10 screws applied through the flange of the ceiling joist or by using a 54-mil ( 1.37 mm) clip angle with the required number of No.10 screws in each leg. Roof rafters shall be connected to a ridge member with a minimum 2-inch by 2-inch (51 mm by 51 mm) clip angle fastened with No. 10 screws to the ridge member in accordance with Figure 804.3.2.4 and Table 804.3.2.4. The clip angle shall have a steel thickness equivalent to or greater than the roof rafter thickness and shall extend the depth of the roof rafter member to the extent possible. The ridge member shall be fabricated from a C-shaped member and a track section that shall have a minimum size and steel thickness equivalent to or greater than that of adjacent roof rafters and shall be installed in accordance with Figure 804.3.2.4. The ridge member shall extend the full depth of the sloped roof rafter cut.


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_35.jpg

For SI: 1 inch = 25.4 mm.

FIGURE 804.3.2.4

RIDGE MEMBER CONNECTION

TABLE 804.3.2.4

SCREWS REQUIRED AT EACH LEG OF CLIP ANGLE FOR

ROOF RAFTER TO RIDGE MEMBER CONNECTIONa

BUILDING WIDTH (feet)

NUMBER OF SCREWS

Ground snow load (psf)

  

0 to 20

21 to 30

31 to 50

51 to 70

24

2

2

3

4

28

2

3

4

5

32

2

3

4

5

36

3

3

5

6

40

3

4

5

7

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

a. Screws shall be No. 10 minimum.

804.3.2.5 Roof rafter bottom flange bracing. The bottom flanges of roof rafters shall be continuously braced, at a maximum spacing of 8 feet (2440 mm) as measured parallel to the roof rafters, with one of the following members:

1. Minimum 33-mil ( 0.84 mm) C-shaped member.

2. Minimum 33-mil ( 0.84 mm) track section.

3. Minimum 1½-inch by 33-mil (38 mm by 0.84 mm) steel strap.

The bracing element shall be fastened to the bottom flange of each roof rafter with one No. 8 screw and shall be fastened to blocking with two No.

8 screws. Blocking shall be installed between roof rafters in-line with the continuous bracing at a maximum spacing of 12 feet (3658 mm) measured perpendicular to the roof rafters. The ends of continuous bracing shall be fastened to blocking or anchored to a stable building component with two No. 8 screws.

804.3.3 Cutting and notching. Flanges and lips of load-bearing, cold-formed steel roof framing members shall not be cut or notched.

804.3.4 Headers. Roof-ceiling framing above wall openings shall be supported on headers. The allowable spans for headers in load-bearing walls shall not exceed the values set forth in Section 603.6 and Tables 603.6(1) through 603.6(6).

804.3.5 Framing of openings in roofs and ceilings. Openings in roofs and ceilings shall be framed with header and trimmer joists. Header joist spans shall not exceed 4 feet (1219 mm) in length. Header and trimmer joists shall be fabricated from joist and track members having a minimum size and thickness equivalent to the adjacent ceiling joists or roof rafters and shall be installed in accordance with Figures 804.3.5(1) and 804.3.5(2). Each header joist shall be connected to trimmer joists with not less than four 2-inch by 2-inch (51 by 51 mm) clip angles. Each clip angle shall be fastened to both the header and trimmer joists with four No. 8 screws, evenly spaced, through each leg of the clip angle. The steel thickness of the clip angles shall be not less than that of the ceiling joist or roof rafter. Each track section for a built-up header or trimmer joist shall extend the full length of the joist (continuous).


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_36.jpg

For SI: 1 foot = 304.8 mm.

FIGURE 804.3.5(1)

ROOF OR CEILING OPENING


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_37.jpg

For SI: 1 inch = 25.4 mm.

FIGURE 804.3.5(2)

HEADER TO TRIMMER CONNECTION

804.3.6 Roof trusses. Cold-formed steel trusses shall be designed and installed in accordance with AISI S240. In the absence of specific bracing requirements, trusses shall be braced in accordance with accepted industry practices, such as the "SBCA Cold-Formed Steel Building Component Safety Information (CFSBCSI) Guide to Good Practice for Handling, Installing & Bracing of Cold-Formed Steel Trusses". Trusses shall be connected to the top track of the load-bearing wall in accordance with Table 804.3, either with two No. 10 screws applied through the flange of the truss or by using a 54-mil ( 1.37 mm) clip angle with two No. 10 screws in each leg.

804.3.7 Ceiling and roof diaphragms. Ceiling and roof diaphragms shall be in accordance with this section.

804.3.7.1 Ceiling diaphragms. At gable endwalls a ceiling diaphragm shall be provided by attaching a minimum½-inch ( 12.7 mm) gypsum board or a minimum3/8-inch ( 9.5 mm) wood structural panel sheathing, that complies with Section 803, to the bottom of ceiling joists or roof trusses and connected to wall framing in accordance with Figures 804.3.7.1(1) and 804.3.7.1(2), unless studs are designed as full height without bracing at the ceiling. Flat blocking shall consist of C-shaped or track section with a minimum thickness of 33 mils ( 0.84 mm). For a gypsum board sheathed ceiling, the diaphragm length shall be in accordance with Table 804.3.7.1. For a wood structural panel sheathed ceiling, the diaphragm length shall be not less than 12 feet (3658 mm) for building widths less than 36 feet (10 973 mm), or not less than 14 feet (4267 mm) for building widths greater than or equal to 36 feet (10 973 mm). The ceiling diaphragm shall be secured with screws spaced at a maximum 6 inches (152 mm) o.c. at panel edges and a maximum 12 inches (305 mm) o.c. in the field. The required lengths in Table 804.3.7.1 for gypsum board sheathed ceiling diaphragms shall be permitted to be multiplied by 0.35 if all panel edges are blocked. Multiplying the required lengths in Table 804.3.7.1 for gypsum board sheathed ceiling diaphragms by 0.9 shall be permitted if all panel edges are secured with screws spaced at 4 inches (102 mm) o.c.

TABLE 804.3.7.1

REQUIRED LENGTHS FOR CEILING DIAPHRAGMS AT GABLE ENDWALLS GYPSUM BOARD SHEATHED, CEILING HEIGHT = 8 FEETa, b, c, d, e, f, g

EXPOSURE CATEGORY

ULTIMATE DESIGN WIND SPEED (mph)

B

115

120

130

< 140

-

-

C

-

-

115

120

130

< 140

Roof pitch

Building endwall width (feet)

Mini

mum diaphr

agm length

(feet)

     

3:12 to 6:12

24 - 28

16

18

24

26

30

34

> 28 - 32

20

20

26

32

34

40

> 32 - 36

24

26

30

36

42

46

> 36 - 40

26

28

36

40

48

52

6:12 to 9:12

> 24 - 28

20

20

26

30

34

38

> 28 - 32

24

26

30

36

42

46

> 32 - 36

26

30

38

42

48

54

> 36 - 40

30

34

40

50

56

62

9:12 to 12:12

> 24 - 28

22

24

30

34

38

44

> 28 - 32

26

28

36

40

46

52

> 32 - 36

30

32

40

48

54

62

> 36 - 40

36

38

48

56

64

72

For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s, 1 foot = 304.8 mm, 1 mil = 0.0254 mm.

a. Ceiling diaphragm is composed of 1/2-inch gypsum board (min. thickness) secured with screws spaced at 6 inches o.c. at panel edges and 12 inches o.c. infield. Use No. 8 screws (min.) where framing members have a designation thickness of 54 mils or less and No. 10 screws (min.) where framing members have a designation thickness greater than 54 mils.

b. Maximum aspect ratio (length/width) of diaphragms is 2:1.

c. Building width is in the direction of horizontal framing members supported by the wall studs.

d. Required diaphragm lengths are to be provided at each end of the structure.

e. Multiplying required diaphragm lengths by 0.35 is permitted if all panel edges are blocked.

f. Multiplying required diaphragm lengths by 0.9 is permitted if all panel edges are secured with screws spaced at 4 inches o.c.

g. To determine the minimum diaphragm length for buildings with ceiling heights of 9 feet or 10 feet values in this table shall be multiplied by 1.15.


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_38.jpg

For SI: 1 inch = 25.4 mm.

FIGURE 804.3.7.1(1)

CEILING DIAPHRAGM TO GABLE ENDWALL DETAIL


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_39.jpg

For SI: 1 inch = 25.4 mm.

FIGURE 804.3.7.1(2)

CEILING DIAPHRAGM TO SIDEWALL DETAIL

804.3.7.2 Roof diaphragm. A roof diaphragm shall be provided by attaching not less than3/8-inch ( 9.5 mm) wood structural panel that complies with Section 803 to roof rafters or truss top chords in accordance with Table 804.3. Buildings with 3:1 or larger plan aspect ratio and with roof rafter slope (pitch) of 9:12 or larger shall have the roof rafters and ceiling joists blocked in accordance with Figure 804.3.7.2.


                image: oh/admin/2019/4101$8-8-01_ph_ff_n_ru_20181214_1413_40.jpg

For SI: 1 mil = 0.0254 mm, 1 inch = 25.4 mm.

FIGURE 804.3.7.2

ROOF BLOCKING DETAIL

804.3.8 Roof tie-down. Roof assemblies shall be connected to walls below in accordance with Table 804.3. A continuous load path shall be provided to transfer uplift loads to the foundation.

SECTION 805

CEILING FINISHES

805.1 Ceiling installation. Ceilings shall be installed in accordance with the requirements for interior wall finishes as provided in Section 702.

SECTION 806

ROOF VENTILATION

806.1 Ventilation required. Enclosed attics and enclosed rafter spaces formed where ceilings are applied directly to the underside of roof rafters shall have cross ventilation for each separate space by ventilating openings protected against the entrance of rain or snow. Ventilation openings shall have a least dimension of1/16 inch ( 1.6 mm) minimum and¼ inch ( 6.4 mm) maximum. Ventilation openings having a least dimension larger than¼ inch ( 6.4 mm) shall be provided with corrosion-resistant wire cloth screening, hardware cloth, perforated vinyl or similar material with openings having a least dimension of1/16 inch ( 1.6 mm) minimum and¼ inch ( 6.4 mm) maximum. Openings in roof framing members shall conform to the requirements of Section 802.7. Required ventilation openings shall open directly to the outside air and shall be protected to prevent the entry of birds, rodents, snakes and other similar creatures.

806.2 Minimum vent area. The minimum net free ventilating area shall be1/150 of the area of the vented space.

Exception: The minimum net free ventilation area shall be1/300 of the vented space provided both of the following conditions are met:

1. Deleted.

2. Not less than 40 percent and not more than 50 percent of the required ventilating area is provided by ventilators located in the upper portion of the attic or rafter space. Upper ventilators shall be located not more than 3 feet (914 mm) below the ridge or highest point of the space, measured vertically. The balance of the required ventilation provided shall be located in the bottom one-third of the attic space. Where the location of wall or roof framing members conflicts with the installation of upper ventilators, installation more than 3 feet (914 mm) below the ridge or highest point of the space shall be permitted.

806.3 Vent and insulation clearance. Where eave or cornice vents are installed, blocking, bridging and insulation shall not block the free flow of air. Not less than a 1-inch (25 mm) space shall be provided between the insulation and the roof sheathing and at the location of the vent.

806.4 Installation and weather protection. Ventilators shall be installed in accordance with manufacturer's instructions. Installation of ventilators in roof systems shall be in accordance with the requirements of Section 903. Installation of ventilators in wall systems shall be in accordance with the requirements of Section 703.1.

806.5 Unvented attic and unvented enclosed rafter assemblies. Unvented attics and unvented enclosed roof framing assemblies created by ceilings that are applied directly to the underside of the roof framing members and structural roof sheathing applied directly to the top of the roof framing members/rafters, shall be permitted where all the following conditions are met:

1. The unvented attic space is completely within the building thermal envelope.

2. Interior Class I vapor retarders are not installed on the ceiling side (attic floor) of the unvented attic assembly or on the ceiling side of the unvented enclosed roof framing assembly.

3. Where wood shingles or shakes are used, a minimum ¼-inch ( 6.4 mm) vented airspace separates the shingles or shakes and the roofing underlayment above the structural sheathing.

4. In Climate Zones 5, any air-impermeable insulation shall be a Class II vapor retarder, or shall have a Class II vapor retarder coating or covering in direct contact with the underside of the insulation.

5. Insulation shall comply with Item 5.3 and Item 5.1:

5.1. Item 5.1.1, 5.1.2, 5.1.3 or 5.1.4 shall be met, depending on the air permeability of the insulation directly under the structural roof sheathing.

5.1.1. Where only air-impermeable insulation is provided, it shall be applied in direct contact with the underside of the structural roof sheathing.

5.1.2. Where air-permeable insulation is installed directly below the structural sheathing, rigid board or sheet insulation shall be installed directly above the structural roof sheathing in accordance with the R-values in Table 806.5 for condensation control.

5.1.3. Where both air-impermeable and air-permeable insulation are provided, the air-impermeable insulation shall be applied in direct contact with the underside of the structural roof sheathing in accordance with Item 5.1.1 and shall be in accordance with the R-values in Table 806.5 for condensation control. The air-permeable insulation shall be installed directly under the air-impermeable insulation.

5.1.4. Alternatively, sufficient rigid board or sheet insulation shall be installed directly above the structural roof sheathing to maintain the monthly average temperature of the underside of the structural roof sheathing above 45°F (7°C). For calculation purposes, an interior air temperature of 68°F (20°C) is assumed and the exterior air temperature is assumed to be the monthly average outside air temperature of the three coldest months.

5.2. Deleted.

5.2.1. Deleted.

5.2.2. Deleted.

5.2.3. Deleted.

5.2.4. Deleted.

5.2.5. Deleted.

5.2.6. Deleted.

5.2.7. Deleted.

5.2.8. Deleted.

5.2.9. Deleted.

5.2.10. Deleted.

5.3. Where preformed insulation board is used as the air-impermeable insulation layer, it shall be sealed at the perimeter of each individual sheet interior surface to form a continuous layer.

TABLE 806.5

INSULATION FOR CONDENSATION CONTROL

CLIMATE ZONE

MINIMUM RIGID BOARD ON AIR-IMPERMEABLE INSULATION R-VALUEa, b

4

R-15

5

R-20

a. Contributes to but does not supersede the requirements in Section N1102.

b. Alternatively, sufficient continuous insulation shall be installed directly above the structural roof sheathing to maintain the monthly average temperature of the underside of the structural roof sheathing above 45°F (7°C). For calculation purposes, an interior air temperature of 68°F (20°C) is assumed and the exterior air temperature is assumed to be the monthly average outside air temperature of the three coldest months.

SECTION 807

ATTIC ACCESS

807.1 Attic access. Buildings with combustible ceiling or roof construction shall have an attic access opening to attic areas that have a vertical height of 30 inches (762 mm) or greater over an area of not less than 30 square feet ( 2.8 m2). The vertical height shall be measured from the top of the ceiling framing members to the underside of the roof framing members. The rough-framed opening shall be not less than 22 inches by 30 inches (559 mm by 762 mm) and shall be located in a hallway or other location with ready access. Where located in a wall, the opening shall be not less than 22 inches wide by 30 inches high (559 mm wide by 762 mm high). Where the access is located in a ceiling, minimum unobstructed headroom in the attic space shall be 30 inches (762 mm) at some point above the access measured vertically from the bottom of ceiling framing members. See Section 1305.1.3 for access requirements where mechanical equipment is located in attics.

Replaces: 4101:8-8-01

Effective: 7/1/2019
Five Year Review (FYR) Dates: 07/01/2024
Promulgated Under: 119.03
Statutory Authority: 3781.10(A)(1)
Rule Amplifies: 3781.01, 4740.14, 3791.04, 3781.11, 3781.10 , 3781.06
Prior Effective Dates: 01/01/2013