Chapter 4101:8-9 Roof Assemblies

4101:8-9-01 [Effective until 7/1/2019] Roof assemblies.

[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 901

GENERAL

901.1 Scope. The provisions of this chapter shall govern the design, materials, construction and quality of roof assemblies.

SECTION 902

ROOF CLASSIFICATION

902.1 Roofing covering materials. Roofs shall be covered with materials as set forth in Sections 904 and 905. Class A, B or C roofing shall be installed in areas designated by law as requiring their use or when the edge of the roof is less than 3 feet (914 mm) from a property line. Classes A, B and C roofing required by this section to be listed shall be tested in accordance with UL 790 or ASTM E 108.

Exceptions:

1. Class A roof assemblies include those with coverings of brick, masonry and exposed concrete roof deck.

2. Class A roof assemblies also include ferrous or copper shingles or sheets, metal sheets and shingles, clay or concrete roof tile, or slate installed on noncombustible decks.

902.2 Fire-retardant-treated shingles and shakes. Fire-retardant-treated wood shakes and shingles shall be treated by impregnation with chemicals by the full-cell vacuum-pressure process, in accordance with AWPA C1. Each bundle shall be marked to identify the manufactured unit and the manufacturer, and shall also be labeled to identify the classification of the material in accordance with the testing required in Section 902.1, the treating company and the quality control agency.

SECTION 903

WEATHER PROTECTION

903.1 General. Roof decks shall be covered with approved roof coverings secured to the building or structure in accordance with the provisions of this chapter. Roof assemblies shall be designed and installed in accordance with this code and the approved manufacturer's installation instructions such that the roof assembly shall serve to protect the building or structure.

903.2 Flashing. Flashings shall be installed in a manner that prevents moisture from entering the wall and roof through joints in copings, through moisture permeable materials and at intersections with parapet walls and other penetrations through the roof plane.

903.2.1 Locations. Flashings shall be installed at wall and roof intersections, wherever there is a change in roof slope or direction and around roof openings. Where flashing is of metal, the metal shall be corrosion resistant with a thickness of not less than 0.019 inch ( 0.5 mm) (No. 26 galvanized sheet).

903.2.2 Crickets and saddles. A cricket or saddle shall be installed on the ridge side of any chimney or penetration more than 30 inches (762 mm) wide as measured perpendicular to the slope. Cricket or saddle coverings shall be sheet metal or of the same material as the roof covering.

903.3 Coping. Parapet walls shall be properly coped with noncombustible, weatherproof materials of a width no less than the thickness of the parapet wall.

903.4 Roof drainage. Unless roofs are sloped to drain over roof edges, roof drains shall be installed at each low point of the roof. Where required for roof drainage, scuppers shall be placed level with the roof surface in a wall or parapet. The scupper shall be located as determined by the roof slope and contributing roof area.

903.4.1 Overflow drains and scuppers. Where roof drains are required, overflow drains having the same size as the roof drains shall be installed with the inlet flow line located 2 inches (51 mm) above the low point of the roof, or overflow scuppers having three times the size of the roof drains and having a minimum opening height of 4 inches (102 mm) shall be installed in the adjacent parapet walls with the inlet flow located 2 inches (51 mm) above the low point of the roof served. The installation and sizing of overflow drains, leaders and conductors shall comply with the plumbing code.

Overflow drains shall discharge to an approved location and shall not be connected to roof drain lines.

903.5 Hail exposure. Hail exposure, as specified in Sections 903.5.1 and 903.5.2, shall be determined using Figure 903.5.

903.5.1 Moderate hail exposure. One or more hail days with hail diameters larger than 1.5 inches (38 mm) in a 20-year period.

903.5.2 Severe hail exposure. One or more hail days with hail diameters larger than or equal to 2.0 inches (51 mm) in a 20-year period.

SECTION 904

MATERIALS

904.1 Scope. The requirements set forth in this section shall apply to the application of roof covering materials specified herein. Roof assemblies shall be applied in accordance with this chapter and the manufacturer's installation instructions. Installation of roof assemblies shall comply with the applicable provisions of Section 905.

904.2 Compatibility of materials. Roof assemblies shall be of materials that are compatible with each other and with the building or structure to which the materials are applied.

904.3 Material specifications and physical characteristics. Roof covering materials shall conform to the applicable standards listed in this chapter. In the absence of applicable standards or where materials are of questionable suitability, testing by an approved testing agency shall be required by the building official to determine the character, quality and limitations of application of the materials.

904.4 Product identification. Roof covering materials shall be delivered in packages bearing the manufacturer's identifying marks and approved testing agency labels when required. Bulk shipments of materials shall be accompanied by the same information issued in the form of a certificate or on a bill of lading by the manufacturer.


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SECTION 905

REQUIREMENTS FOR ROOF COVERINGS

905.1 Roof covering application. Roof coverings shall be applied in accordance with the applicable provisions of this section and the manufacturer's installation instructions. Unless otherwise specified in this section, roof coverings shall be installed to resist the component and cladding loads specified in Table 301.2(2), adjusted for height and exposure in accordance with Table 301.2(3).

905.2 Asphalt shingles. The installation of asphalt shingles shall comply with the provisions of this section.

905.2 Asphalt shingles. The installation of asphalt shingles shall comply with the provisions of this section.

905.2.1 Sheathing requirements. Asphalt shingles shall be fastened to solidly sheathed decks.

905.2.2 Slope. Asphalt shingles shall be used only on roof slopes of two units vertical in 12 units horizontal (2:12) or greater. For roof slopes from two units vertical in 12 units horizontal (2:12) up to four units vertical in 12 units horizontal (4:12), double underlayment application is required in accordance with Section 905.2.7.

905.2.3 Underlayment. Unless otherwise noted, required underlayment shall conform to ASTM D 226 Type I, ASTM D 4869 Type I, or ASTM D 6757.

Self-adhering polymer modified bitumen sheet shall comply with ASTM D 1970.

905.2.4 Asphalt shingles. Asphalt shingles shall comply with ASTM D 225 or D 3462.

905.2.4.1 Wind resistance of asphalt shingles. Asphalt shingles shall be tested in accordance with ASTM D 7158. Asphalt shingles shall meet the classification requirements of Table 905.2.4.1(1) for the appropriate maximum basic wind speed. Asphalt shingle packaging shall bear a label to indicate compliance with ASTM D 7158 and the required classification in Table 905.2.4.1(1).

Exception: Asphalt shingles not included in the scope of ASTM D 7158 shall be tested and labeled to indicate compliance with ASTM D 3161 and the required classification in Table 905.2.4.1(2).

TABLE 905.2.4.1(1)

CLASSIFICATION OF ASPHALT ROOF SHINGLES PER ASTM D 7158

MAXIMUM BASIC WIND SPEED FROM FIGURE 301.2(4) (mph) CLASSIFICATION REQUIREMENT
85 D, G or H
90 D, G or H
100 G or H
110 G or H
120 G or H
130 H
140 H
150 H

For SI: 1 mile per hour = 0.447 m/s.

TABLE 905.2.4.1(2)

CLASSIFICATION OF ASPHALT SHINGLES PER ASTM D 3161

MAXIMUM BASIC WIND SPEED FROM FIGURE 301.2(4) (mph) CLASSIFICATION REQUIREMENT
85 A, D or F
90 A, D or F
100 A, D or F
110 F
120 F
130 F
140 F
150 F

For SI: 1 mile per hour = 0.447 m/s.

905.2.5 Fasteners. Fasteners for asphalt shingles shall be galvanized steel, stainless steel, aluminum or copper roofing nails, minimum 12 gage [ 0.105 inch (3 mm)] shank with a minimum 3/8-inch (10 mm) diameter head, ASTM F 1667, of a length to penetrate through the roofing materials and a minimum of 3/4 inch (19 mm) into the roof sheathing. Where the roof sheathing is less than 3/4 inch (19 mm) thick, the fasteners shall penetrate through the sheathing. Fasteners shall comply with ASTM F 1667.

905.2.6 Attachment. Asphalt shingles shall have the minimum number of fasteners required by the manufacturer, but not less than four fasteners per strip shingle or two fasteners per individual shingle. Where the roof slope exceeds 21 units vertical in 12 units horizontal (21:12, 175 percent slope), shingles shall be installed as required by the manufacturer.

905.2.7 Underlayment application. For roof slopes from two units vertical in 12 units horizontal (17-percent slope), up to four units vertical in 12 units horizontal (33-percent slope), underlayment shall be two layers applied in the following manner. Apply a 19-inch (483 mm) strip of underlayment felt parallel to and starting at the eaves, fastened sufficiently to hold in place. Starting at the eave, apply 36-inch-wide (914 mm) sheets of underlayment, overlapping successive sheets 19 inches (483 mm), and fastened sufficiently to hold in place. Distortions in the underlayment shall not interfere with the ability of the shingles to seal. For roof slopes of four units vertical in 12 units horizontal (33-percent slope) or greater, underlayment shall be one layer applied in the following manner. Underlayment shall be applied shingle fashion, parallel to and starting from the eave and lapped 2 inches (51 mm), fastened sufficiently to hold in place. Distortions in the underlayment shall not interfere with the ability of the shingles to seal. End laps shall be offset by 6 feet (1829 mm).

905.2.7.1 Ice barrier. In areas where there has been a history of ice forming along the eaves causing a backup of water as designated in Table 301.2(1), an ice barrier that consists of a least two layers of underlayment cemented together or of a self-adhering polymer modified bitumen sheet, shall be used in lieu of normal underlayment and extend from the lowest edges of all roof surfaces to a point at least 24 inches (610 mm) inside the exterior wall line of the building.

Exception: Detached accessory structures that contain no conditioned floor area.

905.2.7.2 Underlayment and high wind. Underlayment applied in areas subject to high winds [above 110 mph (49 m/s) per Figure 301.2(4) ] shall be applied with corrosion-resistant fasteners in accordance with manufacturer's installation instructions. Fasteners are to be applied along the overlap not farther apart than 36 inches (914 mm) on center.

905.2.8 Flashing. Flashing for asphalt shingles shall comply with this section.

905.2.8.1 Base and cap flashing. Base and cap flashing shall be installed in accordance with manufacturer's installation instructions. Base flashing shall be of either corrosion-resistant metal of minimum nominal 0.019 -inch ( 0.5 mm) thickness or mineral surface roll roofing weighing a minimum of 77 pounds per 100 square feet (4 kg/m2). Cap flashing shall be corrosion-resistant metal of minimum nominal 0.019 -inch ( 0.5 mm) thickness.

905.2.8.2 Valleys. Valley linings shall be installed in accordance with the manufacturer's installation instructions before applying shingles. Valley linings of the following types shall be permitted:

1. For open valleys (valley lining exposed) lined with metal, the valley lining shall be at least 24 inches (610 mm) wide and of any of the corrosion-resistant metals in Table 905.2.8.2.

2. For open valleys, valley lining of two plies of mineral surfaced roll roofing, complying with ASTM D 3909 or ASTM D 6380 Class M, shall be permitted. The bottom layer shall be 18 inches (457 mm) and the top layer a minimum of 36 inches (914 mm) wide.

3. For closed valleys (valley covered with shingles), valley lining of one ply of smooth roll roofing complying with ASTM D 6380 and at least 36 inches wide (914 mm) or valley lining as described in Item 1 or 2 above shall be permitted. Self-adhering polymer modified bitumen underlayment complying with ASTM D 1970 shall be permitted in lieu of the lining material.

TABLE 905.2.8.2

VALLEY LINING MATERIAL

MATERIAL MINIMUM THICKNESS (inches) GAGE WEIGHT (pounds)
Cold-rolled copper 0.0216 nominal - ASTM B 370, 16 oz. per square foot
Lead-coated copper 0.0216 nominal - ASTM B 101, 16 oz. per square foot
High-yield copper 0.0162 nominal - ASTM B 370, 12 oz. per square foot
Lead-coated high-yield copper 0.0162 nominal - ASTM B 101, 12 oz. per square foot
Aluminum 0.024 - -
Stainless steel - 28 -
Galvanized steel 0.0179 26 (zinc coated G90) -
Zinc alloy 0.027 - -
Lead - - 21/2
Painted terne - - 20

For SI: 1 inch = 25.4 mm, 1 pound = 0.454 kg.

905.2.8.3 Sidewall flashing. Flashing against a vertical sidewall shall be by the step-flashing method. The flashing shall be a minimum of 4 inches (102 mm) high and 4 inches (102 mm) wide. At the end of the vertical sidewall the step flashing shall be turned out in a manner that directs water away from the wall and onto the roof and/or gutter.

905.2.8.4 Other flashing. Flashing against a vertical front wall, as well as soil stack, vent pipe and chimney flashing, shall be applied according to the asphalt shingle manufacturer's printed instructions.

905.3 Clay and concrete tile. The installation of clay and concrete tile shall comply with the provisions of this section.

905.3.1 Deck requirements. Concrete and clay tile shall be installed only over solid sheathing or spaced structural sheathing boards.

905.3.2 Deck slope. Clay and concrete roof tile shall be installed on roof slopes of two and one-half units vertical in 12 units horizontal ( 21/2:12) or greater. For roof slopes from two and one-half units vertical in 12 units horizontal (21/2:12) to four units vertical in 12 units horizontal (4:12), double underlayment application is required in accordance with Section 905.3.3.

905.3.3 Underlayment. Unless otherwise noted, required underlayment shall conform to ASTM D 226 Type II; ASTM D 2626 Type I; or ASTM D 6380 Class M mineral surfaced roll roofing.

905.3.3.1 Low slope roofs. For roof slopes from two and one-half units vertical in 12 units horizontal (21/2:12), up to four units vertical in 12 units horizontal (4:12), underlayment shall be a minimum of two layers underlayment applied as follows:

1. Starting at the eave, a 19-inch (483 mm) strip of underlayment shall be applied parallel with the eave and fastened sufficiently in place.

2. Starting at the eave, 36-inch-wide (914 mm) strips of underlayment felt shall be applied, overlapping successive sheets 19 inches (483 mm), and fastened sufficiently in place.

905.3.3.2 High slope roofs. For roof slopes of four units vertical in 12 units horizontal (4:12) or greater, underlayment shall be a minimum of one layer of underlayment felt applied shingle fashion, parallel to and starting from the eaves and lapped 2 inches (51 mm), fastened sufficiently in place.

905.3.3.3 Underlayment and high wind. Underlayment applied in areas subject to high wind [over 110 miles per hour (49 m/s) per Figure 301.2(4) ] shall be applied with corrosion-resistant fasteners in accordance with manufacturer's installation instructions. Fasteners are to be applied along the overlap not farther apart than 36 inches (914 mm) on center.

905.3.4 Clay tile. Clay roof tile shall comply with ASTM C 1167.

905.3.5 Concrete tile. Concrete roof tile shall comply with ASTM C 1492.

905.3.6 Fasteners. Nails shall be corrosion resistant and not less than 11 gage, 5/16-inch (11 mm) head, and of sufficient length to penetrate the deck a minimum of 3/4 inch (19 mm) or through the thickness of the deck, whichever is less. Attaching wire for clay or concrete tile shall not be smaller than 0.083 inch (2 mm). Perimeter fastening areas include three tile courses but not less than 36 inches (914 mm) from either side of hips or ridges and edges of eaves and gable rakes.

905.3.7 Application. Tile shall be applied in accordance with this chapter and the manufacturer's installation instructions, based on the following:

1. Climatic conditions.

2. Roof slope.

3. Underlayment system.

4. Type of tile being installed.

Clay and concrete roof tiles shall be fastened in accordance with this section and the manufacturer's installation instructions. Perimeter tiles shall be fastened with a minimum of one fastener per tile. Tiles with installed weight less than 9 pounds per square foot ( 0.4 kg/m2) require a minimum of one fastener per tile regardless of roof slope. Clay and concrete roof tile attachment shall be in accordance with the manufacturer's installation instructions where applied in areas where the wind speed exceeds 100 miles per hour (45 m/s) and on buildings where the roof is located more than 40 feet (12 192 mm) above grade. In areas subject to snow, a minimum of two fasteners per tile is required. In all other areas, clay and concrete roof tiles shall be attached in accordance with Table 905.3.7.

TABLE 905.3.7

CLAY AND CONCRETE TILE ATTACHMENT

SHEATHING ROOF SLOPE NUMBER OF FASTENERS
Solid without battens All One per tile
Spaced or solid with battens and slope <= 5:12 Fasteners not required -
Spaced sheathing without battens 5:12 <= slope < 12:12 One per tile/every other row
   12:12 <= slope < 24:12 One per tile

905.3.8 Flashing. At the juncture of roof vertical surfaces, flashing and counterflashing shall be provided in accordance with this chapter and the manufacturer's installation instructions and, where of metal, shall not be less than 0.019 inch ( 0.5 mm) (No. 26 galvanized sheet gage) corrosion-resistant metal. The valley flashing shall extend at least 11 inches (279 mm) from the centerline each way and have a splash diverter rib not less than 1 inch (25 mm) high at the flow line formed as part of the flashing. Sections of flashing shall have an end lap of not less than 4 inches (102 mm). For roof slopes of three units vertical in 12 units horizontal (25-percent slope) and greater, valley flashing shall have a 36-inch-wide (914 mm) underlayment of one layer of Type I underlayment running the full length of the valley, in addition to other required underlayment. In areas where the average daily temperature in January is 25°F (-4°C) or less, metal valley flashing underlayment shall be solid-cemented to the roofing underlayment for slopes less than seven units vertical in 12 units horizontal (58-percent slope) or be of self-adhering polymer modified bitumen sheet.

905.4 Metal roof shingles. The installation of metal roof shingles shall comply with the provisions of this section.

905.4.1 Deck requirements. Metal roof shingles shall be applied to a solid or closely fitted deck, except where the roof covering is specifically designed to be applied to spaced sheathing.

905.4.2 Deck slope. Metal roof shingles shall not be installed on roof slopes below three units vertical in 12 units horizontal (25-percent slope).

905.4.3 Underlayment. Underlayment shall comply with ASTM D 226, Type I or Type II, ASTM D 4869, Type I or Type II, or ASTM D 1970. Underlayment shall be installed in accordance with the manufacturer's installation instructions.

905.4.3.1 Ice barrier. In areas where there has been a history of ice forming along the eaves causing a backup of water as designated in Table 301.2(1), an ice barrier that consists of at least two layers of underlayment cemented together or a self-adhering polymer modified bitumen sheet shall be used in place of normal underlayment and extend from the lowest edges of all roof surfaces to a point at least 24 inches (610 mm) inside the exterior wall line of the building.

Exception: Detached accessory structures that contain no conditioned floor area.

905.4.4 Material standards. Metal roof shingle roof coverings shall comply with Table 905.10.3(1). The materials used for metal roof shingle roof coverings shall be naturally corrosion resistant or be made corrosion resistant in accordance with the standards and minimum thicknesses listed in Table 905.10.3(2).

905.4.5 Application. Metal roof shingles shall be secured to the roof in accordance with this chapter and the approved manufacturer's installation instructions.

905.4.6 Flashing. Roof valley flashing shall be of corrosion-resistant metal of the same material as the roof covering or shall comply with the standards in Table 905.10.3(1). The valley flashing shall extend at least 8 inches (203 mm) from the center line each way and shall have a splash diverter rib not less than 3/4 inch (19 mm) high at the flow line formed as part of the flashing. Sections of flashing shall have an end lap of not less than 4 inches (102 mm). The metal valley flashing shall have a 36-inch-wide (914 mm) underlayment directly under it consisting of one layer of underlayment running the full length of the valley, in addition to underlayment required for metal roof shingles. In areas where the average daily temperature in January is 25°F (-4°C) or less, the metal valley flashing underlayment shall be solid cemented to the roofing underlayment for roof slopes under seven units vertical in 12 units horizontal (58-percent slope) or self-adhering polymer modified bitumen sheet.

905.5 Mineral-surfaced roll roofing. The installation of mineral-surfaced roll roofing shall comply with this section.

905.5.1 Deck requirements. Mineral-surfaced roll roofing shall be fastened to solidly sheathed roofs.

905.5.2 Deck slope. Mineral-surfaced roll roofing shall not be applied on roof slopes below one unit vertical in 12 units horizontal (8-percent slope).

905.5.3 Underlayment. Underlayment shall comply with ASTM D 226, Type I or ASTM D 4869, Type I or II.

905.5.3.1 Ice barrier. In areas where there has been a history of ice forming along the eaves causing a backup of water as designated in Table 301.2(1), an ice barrier that consists of at least two layers of underlayment cemented together or a self-adhering polymer modified bitumen sheet shall be used in place of normal underlayment and extend from the lowest edges of all roof surfaces to a point at least 24 inches (610 mm) inside the exterior wall line of the building.

Exception: Detached accessory structures that contain no conditioned floor area.

905.5.4 Material standards. Mineral-surfaced roll roofing shall conform to ASTM D 3909 or ASTM D 6380, Class M.

905.5.5 Application. Mineral-surfaced roll roofing shall be installed in accordance with this chapter and the manufacturer's installation instructions.

905.6 Slate and slate-type shingles. The installation of slate and slate-type shingles shall comply with the provisions of this section.

905.6.1 Deck requirements. Slate shingles shall be fastened to solidly sheathed roofs.

905.6.2 Deck slope. Slate shingles shall be used only on slopes of four units vertical in 12 units horizontal (33-percent slope) or greater.

905.6.3 Underlayment. Underlayment shall comply with ASTM D 226, Type I, or ASTM D 4869, Type I or II. Underlayment shall be installed in accordance with the manufacturer's installation instructions.

905.6.3.1 Ice barrier. In areas where there has been a history of ice forming along the eaves causing a backup of water as designated in Table 301.2(1), an ice barrier that consists of at least two layers of underlayment cemented together or a self-adhering polymer modified bitumen sheet shall be used in lieu of normal underlayment and extend from the lowest edges of all roof surfaces to a point at least 24 inches (610 mm) inside the exterior wall line of the building.

Exception: Detached accessory structures that contain no conditioned floor area.

905.6.4 Material standards. Slate shingles shall comply with ASTM C 406.

905.6.5 Application. Minimum headlap for slate shingles shall be in accordance with Table 905.6.5. Slate shingles shall be secured to the roof with two fasteners per slate. Slate shingles shall be installed in accordance with this chapter and the manufacturer's installation instructions.

TABLE 905.6.5

SLATE SHINGLE HEADLAP

SLOPE HEADLAP (inches)
4:12 <= slope < 8:12 4
8:12 <= slope < 20:12 3
Slope <= 20:12 2

For SI: 1 inch = 25.4 mm.

905.6.6 Flashing. Flashing and counterflashing shall be made with sheet metal. Valley flashing shall be a minimum of 15 inches (381 mm) wide. Valley and flashing metal shall be a minimum uncoated thickness of 0.0179 -inch ( 0.5 mm) zinc coated G90. Chimneys, stucco or brick walls shall have a minimum of two plies of felt for a cap flashing consisting of a 4-inch-wide (102 mm) strip of felt set in plastic cement and extending 1 inch (25 mm) above the first felt and a top coating of plastic cement. The felt shall extend over the base flashing 2 inches (51 mm).

905.7 Wood shingles. The installation of wood shingles shall comply with the provisions of this section.

905.7.1 Deck requirements. Wood shingles shall be installed on solid or spaced sheathing. Where spaced sheathing is used, sheathing boards shall not be less than 1-inch by 4-inch ( 25.4 mm by 102 mm) nominal dimensions and shall be spaced on centers equal to the weather exposure to coincide with the placement of fasteners.

905.7.1.1 Solid sheathing required. In areas where the average daily temperature in January is 25°F (-4°C) or less, solid sheathing is required on that portion of the roof requiring the application of an ice barrier.

905.7.2 Deck slope. Wood shingles shall be installed on slopes of three units vertical in 12 units horizontal (25-percent slope) or greater.

905.7.3 Underlayment. Underlayment shall comply with ASTM D 226, Type I or ASTM D 4869, Type I or II.

905.7.3.1 Ice barrier. In areas where there has been a history of ice forming along the eaves causing a backup of water as designated in Table 301.2(1), an ice barrier that consists of at least two layers of underlayment cemented together or a self-adhering polymer modified bitumen sheet shall be used in lieu of normal underlayment and extend from the lowest edges of all roof surfaces to a point at least 24 inches (610 mm) inside the exterior wall line of the building.

Exception: Detached accessory structures that contain no conditioned floor area.

905.7.4 Material standards. Wood shingles shall be of naturally durable wood and comply with the requirements of Table 905.7.4.

TABLE 905.7.4

WOOD SHINGLE MATERIAL REQUIREMENTS

MATERIAL MINIMUM GRADES APPLICABLE GRADING RULES
Wood shingles of naturally durable wood 1, 2 or 3 Cedar Shake and Shingle Bureau

905.7.5 Application. Wood shingles shall be installed according to this chapter and the manufacturer's installation instructions. Wood shingles shall be laid with a side lap not less than 11/2 inches (38 mm) between joints in courses, and no two joints in any three adjacent courses shall be in direct alignment. Spacing between shingles shall not be less than 1/4 inch to 3/8 inch (6 mm to 10 mm). Weather exposure for wood shingles shall not exceed those set in Table 905.7.5. Fasteners for wood shingles shall be corrosion resistant with a minimum penetration of 1/2 inch (13 mm) into the sheathing. For sheathing less than 1/2 inch (13 mm) in thickness, the fasteners shall extend through the sheathing. Wood shingles shall be attached to the roof with two fasteners per shingle, positioned no more than 3/4 inch (19 mm) from each edge and no more than 1 inch (25 mm) above the exposure line.

TABLE 905.7.5

WOOD SHINGLE WEATHER EXPOSURE AND ROOF SLOPE

ROOFING MATERIAL LENGTH (inches) GRADE EXPOSURE (inches)
3:12 pitch to < 4:12 pitch or 4:12 steeper
Shingles of naturally durable wood 16 No. 1 33/4 5
No. 2 31/2 4
No. 3 3 31/2
18 No. 1 41/4 51/2
No. 2 4 41/2
No. 3 31/2 4
24 No. 1 53/4 71/2
No. 2 51/2 61/2
No. 3 5 51/2

For SI: 1 inch = 25.4 mm.

905.7.6 Valley flashing. Roof flashing shall be not less than No. 26 gage [ 0.019 inches ( 0.5 mm)] corrosion-resistant sheet metal and shall extend 10 inches (254 mm) from the centerline each way for roofs having slopes less than 12 units vertical in 12 units horizontal (100-percent slope), and 7 inches (178 mm) from the centerline each way for slopes of 12 units vertical in 12 units horizontal and greater. Sections of flashing shall have an end lap of not less than 4 inches (102 mm).

905.7.7 Label required. Each bundle of shingles shall be identified by a label of an approved grading or inspection bureau or agency.

905.8 Wood shakes. The installation of wood shakes shall comply with the provisions of this section.

905.8.1 Deck requirements. Wood shakes shall be used only on solid or spaced sheathing. Where spaced sheathing is used, sheathing boards shall not be less than 1-inch by 4-inch (25 mm by 102 mm) nominal dimensions and shall be spaced on centers equal to the weather exposure to coincide with the placement of fasteners. Where 1-inch by 4-inch (25 mm by 102 mm) spaced sheathing is installed at 10 inches (254 mm) on center, additional 1-inch by 4-inch (25 mm by 102 mm) boards shall be installed between the sheathing boards.

905.8.1.1 Solid sheathing required. In areas where the average daily temperature in January is 25°F (-4°C) or less, solid sheathing is required on that portion of the roof requiring an ice barrier.

905.8.2 Deck slope. Wood shakes shall only be used on slopes of three units vertical in 12 units horizontal (25-percent slope) or greater.

905.8.3 Underlayment. Underlayment shall comply with ASTM D 226, Type I or ASTM D 4869, Type I or II.

905.8.3.1 Ice barrier. In areas where there has been a history of ice forming along the eaves causing a backup of water as designated in Table 301.2(1), an ice barrier that consists of at least two layers of underlayment cemented together or a self-adhering polymer modified bitumen sheet shall be used in place of normal underlayment and extend from the lowest edges of all roof surfaces to a point at least 24 inches (610 mm) inside the exterior wall line of the building.

Exception: Detached accessory structures that contain no conditioned floor area.

905.8.4 Interlayment. Interlayment shall comply with ASTM D 226, Type I.

905.8.5 Material standards. Wood shakes shall comply with the requirements of Table 905.8.5.

TABLE 905.8.5

WOOD SHAKE MATERIAL REQUIREMENTS

MATERIAL MINIMUM GRADES APPLICABLE GRADING RULES
Wood shakes of naturally durable wood 1 Cedar Shake and Shingle Bureau
Taper sawn shakes of naturally durable wood 1 or 2 Cedar Shake and Shingle Bureau
Preservative-treated shakes and shingles of naturally durable wood 1 Cedar Shake and Shingle Bureau
Fire-retardant-treated shakes and shingles of naturally durable wood 1 Cedar Shake and Shingle Bureau
Preservative-treated taper sawn shakes of Southern pine treated in accordance with AWPA Standard U1 (Commodity Specification A, Use Category 3B and Section 5.6 ) 1 or 2 Forest Products Laboratory of the Texas Forest Services

905.8.6 Application. Wood shakes shall be installed according to this chapter and the manufacturer's installation instructions. Wood shakes shall be laid with a side lap not less than 11/2 inches (38 mm) between joints in adjacent courses. Spacing between shakes in the same course shall be 3/8 inch to 5/8 inch ( 9.5 mm to 15.9 mm) for shakes and tapersawn shakes of naturally durable wood and shall be 3/8 inch to 5/8 inch ( 9.5 mm to 15.9 mm) for preservative-treated taper sawn shakes. Weather exposure for wood shakes shall not exceed those set forth in Table 905.8.6. Fasteners for wood shakes shall be corrosion-resistant, with a minimum penetration of 1/2 inch ( 12.7 mm) into the sheathing. For sheathing less than 1/2 inch ( 12.7 mm) thick, the fasteners shall extend through the sheathing. Wood shakes shall be attached to the roof with two fasteners per shake, positioned no more than 1 inch (25 mm) from each edge and no more than 2 inches (51 mm) above the exposure line.

905.8.7 Shake placement. The starter course at the eaves shall be doubled and the bottom layer shall be either 15-inch (381 mm), 18-inch (457 mm) or 24-inch (610 mm) wood shakes or wood shingles. Fifteen-inch (381 mm) or 18-inch (457 mm) wood shakes may be used for the final course at the ridge. Shakes shall be interlaid with 18-inch-wide (457 mm) strips of not less than No. 30 felt shingled between each course in such a manner that no felt is exposed to the weather by positioning the lower edge of each felt strip above the butt end of the shake it covers a distance equal to twice the weather exposure.

TABLE 905.8.6

WOOD SHAKE WEATHER EXPOSURE AND ROOF SLOPE

ROOFING MATERIAL LENGTH (inches) GRADE EXPOSURE (inches)
   4:12 pitch or steeper
Shakes of naturally durable wood 18 No. 1 71/2
   24 No. 1 10a
Preservative-treated taper sawn shakes of Southern Yellow Pine 18 No. 1 71/2
   24 No. 1 10
   18 No. 2 51/2
24 No. 2 71/2
Taper-sawn shakes of naturally durable wood 18 No. 1 71/2
   24 No. 1 10
   18 No. 2 51/2
24 No. 2 71/2

For SI: 1 inch = 25.4 mm.

a. For 24-inch by 3/8-inch handsplit shakes, the maximum exposure is 71/2 inches.

905.8.8 Valley flashing. Roof valley flashing shall not be less than No. 26 gage [ 0.019 inch ( 0.5 mm)] corrosion-resistant sheet metal and shall extend at least 11 inches (279 mm) from the centerline each way. Sections of flashing shall have an end lap of not less than 4 inches (102 mm).

905.8.9 Label required. Each bundle of shakes shall be identified by a label of an approved grading or inspection bureau or agency.

905.9 Built-up roofs. The installation of built-up roofs shall comply with the provisions of this section.

905.9.1 Slope. Built-up roofs shall have a design slope of a minimum of one-fourth unit vertical in 12 units horizontal (2-percent slope) for drainage, except for coal-tar built-up roofs, which shall have a design slope of a minimum one-eighth unit vertical in 12 units horizontal (1-percent slope).

905.9.2 Material standards. Built-up roof covering materials shall comply with the standards in Table 905.9.2.

905.9.3 Application. Built-up roofs shall be installed according to this chapter and the manufacturer's installation instructions.

TABLE 905.9.2

BUILT-UP ROOFING MATERIAL STANDARDS

MATERIAL STANDARD STANDARD
Acrylic coatings used in roofing ASTM D 6083
Aggregate surfacing ASTM D 1863
Asphalt adhesive used in roofing ASTM D 3747
Asphalt cements used in roofing ASTM D 3019; D 2822; D 4586
Asphalt-coated glass fiber base sheet ASTM D 4601
Asphalt coatings used in roofing ASTM D 1227; D 2823; D 2824; D 4479
Asphalt glass felt ASTM D 2178
Asphalt primer used in roofing ASTM D 41
Asphalt-saturated and asphalt-coated organic felt base sheet ASTM D 2626
Asphalt-saturated organic felt (perforated) ASTM D 226
Asphalt used in roofing ASTM D 312
Coal-tar cements used in roofing ASTM D 4022; D 5643
Coal-tar primer used in roofing, dampproofing and waterproofing ASTM D 43
Coal-tar saturated organic felt ASTM D 227
Coal-tar used in roofing ASTM D 450, Types I or II
Glass mat, coal tar ASTM D 4990
Glass mat, venting type ASTM D 4897
Mineral-surfaced inorganic cap sheet ASTM D 3909
Thermoplastic fabrics used in roofing ASTM D 5665; D 5726

905.10 Metal roof panels. The installation of metal roof panels shall comply with the provisions of this section.

905.10.1 Deck requirements. Metal roof panel roof coverings shall be applied to solid or spaced sheathing, except where the roof covering is specifically designed to be applied to spaced supports.

905.10.2 Slope. Minimum slopes for metal roof panels shall comply with the following:

1. The minimum slope for lapped, nonsoldered-seam metal roofs without applied lap sealant shall be three units vertical in 12 units horizontal (25-percent slope).

2. The minimum slope for lapped, nonsoldered-seam metal roofs with applied lap sealant shall be one-half vertical unit in 12 units horizontal (4-percent slope). Lap sealants shall be applied in accordance with the approved manufacturer's installation instructions.

3. The minimum slope for standing-seam roof systems shall be one-quarter unit vertical in 12 units horizontal (2-percent slope).

905.10.3 Material standards. Metal-sheet roof covering systems that incorporate supporting structural members shall be designed in accordance with the "Ohio Building Code". Metal-sheet roof coverings installed over structural decking shall comply with Table 905.10.3(1). The materials used for metal-sheet roof coverings shall be naturally corrosion resistant or provided with corrosion resistance in accordance with the standards and minimum thicknesses shown in Table 905.10.3(2).

905.10.4 Attachment. Metal roof panels shall be secured to the supports in accordance with this chapter and the manufacturer's installation instructions. In the absence of manufacturer's installation instructions, the following fasteners shall be used:

1. Galvanized fasteners shall be used for steel roofs.

2. Copper, brass, bronze, copper alloy and Three hundred series stainless steel fasteners shall be used for copper roofs.

3. Stainless steel fasteners are acceptable for metal roofs.

905.10.5 Underlayment. Underlayment shall be installed in accordance with the manufacturer's installation instructions.

TABLE 905.10.3(1)

METAL ROOF COVERINGS STANDARDS

ROOF COVERING TYPE STANDARD APPLICATION RATE/THICKNESS
Galvanized steel ASTM A 653 G90 Zinc coated
Stainless steel ASTM A 240, 300 Series alloys
Steel ASTM A 924
Lead-coated copper ASTM B 101
Cold rolled copper Hard lead ASTM B 370 minimum 16 oz/square ft and 12 oz/square ft high yield copper for metal-sheet roof-covering systems; 12 oz/square ft for preformed metal shingle systems.
2 lb/sq ft
Soft lead 3 lb/sq ft
Aluminum ASTM B 209, 0.024 minimum thickness for rollformed panels and 0.019 inch minimum thickness for pressformed shingles.
Terne (tin) and terne-coated stainless Terne coating of 40 lb per double base box, field painted where applicable in accordance with manufacturer's installation instructions.
Zinc 0.027 inch minimum thickness: 99.995 % electrolytic high grade zinc with alloy additives of copper ( 0.08 - 0.20 %), titanium ( 0.07 % - 0.12 %) and aluminum ( 0.015 %).

For SI: 1 ounce per square foot = 0.305 kg/m2, 1 pound per square foot = 4.214 kg/m2, 1 inch = 25.4 mm, 1 pound = 0.454 kg.

TABLE 905.10.3(2)

MINIMUM CORROSION RESISTANCE

55% aluminum-zinc alloy coated steel ASTM A 792 AZ 50
5% aluminum alloy-coated steel ASTM A 875 GF60
Aluminum-coated steel ASTM A 463 T2 65
Galvanized steel ASTM A 653 G-90
Prepainted steel ASTM A 755a

a. Paint systems in accordance with ASTM A 755 shall be applied over steel products with corrosion-resistant coatings complying with ASTM A 792, ASTM A 875, ASTM A 463, or ASTM A 653.

905.11 Modified bitumen roofing. The installation of modified bitumen roofing shall comply with the provisions of this section.

905.11.1 Slope. Modified bitumen membrane roofs shall have a design slope of a minimum of one-fourth unit vertical in 12 units horizontal (2-percent slope) for drainage.

905.11.2 Material standards. Modified bitumen roof coverings shall comply with the standards in Table 905.11.2.

TABLE 905.11.2

MODIFIED BITUMEN ROOFING MATERIAL STANDARDS

MATERIAL STANDARD
Acrylic coating ASTM D 6083
Asphalt adhesive ASTM D 3747
Asphalt cement ASTM D 3019
Asphalt coating ASTM D 1227; D 2824
Asphalt primer ASTM D 41
Modified bitumen roof membrane ASTM D 6162; D 6163; D 6164; D 6222; D 6223; D 6298; CGSB 37-GP-56M

905.11.3 Application. Modified bitumen roofs shall be installed according to this chapter and the manufacturer's installation instructions.

905.12 Thermoset single-ply roofing. The installation of thermoset single-ply roofing shall comply with the provisions of this section.

905.12.1 Slope. Thermoset single-ply membrane roofs shall have a design slope of a minimum of one-fourth unit vertical in 12 units horizontal (2-percent slope) for drainage.

905.12.2 Material standards. Thermoset single-ply roof coverings shall comply with ASTM D 4637, ASTM D 5019 or CGSB 37-GP-52M.

905.12.3 Application. Thermoset single-ply roofs shall be installed according to this chapter and the manufacturer's installation instructions.

905.13 Thermoplastic single-ply roofing. The installation of thermoplastic single-ply roofing shall comply with the provisions of this section.

905.13.1 Slope. Thermoplastic single-ply membrane roofs shall have a design slope of a minimum of one-fourth unit vertical in 12 units horizontal (2-percent slope).

905.13.2 Material standards. Thermoplastic single-ply roof coverings shall comply with ASTM D 4434, ASTM D 6754, ASTM D 6878, or CGSB CAN/CGSB 37.54.

905.13.3 Application. Thermoplastic single-ply roofs shall be installed according to this chapter and the manufacturer's installation instructions.

905.14 Sprayed polyurethane foam roofing. The installation of sprayed polyurethane foam roofing shall comply with the provisions of this section.

905.14.1 Slope. Sprayed polyurethane foam roofs shall have a design slope of a minimum of one-fourth unit vertical in 12 units horizontal (2-percent slope) for drainage.

905.14.2 Material standards. Spray-applied polyurethane foam insulation shall comply with ASTM C 1029, Type III or IV.

905.14.3 Application. Foamed-in-place roof insulation shall be installed in accordance with this chapter and the manufacturer's installation instructions. A liquid-applied protective coating that complies with Section 905.15 shall be applied no less than 2 hours nor more than 72 hours following the application of the foam.

905.14.4 Foam plastics. Foam plastic materials and installation shall comply with Section 316.

905.15 Liquid-applied coatings. The installation of liquid-applied coatings shall comply with the provisions of this section.

905.15.1 Slope. Liquid-applied roofs shall have a design slope of a minimum of one-fourth unit vertical in 12 units horizontal (2-percent slope).

905.15.2 Material standards. Liquid-applied roof coatings shall comply with ASTM C 836, C 957, D 1227, D 3468, D 6083, D 6694 or D 6947.

905.15.3 Application. Liquid-applied roof coatings shall be installed according to this chapter and the manufacturer's installation instructions.

SECTION 906

ROOF INSULATION

906.1 General. The use of above-deck thermal insulation shall be permitted provided such insulation is covered with an approved roof covering and passes FM 4450 or UL 1256.

906.2 Material standards. Above-deck thermal insulation board shall comply with the standards in Table 906.2.

TABLE 906.2

MATERIAL STANDARDS FOR ROOF INSULATION

Cellular glass board ASTM C 552
Composite boards ASTM C 1289, Type III, IV, V or VI
Expanded polystyrene ASTM C 578
Extruded polystyrene board ASTM C 578
Perlite board ASTM C 728
Polyisocyanurate board ASTM C 1289, Type I or Type II
Wood fiberboard ASTM C 208

SECTION 907

REROOFING

907.1 General. Materials and methods of application used for re-covering or replacing an existing roof covering shall comply with the requirements of Chapter 9.

Exception: Reroofing shall not be required to meet the minimum design slope requirement of one-quarter unit vertical in 12 units horizontal (2-percent slope) in Section 905 for roofs that provide positive roof drainage.

907.2 Structural and construction loads. The structural roof components shall be capable of supporting the roof covering system and the material and equipment loads that will be encountered during installation of the roof covering system.

907.3 Recovering versus replacement. New roof coverings shall not be installed without first removing all existing layers of roof coverings where any of the following conditions exist:

1. Where the existing roof or roof covering is water-soaked or has deteriorated to the point that the existing roof or roof covering is not adequate as a base for additional roofing.

2. Where the existing roof covering is wood shake, slate, clay, cement or asbestos-cement tile.

3. Where the existing roof has two or more applications of any type of roof covering.

4. For asphalt shingles, when the building is located in an area subject to moderate or severe hail exposure according to Figure 903.5.

Exceptions:

1. Complete and separate roofing systems, such as standing-seam metal roof systems, that are designed to transmit the roof loads directly to the building's structural system and that do not rely on existing roofs and roof coverings for support, shall not require the removal of existing roof coverings.

2. Installation of metal panel, metal shingle and concrete and clay tile roof coverings over existing wood shake roofs shall be permitted when the application is in accordance with Section 907.4.

3. The application of new protective coating over existing spray polyurethane foam roofing systems shall be permitted without tear-off of existing roof coverings.

907.4 Roof recovering. Where the application of a new roof covering over wood shingle or shake roofs creates a combustible concealed space, the entire existing surface shall be covered with gypsum board, mineral fiber, glass fiber or other approved materials securely fastened in place.

907.5 Reinstallation of materials. Existing slate, clay or cement tile shall be permitted for reinstallation, except that damaged, cracked or broken slate or tile shall not be reinstalled. Existing vent flashing, metal edgings, drain outlets, collars and metal counterflashings shall not be reinstalled where rusted, damaged or deteriorated. Aggregate surfacing materials shall not be reinstalled.

907.6 Flashings. Flashings shall be reconstructed in accordance with approved manufacturer's installation instructions. Metal flashing to which bituminous materials are to be adhered shall be primed prior to installation.

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

4101:8-9-01 [Effective 7/1/2019] Roof assemblies.

[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 901

GENERAL

901.1 Scope.The provisions of this chapter shall govern the design, materials, construction and quality of roof assemblies.

SECTION 902

FIRE CLASSIFICATION

902.1 Roofing covering materials.Roofs shall be covered with materials as set forth in Sections 904 and 905. Class A, B or C roofing shall be installed in jurisdictions designated by law as requiring their use or where the edge of the roof is less than 3 feet (914 mm) from a lot line. Class A, B and C roofing required by this section to be listed shall be tested in accordance with UL 790 or ASTM E108.

Exceptions:

1. Class A roof assemblies include those with coverings of brick, masonry and exposed concrete roof deck.

2. Class A roof assemblies include ferrous or copper shingles or sheets, metal sheets and shingles, clay or concrete roof tile, or slate installed on noncombustible decks.

3. Class A roof assemblies include minimum 16 ounces per square foot copper sheets installed over combustible decks.

4. Class A roof assemblies include slate installed over underlayment over combustible decks.

902.2 Fire-retardant-treated shingles and shakes.Fire-retardant-treated wood shakes and shingles shall be treated by impregnation with chemicals by the full-cell vacuum-pressure process, in accordance with AWPA C1. Each bundle shall be marked to identify the manufactured unit and the manufacturer, and shall be labeled to identify the classification of the material in accordance with the testing required in Section 902.1, the treating company and the quality control agency.

902.3 Building-integrated photovoltaic product.Building-integrated photovoltaic products installed as the roof covering shall be tested, listed and labeled for fire classification in accordance with Section 902.1.

902.4 Rooftop-mounted photovoltaic panel systems.Rooftop-mounted photovoltaic panel systems installed on or above the roof covering shall be tested, listed and identified with a fire classification in accordance with UL 1703 and UL 2703. Class A, B or C photovoltaic panel systems and modules shall be installed in jurisdictions designated by law as requiring their use or where the edge of the roof is less than 3 feet (914 mm) from a lot line.

SECTION 903

WEATHER PROTECTION

903.1 General.Roof decks shall be covered with approved roof coverings secured to the building or structure in accordance with the provisions of this chapter. Roof assemblies shall be designed and installed in accordance with this code and the approved manufacturer's instructions such that the roof assembly shall serve to protect the building or structure.

903.2 Flashing.Flashings shall be installed in a manner that prevents moisture from entering the wall and roof through joints in copings, through moisture permeable materials and at intersections with parapet walls and other penetrations through the roof plane.

903.2.1 Locations.Flashings shall be installed at wall and roof intersections, wherever there is a change in roof slope or direction and around roof openings. A flashing shall be installed to divert the water away from where the eave of a sloped roof intersects a vertical sidewall. Where flashing is of metal, the metal shall be corrosion resistant with a thickness of not less than 0.019 inch ( 0.5 mm) (No. 26 galvanized sheet).

903.2.2 Crickets and saddles.A cricket or saddle shall be installed on the ridge side of any chimney or penetration more than 30 inches (762 mm) wide as measured perpendicular to the slope. Cricket or saddle coverings shall be sheet metal or of the same material as the roof covering.

Exception:Unit skylights installed in accordance with Section R 308.6 and flashed in accordance with the manufacturer's instructions shall be permitted to be installed without a cricket or saddle.

903.3 Coping.Parapet walls shall be properly coped with noncombustible, weatherproof materials of a width not less than the thickness of the parapet wall.

903.4 Roof drainage.Unless roofs are sloped to drain over roof edges, roof drains shall be installed at each low point of the roof.

903.4.1 Secondary (emergency overflow) drains or scuppers. Where roof drains are required, secondary emergency overflow roof drains or scuppers shall be provided where the roof perimeter construction extends above the roof in such a manner that water will be entrapped if the primary drains allow buildup for any reason. Overflow drains having the same size as the roof drains shall be installed with the inlet flow line located 2 inches (51 mm) above the low point of the roof, or overflow scuppers having three times the size of the roof drains and having a minimum opening height of 4 inches (102 mm) shall be installed in the adjacent parapet walls with the inlet flow located 2 inches (51 mm) above the low point of the roof served. The installation and sizing of overflow drains, leaders and conductors shall comply with Sections 1106 and 1108 of the plumbing code, as applicable. Overflow drains shall discharge to an approved location and shall not be connected to roof drain lines.

SECTION 904

MATERIALS

904.1 Scope. The requirements set forth in this section shall apply to the application of roof covering materials specified herein. Roof assemblies shall be applied in accordance with this chapter and the manufacturer's installation instructions. Installation of roof assemblies shall comply with the applicable provisions of Section 905.

904.2 Compatibility of materials.Roof assemblies shall be of materials that are compatible with each other and with the building or structure to which the materials are applied.

904.3 Material specifications and physical characteristics.Roof covering materials shall conform to the applicable standards listed in this chapter.

904.4 Product identification.Roof covering materials shall be delivered in packages bearing the manufacturer's identifying marks and approved testing agency labels required. Bulk shipments of materials shall be accompanied by the same information issued in the form of a certificate or on a bill of lading by the manufacturer.

SECTION 905

REQUIREMENTS FOR ROOF COVERINGS

905.1 Roof covering application.Roof coverings shall be applied in accordance with the applicable provisions of this section and the manufacturer's installation instructions. Unless otherwise specified in this section, roof coverings shall be installed to resist the component and cladding loads specified in Table 301.2(2), adjusted for height and exposure in accordance with Table 301.2(3).

905.1.1 Underlayment.Underlayment for asphalt shingles, clay and concrete tile, metal roof shingles, mineral-surfaced roll roofing, slate and slate-type shingles, wood shingles, wood shakes, metal roof panels and photovoltaic shingles shall conform to the applicable standards listed in this chapter. Underlayment materials required to comply with ASTM D226, D1970, D4869 and D6757 shall bear a label indicating compliance to the standard designation and, if applicable, type classification indicated in Table 905.1.1(1). Underlayment shall be applied in accordance with Table 905.1.1(2). Underlayment shall be attached in accordance with Table 905.1.1(3).

Exceptions:

1. As an alternative, self-adhering polymer-modified bitumen underlayment complying with ASTM D1970 installed in accordance with both the underlayment manufacturer's and roof covering manufacturer's instructions for the deck material, roof ventilation configuration and climate exposure for the roof covering to be installed, shall be permitted.

2. As an alternative, a minimum 4-inch-wide (102 mm) strip of self-adhering polymer-modified bitumen membrane complying with ASTM D1970, installed in accordance with the manufacturer's installation instructions for the deck material, shall be applied over all joints in the roof decking. An approved underlayment for the applicable roof covering for maximum ultimate design wind speeds, Vult, less than 140 miles per hour shall be applied over the entire roof over the 4-inch-wide (102 mm) membrane strips.

3. As an alternative, two layers of underlayment complying with ASTM D226 Type II or ASTM D4869 Type III or Type IV shall be permitted to be installed as follows in 3.1 - 3.4:

3.1. Apply a 19-inch-wide (483 mm) strip of underlayment parallel with the eave. Starting at the eave, apply 36-inch-wide (914 mm) strips of underlayment felt, overlapping successive sheets 19 inches (483 mm). End laps shall be 4 inches (102 mm) and shall be offset by 6 feet (1829 mm).

3.2. The underlayment shall be attached with corrosion-resistant fasteners in a grid pattern of 12 inches (305 mm) between side laps with a 6-inch (152 mm) spacing at side and end laps.

3.3. Underlayment shall be attached using metal or plastic cap nails with a nominal cap diameter of not less than 1 inch (25 mm). Metal caps shall have a thickness of not less than 32-gage sheet metal. Power-driven metal caps shall have a thickness of not less than 0.010 inch ( 0.25 mm). Minimum thickness of the outside edge of plastic caps shall be 0.035 inch ( 0.89 mm).

3.4. The cap nail shank shall be not less than 0.083 inch ( 2.11 mm) for ring shank cap nails and 0.091 inch ( 2.31 mm) for smooth shank cap nails. Cap nail shank shall have a length sufficient to penetrate through the roof sheathing or not less than3/4 inch (19 mm) into the roof sheathing.

TABLE 905.1.1(1)

UNDERLAYMENT TYPES

ROOF COVERING

SECTION

MAXIMUM ULTIMATE DESIGN WIND SPEED, Vult < 140 MPH

MAXIMUM ULTIMATE DESIGN WIND SPEED, Vult >=140 MPH

Asphalt shingles

905.2

ASTM D226 Type I

ASTM D4869 Type I, II, III or IV

ASTM D6757

ASTM D226 Type II

ASTM D4869 Type III or Type IV

ASTM D6757

Clay and concrete tile

905.3

ASTM D226 Type II

ASTM D2626 Type I

ASTM D6380 Class M mineral-surfaced roll roofing

ASTM D226 Type II

ASTM D2626 Type I

ASTM D6380 Class M mineral-surfaced roll roofing

Metal roof shingles

905.4

ASTM D226 Type I or II

ASTM D4869 Type I, II, III or IV

ASTM D226 Type II

ASTM D4869 Type III or Type IV

Mineral-surfaced roll roofing

905.5

ASTM D226 Type I or II

ASTM D4869 Type I, II, III or IV

ASTM D226 Type II

ASTM D4869 Type III or Type IV

Slate and slate-type shingles

905.6

ASTM D226 Type I

ASTM D4869 Type I, II, III or IV

ASTM D226 Type II

ASTM D4869 Type III or Type IV

Wood shingles

905.7

ASTM D226 Type I or II

ASTM D4869 Type I, II, III or IV

ASTM D226 Type II

ASTM D4869 Type III or Type IV

Wood shakes

905.8

ASTM D226 Type I or II

ASTM D4869 Type I, II, III or IV

ASTM D226 Type II

ASTM D4869 Type III or Type IV

Metal panels

905.10

Manufacturer's instructions

ASTM D226 Type II

ASTM D4869 Type III or Type IV

Photovoltaic shingles

905.16

ASTM D4869 Type I, II, III or IV

ASTM D6757

ASTM D4869 Type III or Type IV

ASTM D6757

For SI: 1 mile per hour = 0.447 m/s.

TABLE R05.1.1(2)

UNDERLAYMENT APPLICATION

ROOF COVERING

SECTION

MAXIMUM ULTIMATE DESIGN WIND SPEED, Vult < 140 MPH

MAXIMUM ULTIMATE DESIGN WIND SPEED, Vult >=140 MPH

Asphalt shingles

905.2

For roof slopes from two units vertical in 12 units horizontal (2:12), up to four units vertical in 12 units horizontal (4:12), underlayment shall be two layers applied in the following manner: apply a 19-inch strip of underlayment felt parallel to and starting at the eaves. Starting at the eave, apply 36-inch-wide sheets of underlayment, overlapping successive sheets 19 inches. Distortions in the underlayment shall not interfere with the ability of the shingles to seal. End laps shall be 4 inches and shall be offset by 6 feet. For roof slopes of four units vertical in 12 units horizontal (4:12) or greater, underlayment shall be one layer applied in the following manner: underlayment shall be applied shingle fashion, parallel to and starting from the eave and lapped 2 inches, Distortions in the underlayment shall not interfere with the ability of the shingles to seal. End laps shall be 4 inches and shall be offset by 6 feet.

Same as Maximum Ultimate Design Wind Speed, Vult < 140 mph except all laps shall be not less than 4 inches.

Clay and concrete tile

905.3

For roof slopes from two and one-half units vertical in 12 units horizontal (21/2 :12), up to four units vertical in 12 units horizontal (4:12), underlayment shall be not fewer than two layers applied as follows: starting at the eave, apply a 19-inch strip of underlayment parallel with the eave. Starting at the eave, apply 36-inch-wide strips of underlayment felt, overlapping successive sheets 19 inches. End laps shall be 4 inches and shall be off-set by 6 feet. For roof slopes of four units vertical in 12 units horizontal (4:12) or greater, underlayment shall be not fewer than one layer of underlayment felt applied shingle fashion, parallel to and starting from the eaves and lapped 2 inches. End laps shall be 4 inches and shall be offset by 6 feet.

Same as Maximum Ultimate Design Wind Speed, Vult < 140 mph, except all laps shall be not less than 4 inches.

Metal roof shingles

905.4

Apply in accordance with the manufacturer's installation instructions.

For roof slopes from two units vertical in 12 units horizontal (2:12), up to four units vertical in 12 units horizontal (4:12), underlayment shall be two layers applied in the following manner: apply a 19-inch strip of underlayment felt parallel to and starting at the eaves. Starting at the eave, apply 36-inch-wide sheets of underlayment, overlapping successive sheets 19 inches. End laps shall be 4 inches and shall be offset by 6 feet. For roof slopes of four units vertical in 12 units horizontal (4:12) or greater, underlayment shall be one layer applied in the following manner: under- layment shall be applied shingle fashion, parallel to and starting from the eave and lapped 4 inches. End laps shall be 4 inches and shall be offset by 6 feet.

Mineral-surfaced roll roofing

905.5

Slate and slate-type shingles

905.6

Wood shingles

905.7

Wood shakes

905.8

Metal panels

905.10

Photovoltaic shingles

905.16

For roof slopes from two units vertical in 12 units horizontal (2:12), up to four units vertical in 12 units horizontal (4:12), underlayment shall be two layers applied in the following manner: apply a 19- inch strip of underlayment felt parallel to and starting at the eaves. Starting at the eave, apply 36-inch- wide sheets of underlayment, overlapping successive sheets 19 inches. Distortions in the underlayment shall not interfere with the ability of the shingles to seal. End laps shall be 4 inches and shall be offset by 6 feet. For roof slopes of four units vertical in 12 units horizontal (4:12) or greater, underlayment shall be one layer applied in the following manner: underlayment shall be applied shingle fashion, parallel to and starting from the eave and lapped 2 inches. Distortions in the underlayment shall not interfere with the ability of the shingles to seal. End laps shall be 4 inches and shall be offset by 6 feet.

Same as Maximum Ultimate Design Wind Speed, Vult < 140 mph, except all laps shall be not less than 4 inches.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s.

TABLE 905.1.1(3)

UNDERLAYMENT ATTACHMENT

ROOF COVERING

SECTION

MAXIMUM ULTIMATE DESIGN WIND SPEED,Vult < 140 MPH

MAXIMUM ULTIMATE DESIGN WIND SPEED, Vult > 140 MPH

Asphalt shingles

905.2

Fastened sufficiently to hold in place

The underlayment shall be attached with corrosion-resistant fasteners in a grid pattern of 12 inches between side laps with a 6-inch spacing at side and end laps.

Underlayment shall be attached using metal or plastic cap nails or cap staples with a nominal cap diameter of not less than 1 inch. Metal caps shall have a thickness of not less than 32-gage sheet metal. Power-driven metal caps shall have a minimum thickness of 0.010 inch. Minimum thickness of the outside edge of plastic caps shall be 0.035 inch. The cap nail shank shall be not less than 0.083 inch for ring shank cap nails and 0.091 inch for smooth shank cap nails. Staples shall be not less than 21 gage. Cap nail shank and cap staple legs shall have a length sufficient to penetrate through the roof sheathing or not less than3/ inch into the roof sheathing.

Clay and concrete tile

905.3

Photovoltaic

905.16

Metal roof shingles

905.4

Manufacturer's installation instructions.

The underlayment shall be attached with corrosion-resistant fasteners in a grid pattern of 12 inches between side laps with a 6-inch spacing at side and end laps.

Underlayment shall be attached using metal or plastic cap nails or cap staples with a nominal cap diameter of not less than 1 inch. Metal caps shall have a thickness of not less than 32-gage sheet metal. Power-driven metal caps shall have a minimum thickness of 0.010 inch. Minimum thickness of the outside edge of plastic caps shall be 0.035 inch. The cap nail shank shall be not less than 0.083 inch for ring shank cap nails and 0.091 inch for smooth shank cap nails. Staples shall be not less than 21 gage. Cap nail shank and cap staple legs shall have a length sufficient to penetrate through the roof sheathing or not less than3/ inch into the roof sheathing.

Mineral-surfaced roll roofing

905.5

Slate and slate-type shingles

905.6

Wood shingles

905.7

Wood shakes

905.8

Metal panels

905.10

For SI: 1 inch = 25.4 mm, 1 mile per hour = 0.447 m/s.

905.1.2 Ice barriers.In areas where there has been a history of ice forming along the eaves causing a backup of water as designated in Table 301.2(1), an ice barrier shall be installed for asphalt shingles, metal roof shingles, mineral-surfaced roll roofing, slate and slate-type shingles, wood shingles and wood shakes. The ice barrier shall consist of not fewer than two layers of underlayment cemented together, or a self-adhering polymer-modified bitumen sheet shall be used in place of normal underlayment and extend from the lowest edges of all roof surfaces to a point not less than 24 inches (610 mm) inside the exterior wall line of the building. The 24 inch measurement shall be along the slope of the roof from the point where the projected outside face of the wall intersects the roof deck. On roofs with slope equal to or greater than eight units vertical in 12 units horizontal (67-percent slope), the ice barrier shall also be applied not less than 36 inches (914 mm) measured along the roof slope from the eave edge of the building.

Exception:Detached accessory structures and roof assemblies terminating at a vertical wall over unconditioned floor areas.

905.2 Asphalt shingles.The installation of asphalt shingles shall comply with the provisions of this section.

905.2.1 Sheathing requirements.Asphalt shingles shall be fastened to solidly sheathed decks.

905.2.2 Slope.Asphalt shingles shall be used only on roof slopes of two units vertical in 12 units horizontal (17-percent slope) or greater. For roof slopes from two units vertical in 12 units horizontal (17-percent slope) up to four units vertical in 12 units horizontal (33-percent slope), double underlayment application is required in accordance with Section 905.1.1.

905.2.3 Underlayment.Underlayment shall comply with Section 905.1.1.

905.2.4 Asphalt shingles.Asphalt shingles shall comply with ASTM D3462.

905.2.4.1 Wind resistance of asphalt shingles.Asphalt shingles shall be tested in accordance with ASTM D7158. Asphalt shingles shall meet the classification requirements of Table 905.2.4.1 for the appropriate ultimate design wind speed. Asphalt shingle packaging shall bear a label to indicate compliance with ASTM D7158 and the required classification in Table 905.2.4.1.

Exception: Asphalt shingles not included in the scope of ASTM D7158 shall be tested and labeled in accordance with ASTM D3161. Asphalt shingle packaging shall bear a label to indicate compliance with ASTM D3161 and the required classification in Table 905.2.4.1.

TABLE 905.2.4.1

CLASSIFICATION OF ASPHALT ROOF SHINGLES

MAXIMUM ULTIMATE DESIGN WIND SPEED, Vult FROM FIGURE 301.2(5) A (mph)

MAXIMUM BASIC WIND SPEED, Vasd FROM TABLE 301.2.1.3 (mph)

ASTM D7158a SHINGLE CLASSIFICATION

ASTM D3161 SHINGLE CLASSIFICATION

110

85

D, G or H

A, D or F

116

90

D, G or H

A, D or F

129

100

G or H

A, D or F

142

110

G or H

F

155

120

G or H

F

168

130

H

F

181

140

H

F

194

150

H

F

For SI: 1 foot = 304.8 mm; 1 mile per hour = 0.447 m/s.

a. The standard calculations contained in ASTM D7158 assume Exposure Category B or C and a building height of 60 feet or less. Additional calculations are required for conditions outside of these assumptions.

905.2.5 Fasteners.Fasteners for asphalt shingles shall be galvanized steel, stainless steel, aluminum or copper roofing nails, minimum 12-gage [ 0.105 inch (3 mm)] shank with a minimum3/8-inch-diameter ( 9.5 mm) head, complying with ASTM F1667, of a length to penetrate through the roofing materials and not less than3/4 inch ( 19.1 mm) into the roof sheathing. Where the roof sheathing is less than3/4 inch ( 19.1 mm) thick, the fasteners shall penetrate through the sheathing.

905.2.6 Attachment.Asphalt shingles shall have the minimum number of fasteners required by the manufacturer's approved installation instructions, but not less than four fasteners per strip shingle or two fasteners per individual shingle. Where the roof slope exceeds 21 units vertical in 12 units horizontal (21:12, 175-percent slope), shingles shall be installed in accordance with the manufacturer's approved installation instructions.

905.2.7 Ice barrier.Where required, ice barriers shall comply with Section 905.1.2.

905.2.8 Flashing.Flashing for asphalt shingles shall comply with this section and the asphalt shingle manufacturer's approved installation instructions.

905.2.8.1 Base and cap flashing.Base and cap flashing shall be installed in accordance with manufacturer's instructions. Base flashing shall be of either corrosion-resistant metal of minimum nominal 0.019 -inch ( 0.5 mm) thickness or mineral-surfaced roll roofing weighing not less than 77 pounds per 100 square feet (4 kg/m2). Cap flashing shall be corrosion-resistant metal of minimum nominal 0.019 -inch ( 0.5 mm) thickness.

905.2.8.2 Valleys.Valley linings shall be installed in accordance with the manufacturer's instructions before applying shingles. Valley linings of the following types shall be permitted:

1. For open valleys (valley lining exposed) lined with metal, the valley lining shall be not less than 24 inches (610 mm) wide and of any of the corrosion-resistant metals in Table 905.2.8.2.

2. For open valleys, valley lining of two plies of mineral-surfaced roll roofing, complying with ASTM D3909 or ASTM D6380 Class M, shall be permitted. The bottom layer shall be 18 inches (457 mm) and the top layer not less than 36 inches (914 mm) wide.

3. For closed valleys (valley covered with shingles), valley lining of one ply of smooth roll roofing complying with ASTM D6380 and not less than 36 inches wide (914 mm) or valley lining as described in Item 1 or 2 shall be permitted. Self-adhering polymer-modified bitumen underlayment complying with ASTM D1970 shall be permitted in lieu of the lining material.

TABLE 905.2.8.2

VALLEY LINING MATERIAL

MATERIAL

MINIMUM THICKNESS (inches)

GAGE

WEIGHT (pounds)

Cold-rolled copper

0.0216 nominal

-

ASTM B370, 16 oz. per square foot

Lead-coated copper

0.0216 nominal

-

ASTM B101, 16 oz. per square foot

High-yield copper

0.0162 nominal

-

ASTM B370, 12 oz. per square foot

Lead-coated high-yield copper

0.0162 nominal

-

ASTM B101, 12 oz. per square foot

Aluminum

0.024

-

-

Stainless steel

-

28

-

Galvanized steel

0.0179

26 (zinc coated G90)

-

Zinc alloy

0.027

-

-

Lead

-

-

21/2

Painted terne

-

-

20

For SI: 1 inch = 25.4 mm, 1 pound = 0.454 kg.

905.2.8.3 Sidewall flashing.Base flashing against a vertical sidewall shall be continuous or step flashing and shall be not less than 4 inches (102 mm) in height and 4 inches (102 mm) in width and shall direct water away from the vertical sidewall onto the roof or into the gutter. Where siding is provided on the vertical sidewall, the vertical leg of the flashing shall be continuous under the siding. Where anchored masonry veneer is provided on the vertical sidewall, the base flashing shall be provided in accordance with this section and counterflashing shall be provided in accordance with Section 703.8.2.2. Where exterior plaster or adhered masonry veneer is provided on the vertical sidewall, the base flashing shall be provided in accordance with this section and Section 703.6.3.

905.2.8.4 Other flashing.Flashing against a vertical front wall, as well as soil stack, vent pipe and chimney flashing, shall be applied in accordance with the asphalt shingle manufacturer's printed instructions.

905.2.8.5 Drip edge.Refer to Sections 903.1 and 905.1.

905.3 Clay and concrete tile.The installation of clay and concrete tile shall comply with the provisions of this section.

905.3.1 Deck requirements.Concrete and clay tile shall be installed only over solid sheathing or spaced structural sheathing boards.

905.3.2 Deck slope.Clay and concrete roof tile shall be installed on roof slopes of two and one-half units vertical in 12 units horizontal (25-percent slope) or greater. For roof slopes from two and one-half units vertical in 12 units horizontal (25-percent slope) to four units vertical in 12 units horizontal (33-percent slope), double underlayment application is required in accordance with Section 905.3.3.

905.3.3 Underlayment.Underlayment shall comply with Section 905.1.1.

905.3.4 Clay tile.Clay roof tile shall comply with ASTM C1167.

905.3.5 Concrete tile.Concrete roof tile shall comply with ASTM C1492.

905.3.6 Fasteners.Nails shall be corrosion resistant and not less than 11-gage, 5/16-inch (11 mm) head, and of sufficient length to penetrate the deck not less than3/4 inch (19 mm) or through the thickness of the deck, whichever is less. Attaching wire for clay or concrete tile shall not be smaller than 0.083 inch (2 mm). Perimeter fastening areas include three tile courses but not less than 36 inches (914 mm) from either side of hips or ridges and edges of eaves and gable rakes.

905.3.7 Application.Tile shall be applied in accordance with this chapter and the manufacturer's installation instructions, based on the following:

1. Climatic conditions.

2. Roof slope.

3. Underlayment system.

4. Type of tile being installed.

Clay and concrete roof tiles shall be fastened in accordance with this section and the manufacturer's installation instructions. Perimeter tiles shall be fastened with not less than one fastener per tile. Tiles with installed weight less than 9 pounds per square foot ( 0.4 kg/m2) require not less than one fastener per tile regardless of roof slope. Clay and concrete roof tile attachment shall be in accordance with the manufacturer's installation instructions where applied in areas where the ultimate design wind speed exceeds 130 miles per hour (58 m/s) and on buildings where the roof is located more than 40 feet (12 192 mm) above grade. In areas subject to snow, not less than two fasteners per tile are required. In other areas, clay and concrete roof tiles shall be attached in accordance with Table 905.3.7.

TABLE 905.3.7

CLAY AND CONCRETE TILE ATTACHMENT

SHEATHING

ROOF SLOPE

NUMBER OF FASTENERS

Solid without battens

All

One per tile

Spaced or solid with battens and slope < 5:12

Fasteners not required

-

Spaced sheathing without battens

5:12 < slope < 12:12

One per tile/ every other row

  

12:12 < slope < 24:12

One per tile

905.3.8 Flashing.At the juncture of roof vertical surfaces, flashing and counterflashing shall be provided in accordance with this chapter and the manufacturer's installation instructions and, where of metal, shall be not less than 0.019 inch ( 0.5 mm) (No. 26 galvanized sheet gage) corrosion-resistant metal. The valley flashing shall extend not less than 11 inches (279 mm) from the centerline each way and have a splash diverter rib not less than 1 inch (25 mm) in height at the flow line formed as part of the flashing. Sections of flashing shall have an end lap of not less than 4 inches (102 mm). For roof slopes of three units vertical in 12 units horizontal (25-percent slope) and greater, valley flashing shall have a 36-inch-wide (914 mm) underlayment of one layer of Type I underlayment running the full length of the valley, in addition to other required underlayment. In areas where the average daily temperature in January is 25°F (-4°C) or less, metal valley flashing underlayment shall be solid-cemented to the roofing underlayment for slopes less than seven units vertical in 12 units horizontal (58-percent slope) or be of self-adhering polymer-modified bitumen sheet.

905.4 Metal roof shingles.The installation of metal roof shingles shall comply with the provisions of this section.

905.4.1 Deck requirements.Metal roof shingles shall be applied to a solid or closely fitted deck, except where the roof covering is specifically designed to be applied to spaced sheathing.

905.4.2 Deck slope.Metal roof shingles shall not be installed on roof slopes below three units vertical in 12 units horizontal (25-percent slope).

905.4.3 Underlayment.Underlayment shall comply with Section 905.1.1.

905.4.3.1 Ice barrier.Where required, ice barriers shall comply with Section 905.1.2.

905.4.4 Material standards.Metal roof shingle roof coverings shall comply with Table 905.10.3(1). The materials used for metal roof shingle roof coverings shall be naturally corrosion resistant or be made corrosion resistant in accordance with the standards and minimum thicknesses listed in Table 905.10.3(2).

905.4.5 Application.Metal roof shingles shall be secured to the roof in accordance with this chapter and the approved manufacturer's installation instructions.

905.4.6 Flashing.Roof valley flashing shall be of corrosion-resistant metal of the same material as the roof covering or shall comply with the standards in Table 905.10.3(1). The valley flashing shall extend not less than 8 inches (203 mm) from the centerline each way and shall have a splash diverter rib not less than3/4 inch (19 mm) in height at the flow line formed as part of the flashing. Sections of flashing shall have an end lap of not less than 4 inches (102 mm). The metal valley flashing shall have a 36-inch-wide (914 mm) underlayment directly under it consisting of one layer of underlayment running the full length of the valley, in addition to underlayment required for metal roof shingles. In areas where the average daily temperature in January is 25°F (-4°C) or less, the metal valley flashing underlayment shall be solid-cemented to the roofing underlayment for roof slopes under seven units vertical in 12 units horizontal (58-percent slope) or self-adhering polymer-modified bitumen sheet.

905.5 Mineral-surfaced roll roofing.The installation of mineral-surfaced roll roofing shall comply with this section.

905.5.1 Deck requirements.Mineral-surfaced roll roofing shall be fastened to solidly sheathed roofs.

905.5.2 Deck slope.Mineral-surfaced roll roofing shall not be applied on roof slopes below one unit vertical in 12 units horizontal (8-percent slope).

905.5.3 Underlayment.Underlayment shall comply with Section 905.1.1.

905.5.3.1 Ice barrier.Where required, ice barriers shall comply with Section 905.1.2.

905.5.4 Material standards.Mineral-surfaced roll roofing shall conform to ASTM D3909 or ASTM D6380, Class M.

905.5.5 Application.Mineral-surfaced roll roofing shall be installed in accordance with this chapter and the manufacturer's instructions.

905.6 Slate shingles.The installation of slate shingles shall comply with the provisions of this section.

905.6.1 Deck requirements.Slate shingles shall be fastened to solidly sheathed roofs.

905.6.2 Deck slope.Slate shingles shall be used only on slopes of four units vertical in 12 units horizontal (33-percent slope) or greater.

905.6.3 Underlayment.Underlayment shall comply with Section 905.1.1.

905.6.3.1 Ice barrier.Where required, ice barriers shall comply with Section 905.1.2.

905.6.4 Material standards.Slate shingles shall comply with ASTM C406.

905.6.5 Application.Minimum headlap for slate shingles shall be in accordance with Table 905.6.5. Slate shingles shall be secured to the roof with two fasteners per slate. Slate shingles shall be installed in accordance with this chapter and the manufacturer's instructions.

TABLE 905.6.5

SLATE SHINGLE HEADLAP

SLOPE

HEADLAP (inches)

4:12 <= slope < 8:12

4

8:12 <= slope < 20:12

3

Slope >= 20:12

2

For SI: 1 inch = 25.4 mm.

905.6.6 Flashing.Flashing and counterflashing shall be made with sheet metal. Valley flashing shall be not less than 15 inches (381 mm) wide. Valley and flashing metal shall be a minimum uncoated thickness of 0.0179 -inch ( 0.5 mm) zinc coated G90. Chimneys, stucco or brick walls shall have not less than two plies of felt for a cap flashing consisting of a 4-inch-wide (102 mm) strip of felt set in plastic cement and extending 1 inch (25 mm) above the first felt and a top coating of plastic cement. The felt shall extend 2 inches (51 mm) over the base flashing.

905.7 Wood shingles.The installation of wood shingles shall comply with the provisions of this section.

905.7.1 Deck requirements.Wood shingles shall be installed on solid or spaced sheathing. Where spaced sheathing is used, sheathing boards shall be not less than 1-inch by 4-inch (25 mm by 102 mm) nominal dimensions and shall be spaced on centers equal to the weather exposure to coincide with the placement of fasteners.

905.7.1.1 Solid sheathing required.In areas where the average daily temperature in January is 25°F (-4°C) or less, solid sheathing is required on that portion of the roof requiring the application of an ice barrier.

905.7.2 Deck slope.Wood shingles shall be installed on slopes of three units vertical in 12 units horizontal (25-percent slope) or greater.

905.7.3 Underlayment.Underlayment shall comply with Section 905.1.1.

905.7.3.1 Ice barrier.Where required, ice barriers shall comply with Section 905.1.2.

905.7.4 Material standards.Wood shingles shall be of naturally durable wood and comply with the requirements of Table 905.7.4.

TABLE 905.7.4

WOOD SHINGLE MATERIAL REQUIREMENTS

MATERIAL

MINIMUM GRADES

APPLICABLE GRADING RULES

Wood shingles of naturally durable wood

1, 2 or 3

Cedar Shake and Shingle Bureau (CSSB)

905.7.5 Application.Wood shingles shall be installed in accordance with this chapter and the manufacturer's instructions. Wood shingles shall be laid with a side lap not less than 11/2 inches (38 mm) between joints in courses, and two joints shall not be in direct alignment in any three adjacent courses. Spacing between shingles shall be not less than1/4 inch to3/8 inch ( 6.4 mm to 9.5 mm). Weather exposure for wood shingles shall not exceed those set in Table 905.7.5(1). Fasteners for untreated (naturally durable) wood shingles shall be box nails in accordance with Table 905.7.5(2). Nails shall be stainless steel Type 304 or 316 or hot-dipped galvanized with a coating weight of ASTM A153 Class D ( 1.0 oz/ft2). Alternatively, two 16-gage stainless steel Type 304 or 316 staples with crown widths7/16 inch ( 11.1 mm) minimum,3/4 inch ( 19.1 mm) maximum, shall be used. Fasteners installed within 15 miles (24 km) of saltwater coastal areas shall be stainless steel Type 316. Fasteners for fire-retardant-treated shingles in accordance with Section 902 or pressure-impregnated-preservative-treated shingles of naturally durable wood in accordance with AWPA U1 shall be stainless steel Type 316. Fasteners shall have a minimum penetration into the sheathing of3/4 inch ( 19.1 mm). For sheathing less than3/4 inch in ( 19.1 mm) thickness, each fastener shall penetrate through the sheathing. Wood shingles shall be attached to the roof with two fasteners per shingle, positioned in accordance with the manufacturer's installation instructions. Fastener packaging shall bear a label indicating the appropriate grade material or coating weight.

TABLE 905.7.5(1)

WOOD SHINGLE WEATHER EXPOSURE AND ROOF SLOPE

ROOFING MATERIAL

LENGTH (inches)

GRADE

EXPOSURE (inches)

3:12 pitch to < 4:12

4:12 pitch or steeper

Shingles of naturally durable wood

16

No. 1

33/4

5

No. 2

31/2

4

No. 3

3

31/2

18

No. 1

41/4

51/2

     

No. 2

4

41/2

No. 3

31/2

4

24

No. 1

53/4

71/2

No. 2

51/2

61/2

No. 3

5

51/2

For SI: 1 inch = 25.4 mm.

TABLE 905.7.5(2)

NAIL REQUIREMENTS FOR WOOD SHAKES AND WOOD SHINGLES

SHAKES

NAIL TYPE AND MINIMUM LENGTH

MINIMUM HEAD SIZE

MINIMUM SHANK DIAMETER

18" straight-split

5d box 13/4"

0.19 "

.080"

18" and 24" handsplit and resawn

6d box 2"

0.19 "

.0915"

24" taper-split

5d box 13/4"

0.19 "

.080"

18" and 24" tapersawn

6d box 2"

0.19 "

.0915"

Shingles

Nail Type and Minimum Length

Minimum Head Size

Minimum Shank Diameter

16" and 18"

3d box 11/4"

0.19 "

.080"

24"

4d box 11/2"

0.19 "

.080"

For SI: 1 inch = 25.4 mm.

905.7.6 Valley flashing.Roof flashing shall be not less than No. 26 gage [ 0.019 inches ( 0.5 mm)] corrosion-resistant sheet metal and shall extend 10 inches (254 mm) from the centerline each way for roofs having slopes less than 12 units vertical in 12 units horizontal (100-percent slope), and 7 inches (178 mm) from the centerline each way for slopes of 12 units vertical in 12 units horizontal (100-percent slope) and greater. Sections of flashing shall have an end lap of not less than 4 inches (102 mm).

905.7.7 Label required.Each bundle of shingles shall be identified by a label of an approved grading or inspection bureau or agency.

905.8 Wood shakes.The installation of wood shakes shall comply with the provisions of this section.

905.8.1 Deck requirements.Wood shakes shall be used only on solid or spaced sheathing. Where spaced sheathing is used, sheathing boards shall be not less than 1-inch by 4-inch (25 mm by 102 mm) nominal dimensions and shall be spaced on centers equal to the weather exposure to coincide with the placement of fasteners. Where 1-inch by 4-inch (25 mm by 102 mm) spaced sheathing is installed at 10 inches (254 mm) on center, additional 1-inch by 4-inch (25 mm by 102 mm) boards shall be installed between the sheathing boards.

905.8.1.1 Solid sheathing required.In areas where the average daily temperature in January is 25°F (-4°C) or less, solid sheathing is required on that portion of the roof requiring an ice barrier.

905.8.2 Deck slope.Wood shakes shall only be used on slopes of three units vertical in 12 units horizontal (25-percent slope) or greater.

905.8.3 Underlayment.Underlayment shall comply with Section 905.1.1.

905.8.3.1 Ice barrier.Where required, ice barriers shall comply with Section 905.1.2.

905.8.4 Interlayment.Interlayment shall comply with ASTM D226, Type I.

905.8.5 Material standards.Wood shakes shall comply with the requirements of Table 905.8.5.

TABLE 905.8.5

WOOD SHAKE MATERIAL REQUIREMENTS

MATERIAL

MINIMUM GRADES

APPLICABLE GRADING RULES

Wood shakes of naturally durable wood

1

Cedar Shake and Shingle Bureau

Tapersawn shakes of naturally durable wood

1 or 2

Cedar Shake and Shingle Bureau

Preservative-treated shakes and shingles of naturally durable wood

1

Cedar Shake and Shingle Bureau

Fire-retardant-treated shakes and shingles of naturally durable wood

1

Cedar Shake and Shingle Bureau

Preservative-treated tapersawn shakes of Southern pine treated in accordance with AWPA Standard U1 (Commodity Specification A, Special Requirement 4.6 )

1or 2

Forest Products Laboratory of the Texas Forest Services

905.8.6 Application.Wood shakes shall be installed in accordance with this chapter and the manufacturer's installation instructions. Wood shakes shall be laid with a side lap not less than 11/2 inches (38 mm) between joints in adjacent courses. Spacing between shakes in the same course shall be3/8 inch to5/8 inch ( 9.5 mm to 15.9 mm) including tapersawn shakes. Weather exposures for wood shakes shall not exceed those set in Table 905.8.6. Fasteners for untreated (naturally durable) wood shakes shall be box nails in accordance with Table 905.7.5(2). Nails shall be stainless steel Type 304, or Type 316 or hot-dipped with a coating weight of ASTM A153 Class D ( 1.0 oz/ft2). Alternatively, two 16-gage Type 304 or Type 316 stainless steel staples, with crown widths7/16 inch ( 11.1 mm) minimum,3/4 inch ( 19.1 mm) maximum, shall be used. Fasteners installed within 15 miles (24 km) of saltwater coastal areas shall be stainless steel Type 316. Wood shakes shall be attached to the roof with two fasteners per shake positioned in accordance with the manufacturer's installation instructions Fasteners for fire-retardant-treated (as defined in Section 902) shakes or pressure-impregnated-preservative-treated shakes of naturally durable wood in accordance with AWPA U1 shall be stainless steel Type 316. Fasteners shall have a minimum penetration into the sheathing of3/4 inch ( 19.1 mm). Where the sheathing is less than3/4 inch ( 19.1 mm) thick, each fastener shall penetrate through the sheathing. Fastener packaging shall bear a label indicating the appropriate grade material or coating weight.

TABLE 905.8.6

WOOD SHAKE WEATHER EXPOSURE AND ROOF SLOPE

ROOFING MATERIAL

LENGTH (inches)

GRADE

EXPOSURE (inches)

4:12 pitch or steeper

Shakes of naturally durable wood

18

No. 1

71/2

24

No. 1

10a

Preservative-treated tapersawn shakes of Southern Yellow Pine

18

No. 1

71/2

24

No. 1

10

18

No. 2

51/2

24

No. 2

71/2

Taper-sawn shakes of naturally durable wood

18

No. 1

71/2

24

No. 1

10

18

No. 2

51/2

24

No. 2

71/2

For SI: 1 inch = 25.4 mm.

a. For 24-inch by3/8-inch handsplit shakes, the maximum exposure is 71/2 inches.

905.8.7 Shake placement.The starter course at the eaves shall be doubled and the bottom layer shall be either 15-inch (381 mm), 18-inch (457 mm) or 24-inch (610 mm) wood shakes or wood shingles. Fifteen-inch (381 mm) or 18-inch (457 mm) wood shakes shall be permitted to be used for the final course at the ridge. Shakes shall be interlaid with 18-inch-wide (457 mm) strips of not less than No. 30 felt shingled between each course in such a manner that felt is not exposed to the weather by positioning the lower edge of each felt strip above the butt end of the shake it covers a distance equal to twice the weather exposure.

905.8.8 Valley flashing.Roof valley flashing shall be not less than No. 26 gage [ 0.019 inch ( 0.5 mm)] corrosion-resistant sheet metal and shall extend not less than 11 inches (279 mm) from the centerline each way. Sections of flashing shall have an end lap of not less than 4 inches (102 mm).

905.8.9 Label required.Each bundle of shakes shall be identified by a label of an approved grading or inspection bureau or agency.

905.9 Built-up roofs.The installation of built-up roofs shall comply with the provisions of this section and the manufacturer's approved installation instructions.

905.9.1 Slope. Built-up roofs shall have a design slope of not less than one-fourth unit vertical in 12 units horizontal (2-percent slope) for drainage, except for coal-tar built-up roofs, which shall have a design slope of a minimum one-eighth unit vertical in 12 units horizontal (1-percent slope).

905.9.2 Material standards.Built-up roof covering materials shall comply with the standards in Table 905.9.2 or UL 55A.

TABLE 905.9.2

BUILT-UP ROOFING MATERIAL STANDARDS

MATERIAL STANDARD

STANDARD

Acrylic coatings used in roofing

ASTM D6083

Aggregate surfacing

ASTM D1863

Asphalt adhesive used in roofing

ASTM D3747

Asphalt cements used in roofing

ASTM D2822; D3019; D4586

Asphalt-coated glass fiber base sheet

ASTM D4601

Asphalt coatings used in roofing

ASTM D1227; D2823; D2824; D4479

Asphalt glass felt

ASTM D2178

Asphalt primer used in roofing

ASTM D41

Asphalt-saturated and asphalt-coated organic felt base sheet

ASTM D2626

Asphalt-saturated organic felt (perforated)

ASTM D226

Asphalt used in roofing

ASTM D312

Coal-tar cements used in roofing

ASTM D4022; D5643

Coal-tar primer used in roofing, dampproofing and waterproofing

ASTM D43

Coal-tar saturated organic felt

ASTM D227

Coal-tar used in roofing

ASTM D450, Type I or II

Glass mat, coal tar

ASTM D4990

Glass mat, venting type

ASTM D4897

Mineral-surfaced inorganic cap sheet

ASTM D3909

Thermoplastic fabrics used in roofing

ASTM D5665; D5726

905.9.3 Application.Built-up roofs shall be installed in accordance with this chapter and the manufacturer's instructions.

905.10 Metal roof panels.The installation of metal roof panels shall comply with the provisions of this section.

905.10.1 Deck requirements.Metal roof panel roof coverings shall be applied to solid or spaced sheathing, except where the roof covering is specifically designed to be applied to spaced supports.

905.10.2 Slope.Minimum slopes for metal roof panels shall comply with the following:

1. The minimum slope for lapped, nonsoldered-seam metal roofs without applied lap sealant shall be three units vertical in 12 units horizontal (25-percent slope).

2. The minimum slope for lapped, nonsoldered-seam metal roofs with applied lap sealant shall be one-half unit vertical in 12 units horizontal (4-percent slope). Lap sealants shall be applied in accordance with the approved manufacturer's installation instructions.

3. The minimum slope for standing-seam roof systems shall be one-quarter unit vertical in 12 units horizontal (2-percent slope).

905.10.3 Material standards.Metal-sheet roof covering systems that incorporate supporting structural members shall be designed in accordance with the Ohio building code. Metal-sheet roof coverings installed over structural decking shall comply with Table 905.10.3(1). The materials used for metal-sheet roof coverings shall be naturally corrosion resistant or provided with corrosion resistance in accordance with the standards and minimum thicknesses shown in Table 905.10.3(2).

TABLE 905.10.3(1)

METAL ROOF COVERING STANDARDS

ROOF COVERING TYPE

STANDARD APPLICATION RATE/THICKNESS

Galvanized steel

ASTM A653 G90 Zinc coated

Stainless steel

ASTM A240, 300 Series alloys

Steel

ASTM A924

Lead-coated copper

ASTM B101

Cold-rolled copper

ASTM B370 minimum 16 oz/sq ft and 12 oz/sq ft high-yield copper for metal-sheet roof-covering systems; 12 oz/sq ft for preformed metal shingle systems.

Hard lead

2 lb/sq ft

Soft lead

3 lb/sq ft

Aluminum

ASTM B209, 0.024 minimum thickness for roll-formed panels and 0.019 -inch minimum thickness for pressformed shingles.

Terne (tin) and terne-coated stainless

Terne coating of 40 lb per double base box, field painted where applicable in accordance with manufacturer's installation instructions.

Zinc

0.027 inch minimum thickness: 99.995 % electrolytic high-grade zinc with alloy additives of copper ( 0.08 - 0.20 %), titanium ( 0.07 % - 0.12 %) and aluminum ( 0.015 %).

For SI: 1 ounce per square foot = 0.305 kg/m2, 1 pound per square foot = 4.214 kg/m2, 1 inch = 25.4 mm, 1 pound = 0.454 kg.

TABLE 905.10.3(2)

MINIMUM CORROSION RESISTANCE

55% aluminum-zinc-alloy-coated steel

ASTM A792 AZ 50

5% aluminum alloy-coated steel

ASTM A875 GF60

Aluminum-coated steel

ASTM A463 T2 65

Galvanized steel

ASTM A653 G-90

Prepainted steel

ASTM A755a

a. Paint systems in accordance with ASTM A755 shall be applied over steel products with corrosion-resistant coatings complying with ASTM A792, ASTM A875, ASTM A463, or ASTM A653.

905.10.4 Attachment.Metal roof panels shall be secured to the supports in accordance with this chapter and the manufacturer's installation instructions. In the absence of manufacturer's installation instructions, the following fasteners shall be used:

1. Galvanized fasteners shall be used for steel roofs.

2. Copper, brass, bronze, copper alloy and 300-series stainless steel fasteners shall be used for copper roofs.

3. Stainless steel fasteners are acceptable for metal roofs.

905.10.5 Underlayment.Underlayment shall comply with Section 905.1.1.

905.11 Modified bitumen roofing.The installation of modified bitumen roofing shall comply with the provisions of this section and the manufacturer's approved installation instructions.

905.11.1 Slope.Modified bitumen roofing shall have a design slope of not less than one-fourth unit vertical in 12 units horizontal (2-percent slope) for drainage.

905.11.2 Material standards.Modified bitumen roofing shall comply with the standards in Table 905.11.2.

TABLE 905.11.2

MODIFIED BITUMEN ROOFING MATERIAL STANDARDS

MATERIAL

STANDARD

Acrylic coating

ASTM D6083

Asphalt adhesive

ASTM D3747

Asphalt cement

ASTM D3019

Asphalt coating

ASTM D1227; D2824

Asphalt primer

ASTM D41

Modified bitumen roof membrane

ASTM D6162; D6163; D6164; D6222; D6223; D6298

905.11.2.1 Base sheet.A base sheet that complies with the requirements of Section 1507.11.2 of the Ohio building code, ASTM D1970, or ASTM D4601 shall be permitted to be used with a modified bitumen cap sheet.

905.11.3 Application.Modified bitumen roofs shall be installed in accordance with this chapter and the manufacturer's instructions.

905.12 Thermoset single-ply roofing.The installation of thermoset single-ply roofing shall comply with the provisions of this section.

905.12.1 Slope.Thermoset single-ply membrane roofs shall have a design slope of not less than one-fourth unit vertical in 12 units horizontal (2-percent slope) for drainage.

905.12.2 Material standards.Thermoset single-ply roof coverings shall comply with ASTM D4637 or ASTM D5019.

905.12.3 Application.Thermoset single-ply roofs shall be installed in accordance with this chapter and the manufacturer's instructions.

905.13 Thermoplastic single-ply roofing.The installation of thermoplastic single-ply roofing shall comply with the provisions of this section.

905.13.1 Slope.Thermoplastic single-ply membrane roofs shall have a design slope of not less than one-fourth unit vertical in 12 units horizontal (2-percent slope).

905.13.2 Material standards.Thermoplastic single-ply roof coverings shall comply with ASTM D4434, ASTM D6754 or ASTM D6878.

905.13.3 Application.Thermoplastic single-ply roofs shall be installed in accordance with this chapter and the manufacturer's instructions.

905.14 Sprayed polyurethane foam roofing.The installation of sprayed polyurethane foam roofing shall comply with the provisions of this section.

905.14.1 Slope.Sprayed polyurethane foam roofs shall have a design slope of not less than one-fourth unit vertical in 12 units horizontal (2-percent slope) for drainage.

905.14.2 Material standards.Spray-applied polyurethane foam insulation shall comply with ASTM C1029, Type III or IV or ASTM D7425.

905.14.3 Application.Foamed-in-place roof insulation shall be installed in accordance with this chapter and the manufacturer's instructions. A liquid-applied protective coating that complies with Table 905.14.3 shall be applied not less than 2 hours nor more than 72 hours following the application of the foam.

TABLE 905.14.3

PROTECTIVE COATING MATERIAL STANDARDS

MATERIAL

STANDARD

Acrylic coating

ASTM D6083

Silicone coating

ASTM D6694

Moisture-cured polyurethane coating

ASTM D6947

905.14.4 Foam plastics.Foam plastic materials and installation shall comply with Section 316.

905.15 Liquid-applied roofing.The installation of liquid-applied roofing shall comply with the provisions of this section.

905.15.1 Slope.Liquid-applied roofing shall have a design slope of not less than one-fourth unit vertical in 12 units horizontal (2-percent slope).

905.15.2 Material standards.Liquid-applied roofing shall comply with ASTM C836, C957, D1227, D3468, D6083, D6694 or D6947.

905.15.3 Application.Liquid-applied roofing shall be installed in accordance with this chapter and the manufacturer's installation instructions.

905.16 Photovoltaic shingles.The installation of photovoltaic shingles shall comply with the provisions of this section, Section 324 and NFPA 70.

905.16.1 Deck requirements.Photovoltaic shingles shall be applied to a solid or closely-fitted deck, except where the roof covering is specifically designed to be applied over spaced sheathing.

905.16.2 Deck slope.Photovoltaic shingles shall be used only on roof slopes of two units vertical in 12 units horizontal (2:12) or greater.

905.16.3 Underlayment.Underlayment shall comply with Section 905.1.1.

905.16.3.1 Ice barrier.Where required, ice barriers shall comply with Section 905.1.2.

905.16.4 Material standards.Photovoltaic shingles shall be listed and labeled in accordance with UL 1703.

905.16.5 Attachment.Photovoltaic shingles shall be attached in accordance with the manufacturer's installation instructions.

905.16.6 Wind resistance.Photovoltaic shingles shall be tested in accordance with procedures and acceptance criteria in ASTM D3161. Photovoltaic shingles shall comply with the classification requirements of Table 905.2.4.1 for the appropriate maximum basic wind speed. Photovoltaic shingle packaging shall bear a label to indicate compliance with the procedures in ASTM D3161 and the required classification from Table 905.2.4.1.

905.17 Building-integrated Photovoltaic (BIPV) roof panels applied directly to the roof deck.The installation of BIPV roof panels shall comply with the provisions of this section, Section 324 and NFPA 70.

905.17.1 Deck requirements.BIPV roof panels shall be applied to a solid or closely-fitted deck, except where the roof covering is specifically designed to be applied over spaced sheathing.

905.17.2 Deck slope.BIPV roof panels shall be used only on roof slopes of two units vertical in 12 units horizontal (17-percent slope) or greater.

905.17.3 Underlayment.Underlayment shall comply with Section 905.1.1.

905.17.3.1 Ice barrier.Where required, an ice barrier shall comply with Section 905.1.2.

905.17.4 Ice barrier.In areas where there has been a history of ice forming along the eaves causing a backup of water, as designated in Table 301.2(1), an ice barrier that consists of not less than two layers of underlayment cemented together or of a self-adhering polymer-modified bitumen sheet shall be used in lieu of normal underlayment and extend from the lowest edges of all roof surfaces to a point not less than 24 inches (610 mm) inside the exterior wall line of the building.

Exception:Detached accessory structures that do not contain conditioned floor area.

905.17.5 Material standards.BIPV roof panels shall be listed and labeled in accordance with UL 1703.

905.17.6 Attachment.BIPV roof panels shall be attached in accordance with the manufacturer's installation instructions.

905.17.7 Wind resistance.BIPV roof panels shall be tested in accordance with UL 1897. BIPV roof panel packaging shall bear a label to indicate compliance with UL 1897.

SECTION 906

ROOF INSULATION

906.1 General.The use of above-deck thermal insulation shall be permitted provided that such insulation is covered with an approved roof covering and complies with FM 4450 or UL 1256.

906.2 Material standards.Above-deck thermal insulation board shall comply with the standards in Table 906.2.

TABLE 906.2

MATERIAL STANDARDS FOR ROOF INSULATION

Cellular glass board

ASTM C552

Composite boards

ASTM C1289, Type III, IV, V or VI

Expanded polystyrene

ASTM C578

Extruded polystyrene board

ASTM C578

Fiber-reinforced gypsum board

ASTM C1278

Glass-faced gypsum board

ASTM C1177

Mineral wool board

ASTM C726

Perlite board

ASTM C728

Polyisocyanurate board

ASTM C1289, Type I or II

Wood fiberboard

ASTM C208

SECTION 907

ROOFTOP-MOUNTED PHOTOVOLTAIC PANEL SYSTEMS

907.1 Rooftop-mounted photovoltaic panel systems. Rooftop-mounted photovoltaic panel systems shall be designed and installed in accordance with Section 324 and NFPA 70.

SECTION 908

REROOFING

908.1 General. Materials and methods of application used for re-covering or replacing an existing roof covering shall comply with the requirements of Chapter 9.

Exceptions:

1. Reroofing shall not be required to meet the minimum design slope requirement of one-quarter unit vertical in 12 units horizontal (2-percent slope) in Section 905 for roofs that provide positive roof drainage.

2. For roofs that provide positive drainage, re-covering or replacing an existing roof covering shall not require the secondary (emergency overflow) drains or scuppers of Section 903.4.1 to be added to an existing roof.

908.2 Structural and construction loads.The structural roof components shall be capable of supporting the roof covering system and the material and equipment loads that will be encountered during installation of the roof covering system.

908.3 Roof replacement.Roof replacement shall include the removal of existing layers of roof coverings down to the roof deck.

Exception:Where the existing roof assembly includes an ice barrier membrane that is adhered to the roof deck, the existing ice barrier membrane shall be permitted to remain in place and covered with an additional layer of ice barrier membrane in accordance with Section 905.

908.3.1 Roof recover.The installation of a new roof covering over an existing roof covering shall be permitted where any of the following conditions occur:

1. Where the new roof covering is installed in accordance with the roof covering manufacturer's approved instructions

2. Complete and separate roofing systems, such as standing-seam metal roof systems, that are designed to transmit the roof loads directly to the building's structural system and do not rely on existing roofs and roof coverings for support, shall not require the removal of existing roof coverings.

3. Metal panel, metal shingle and concrete and clay tile roof coverings shall be permitted to be installed over existing wood shake roofs where applied in accordance with Section 908.4.

4. The application of a new protective roof coating over an existing protective roof coating, metal roof panel, metal roof shingle, mineral surfaced roll roofing, built-up roof, modified bitumen roofing, thermoset and thermoplastic single-ply roofing and spray polyurethane foam roofing system shall be permitted without tear-off of existing roof coverings.

908.3.1.1 Roof recover not allowed.A roof recover shall not be permitted where any of the following conditions occur:

1. Where the existing roof or roof covering is water soaked or has deteriorated to the point that the existing roof or roof covering is not adequate as a base for additional roofing.

2. Where the existing roof covering is slate, clay, cement or asbestos-cement tile.

3. Where the existing roof has two or more applications of any type of roof covering.

908.4 Roof recovering.Where the application of a new roof covering over wood shingle or shake roofs creates a combustible concealed space, the entire existing surface shall be covered with gypsum board, mineral fiber, glass fiber or other approved materials securely fastened in place.

908.5 Reinstallation of materials.Existing slate, clay or cement tile shall be permitted for reinstallation, except that damaged, cracked or broken slate or tile shall not be reinstalled. Any existing flashings, edgings, outlets, vents or similar devices that are a part of the assembly shall be replaced where rusted, damaged or deteriorated. Aggregate surfacing materials shall not be reinstalled.

908.6 Flashings.Flashings shall be reconstructed in accordance with approved manufacturer's installation instructions. Metal flashing to which bituminous materials are to be adhered shall be primed prior to installation.

Replaces: 4101:8-9-01

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