- 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).
- 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.
- 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).
- 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 than 3 /4 inch (19 mm) into the roof sheathing.
| ROOF COVERING | SECTION | MAXIMUM ULTIMATE DESIGN WIND SPEED, Vult < 140 MPH | MAXIMUM ULTIMATE DESIGN WIND SPEED, Vult ≥ 140 MPH |
| Asphalt shingles | R905.2 | ASTM D226 Type I |
| ROOF COVERING | SECTION | MAXIMUM ULTIMATE DESIGN WIND SPEED, Vult < 140 MPH | MAXIMUM ULTIMATE DESIGN WIND SPEED, Vult ≥ 140 MPH |
| Asphalt shingles | R905.2 | 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.
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.
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 4 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: 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.
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s.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 than 3 /4 inch into the roof sheathing.
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 than 3 /4 inch into the roof sheathing.
For SI: 1 inch = 25.4 mm, 1 mile per hour = 0.447 m/s.R905.1.2 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 R301.2(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. 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 not containing conditioned floor area.R905.2 Asphalt Shingles
The installation of asphalt shingles shall comply with the provisions of this section.R905.2.1 Sheathing Requirements
Asphalt shingles shall be fastened to solidly sheathed decks.R905.2.2 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 R905.1.1.
R905.2.3 Underlayment
Underlayment shall comply with Section R905.1.1.R905.2.4 Asphalt Shingles
Asphalt shingles shall comply with ASTM D3462.R905.2.4.1 Wind Resistance of Asphalt Shingles
Asphalt shingles shall be tested in accordance with ASTM D7158. Asphalt shingles shall meet the classification requirements of Table R905.2.4.1 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 R905.2.4.1.
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 R905.2.4.1.
TABLE R905.2.4.1 CLASSIFICATION OF ASPHALT ROOF SHINGLES| MAXIMUM ULTIMATE DESIGN WIND SPEED, Vult FROM FIGURE R301.2(5)A (mph) | MAXIMUM BASIC WIND SPEED, VASD FROM TABLE R301.2.1.3 (mph) | ASTM D7158 a 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 |
- 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.
R905.2.5 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-diameter (9.5 mm) head, complying with ASTM F1667, of a length to penetrate through the roofing materials and not less than 3 /4 inch (19.1 mm) into the roof sheathing. Where the roof sheathing is less than 3 /4 inch (19.1 mm) thick, the fasteners shall penetrate through the sheathing.
R905.2.6 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.
R905.2.7 Ice Barrier
Where required, ice barriers shall comply with Section R905.1.2.R905.2.8 Flashing
Flashing for asphalt shingles shall comply with this section and the asphalt shingle manufacturer's approved installation instructions.
R905.2.8.1 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/m 2 ). Cap flashing shall be corrosion-resistant metal of minimum nominal 0.019-inch (0.5 mm) thickness.
R905.2.8.2 Valleys
- 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 R905.2.8.2.
- 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.
- 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.
| 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 | — | — | 2 1 /2 |
| Painted terne | — | — | 20 |
R905.2.8.3 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 R703.8.2.2. 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 R703.6.3.
R905.2.8.4 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.
R905.2.8.5 Drip Edge
A drip edge shall be provided at eaves and rake edges of shingle roofs. Adjacent segments of drip edge shall be overlapped not less than 2 inches (51 mm). Drip edges shall extend not less than 1 /4 inch (6.4 mm) below the roof sheathing and extend up back onto the roof deck not less than 2 inches (51 mm). Drip edges shall be mechanically fastened to the roof deck at not more than 12 inches (305 mm) o.c. with fasteners as specified in Section R905.2.5. Underlayment shall be installed over the drip edge along eaves and under the drip edge along rake edges.
R905.3 Clay and Concrete Tile
The installation of clay and concrete tile shall comply with the provisions of this section.R905.3.1 Deck Requirements
Concrete and clay tile shall be installed only over solid sheathing or spaced structural sheathing boards.
R905.3.2 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 R905.3.3.
R905.3.3 Underlayment
Underlayment shall comply with Section R905.1.1.R905.3.4 Clay Tile
Clay roof tile shall comply with ASTM C1167.R905.3.5 Concrete Tile
Concrete roof tile shall comply with ASTM C1492.R905.3.6 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 than 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.
R905.3.7 Application
Tile shall be applied in accordance with this chapter and the manufacturer's installation instructions, based on the following:
- Climatic conditions.
- Roof slope.
- Underlayment system.
- 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/m 2 ) 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 R905.3.7.
TABLE R905.3.7 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 |
R905.3.8 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.
R905.4 Metal Roof Shingles
The installation of metal roof shingles shall comply with the provisions of this section.R905.4.1 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.
R905.4.2 Deck Slope
Metal roof shingles shall not be installed on roof slopes below three units vertical in 12 units horizontal (25-percent slope).
R905.4.3 Underlayment
Underlayment shall comply with Section R905.1.1.R905.4.3.1 Ice Barrier
Where required, ice barriers shall comply with Section R905.1.2.R905.4.4 Material Standards
Metal roof shingle roof coverings shall comply with Table R905.10.3(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 R905.10.3(2).
R905.4.5 Application
Metal roof shingles shall be secured to the roof in accordance with this chapter and the approved manufacturer's installation instructions.
R905.4.6 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 R905.10.3(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 than 3 /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.
R905.5 Mineral-Surfaced Roll Roofing
The installation of mineral-surfaced roll roofing shall comply with this section.R905.5.1 Deck Requirements
Mineral-surfaced roll roofing shall be fastened to solidly sheathed roofs.R905.5.2 Deck Slope
Mineral-surfaced roll roofing shall not be applied on roof slopes below one unit vertical in 12 units horizontal (8-percent slope).
R905.5.3 Underlayment
Underlayment shall comply with Section R905.1.1.R905.5.3.1 Ice Barrier
Where required, ice barriers shall comply with Section R905.1.2.R905.5.4 Material Standards
Mineral-surfaced roll roofing shall conform to ASTM D3909 or ASTM D6380, Class M.R905.5.5 Application
Mineral-surfaced roll roofing shall be installed in accordance with this chapter and the manufacturer's instructions.
R905.6 Slate Shingles
The installation of slate shingles shall comply with the provisions of this section.R905.6.1 Deck Requirements
Slate shingles shall be fastened to solidly sheathed roofs.R905.6.2 Deck Slope
Slate shingles shall be used only on slopes of four units vertical in 12 units horizontal (33-percent slope) or greater.
R905.6.3 Underlayment
Underlayment shall comply with Section R905.1.1.R905.6.3.1 Ice Barrier
Where required, ice barriers shall comply with Section R905.1.2.R905.6.4 Material Standards
Slate shingles shall comply with ASTM C406.R905.6.5 Application
Minimum headlap for slate shingles shall be in accordance with Table R905.6.5. 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.
SLATE SHINGLE HEADLAP| SLOPE | HEADLAP (inches) |
| 4:12 ≤ slope < 8:12 | 4 |
| 8:12 ≤ slope < 20:12 | 3 |
| Slope ≥ 20:12 | 2 |
R905.6.6 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.
R905.7 Wood Shingles
The installation of wood shingles shall comply with the provisions of this section.R905.7.1 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.
R905.7.1.1 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.
R905.7.2 Deck Slope
Wood shingles shall be installed on slopes of three units vertical in 12 units horizontal (25-percent slope) or greater.
R905.7.3 Underlayment
Underlayment shall comply with Section R905.1.1.R905.7.3.1 Ice Barrier
Where required, ice barriers shall comply with Section R905.1.2.R905.7.4 Material Standards
Wood shingles shall be of naturally durable wood and comply with the requirements of Table R905.7.4. WOOD SHINGLE MATERIAL REQUIREMENTS| MATERIAL | MINIMUM GRADES | APPLICABLE GRADING RULES |
| Wood shingles of |
R905.7.5 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 1 1 /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 than 1 /4 inch to 3 /8 inch (6.4 mm to 9.5 mm). Weather exposure for wood shingles shall not exceed those set in Table R905.7.5(1). Fasteners for untreated (naturally durable) wood shingles shall be box nails in accordance with Table R905.7.5(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/ft 2 ). Alternatively, two 16-gage stainless steel Type 304 or 316 staples with crown widths 7 /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 R902 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 of 3 /4 inch (19.1 mm). For sheathing less than 3 /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.
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 | 3 3 /4 | 5 |
| No. 2 | 3 1 /2 | 4 | ||
| No. 3 | 3 | 3 1 /2 | ||
| 18 | No. 1 | 4 1 /4 | 5 1 /2 | |
| No. 2 | 4 | 4 1 /2 | ||
| No. 3 | 3 1 /2 | 4 | ||
| 24 | No. 1 | 5 3 /4 | 7 1 /2 | |
| No. 2 | 5 1 /2 | 6 1 /2 | ||
| No. 3 | 5 | 5 1 /2 | ||
| SHAKES | NAIL TYPE AND MINIMUM LENGTH | MINIMUM HEAD SIZE | MINIMUM SHANK DIAMETER |
| 18" straight-split | 5d box 1 3 /4" | 0.19" | .080" |
| 18" and 24" handsplit |
R905.7.6 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).
R905.7.7 Label Required
Each bundle of shingles shall be identified by a label of an approved grading or inspection bureau or agency.
R905.8 Wood Shakes
The installation of wood shakes shall comply with the provisions of this section.R905.8.1 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.
R905.8.1.1 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.
R905.8.2 Deck Slope
Wood shakes shall only be used on slopes of three units vertical in 12 units horizontal (25-percent slope) or greater.
