Wood shakes shall comply with the requirements of Table R905.8.5.
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, Use Category 3B and Section 5.6)||1 or 2||Forest Products Laboratory of the Texas Forest Services|
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 be 3/8 inch to 5/8 inch (9.5 mm to 15.9 mm) including tapersawn shakes. Weather exposures for wood shakes shall not exceed those set in Table R905.8.6. Fasteners for untreated (naturally durable) wood shakes shall be box nails in accordance with Table R905.7.5(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 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 salt water 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 R902) shakes or pressure-impregnated-preservative-treated shakes of naturally durable wood in accordance with AWPA U1 shall be stainless steel Type 316. All fasteners shall have a minimum penetration into the sheathing of 3/4 inch (19.1 mm). Where the sheathing is less than 3/4 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.
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|
|Preservative-treated tapersawn shakes of|
Southern Yellow Pine
|Taper-sawn shakes of naturally durable wood||18||No. 1||71/2|
For SI: 1 inch = 25.4 mm.
- For 24-inch by 3/8-inch handsplit shakes, the maximum exposure is 71/2 inches.