(a) Roof rafters shall be covered with five-eighths inch roof sheathing not more than twelve inches in width, laid closed for tile, slate, asbestos-cement or asphalt shingles; or one by three-inch shingle lath for wood shingle roof, spaced according to shingle exposure. All roof sheathing and shingle lath shall be securely nailed to rafters at each bearing. Boards over eight inches wide shall be triple-nailed. Twelve-inch sheathing used must be secured with four 8d nails.
(b) Plywood can be of Interior Type, except that Exterior Type shall be used when any surface or edge is permanently exposed to weather. The allowance spans shall comply with the following table:
Maximum Spans (in.) | Load (psf) | |||
Panel Indentification Index Roof/Floor | Edges Blocked | Edges Unblocked | Total Load | Live Load |
12/0 | 12 | 12 | 130 | 100 |
16/0 | 16 | 16 | 75 | 55 |
20/0 | 20 | 20 | 55 | 45 |
24/0 | 24 | 24 | 60 | 45 |
30/12 | 30 | 26 | 55 | 40 |
32/16 | 32 | 28 | 50 | 40 |
36/16 | 36 | 30 | 50 | 35 |
42/20 | 42 | 32 | 45 | 35 |
48/24 | 48 | 36 | 40 | 40 |
SUPPLEMENTARY DATA:
Dead load for shingle roof, including framing: 6-10 lbs. per sq. ft.
Dead load for slate roof, including framing: 12-15 lbs. per sq. ft.
Dead load for tile roof, including framing: 20-30 lbs. per sq. ft.
Dead load for tar and gravel, including framing: 10-12 lbs. per sq. ft.
(Ord. 42-1981. Passed 2-23-81.)