Required Thickness Of Roof Sheathing

If 8d common nails are specified the nail diameter must be at least 0 131 inch wider than typical 8d pneumatic nails.

Required thickness of roof sheathing.

Never attach roof sheathing with staples. Wood structural panel roof sheathing shall be bonded by exterior glue. 8d ring shank nails should be used instead. The typical thickness range for sheathing is 3 8 to 3 4 inch.

In practice many builders default to 1 2 inch plywood even if they plan. You would go to table r503 2 1 1 1 to determine minimum nominal panel thickness. This minimum will only work if the rafters are set 16 inches apart at most and if the roof doesn t have too much load. If the nails penetrate the sheathing but not the studs the minimum plywood thickness that the irc designates is 1 2 inch.

Screws can be used for typical layout of roof sheathing panels on gable end roof typical layout of roof sheathing panels on hip roof. The most common rafter spacing is 24 inches and 5 8 inch plywood is recommended for that. Roof sheathing comes in grid marked 4 by 8 foot sheets and should be installed perpendicular to the frame. Ommended that deformed shank nails be used throughout the entire roof.

In areas where the average daily temperature in january is 25 f or less solid sheathing is required on the lower section of the roof to support an eaves membrane. That s considered to be the minimum. For rafters spaced 20 or more inches apart 1 2 or 5 8 inch plywood is recommended. According to 2009 irc table r803 1 minimum thickness of lumber roof sheathing.

Many code requirements are not inspected. Sheathing should be a minimum of 19 32 inch thick. Roof sheathing conforming to the provisions of table 2304 7 1 2304 7 2 2304 7 3 or 2304 7 5 shall be deemed to meet the requirements of this section. And for wood structural panel sheathing r803 2 2 allowable spans.

Unlike with plywood siding the plywood sheet to be used for sheathing should be at least 3 8 inch thick.