Required Thickness Of Roof Sheathing

The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures.

Required thickness of roof sheathing. In practice many builders default to 1 2 inch plywood even if they plan. The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process. You would go to table r503 2 1 1 1 to determine minimum nominal panel thickness. The most common rafter spacing is 24 inches and 5 8 inch plywood is recommended for that.

8d ring shank nails should be used instead. Many code requirements are not inspected. 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. Unlike with plywood siding the plywood sheet to be used for sheathing should be at least 3 8 inch thick.

If 8d common nails are specified the nail diameter must be at least 0 131 inch wider than typical 8d pneumatic nails. For rafters spaced 20 or more inches apart 1 2 or 5 8 inch plywood is recommended. Screws can be used for typical layout of roof sheathing panels on gable end roof typical layout of roof sheathing panels on hip roof. Never attach roof sheathing with staples.

That s considered to be the minimum. Wood structural panel roof sheathing shall be bonded by exterior glue. 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. According to 2009 irc table r803 1 minimum thickness of lumber roof sheathing.

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. If the nails penetrate the sheathing but not the studs the minimum plywood thickness that the irc designates is 1 2 inch. The typical thickness range for sheathing is 3 8 to 3 4 inch.

Sheathing should be a minimum of 19 32 inch thick.