Required Thickness Of Roof Sheathing

For rafters spaced 20 or more inches apart 1 2 or 5 8 inch plywood is recommended.

Required thickness of roof sheathing.

According to 2009 irc table r803 1 minimum thickness of lumber roof sheathing. If the nails penetrate the sheathing but not the studs the minimum plywood thickness that the irc designates is 1 2 inch. 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. Roof sheathing comes in grid marked 4 by 8 foot sheets and should be installed perpendicular to the frame.

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 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. 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.

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. And for wood structural panel sheathing r803 2 2 allowable spans. The typical thickness range for sheathing is 3 8 to 3 4 inch.

Ommended that deformed shank nails be used throughout the entire roof. That s considered to be the minimum. If 8d common nails are specified the nail diameter must be at least 0 131 inch wider than typical 8d pneumatic nails. 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. 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. Sheathing should be a minimum of 19 32 inch thick. Unlike with plywood siding the plywood sheet to be used for sheathing should be at least 3 8 inch thick.

Never attach roof sheathing with staples.