Required Thickness Of Roof Sheathing

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.

Required thickness of roof sheathing.

Roof sheathing comes in grid marked 4 by 8 foot sheets and should be installed perpendicular to the frame. And for wood structural panel sheathing r803 2 2 allowable spans. Wood structural panel roof sheathing shall be bonded by exterior glue. 8d ring shank nails should be used instead.

If the nails penetrate the sheathing but not the studs the minimum plywood thickness that the irc designates is 1 2 inch. You would go to table r503 2 1 1 1 to determine minimum nominal panel thickness. 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. The most common rafter spacing is 24 inches and 5 8 inch plywood is recommended for that.

In practice many builders default to 1 2 inch plywood even if they plan. According to 2009 irc table r803 1 minimum thickness of lumber roof sheathing. If 8d common nails are specified the nail diameter must be at least 0 131 inch wider than typical 8d pneumatic nails. 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.

Unlike with plywood siding the plywood sheet to be used for sheathing should be at least 3 8 inch thick. Ommended that deformed shank nails be used throughout the entire roof. That s considered to be the minimum. Screws can be used for typical layout of roof sheathing panels on gable end roof typical layout of roof sheathing panels on hip roof.

Sheathing should be a minimum of 19 32 inch thick. For rafters spaced 20 or more inches apart 1 2 or 5 8 inch plywood is recommended. Many code requirements are not inspected. Never attach roof sheathing with staples.

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.