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.

The typical thickness range for sheathing is 3 8 to 3 4 inch. 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. 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. In practice many builders default to 1 2 inch plywood even if they plan.

Unlike with plywood siding the plywood sheet to be used for sheathing should be at least 3 8 inch thick. Many code requirements are not inspected. 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. If the nails penetrate the sheathing but not the studs the minimum plywood thickness that the irc designates is 1 2 inch.

And for wood structural panel sheathing r803 2 2 allowable spans. The most common rafter spacing is 24 inches and 5 8 inch plywood is recommended for that. Screws can be used for typical layout of roof sheathing panels on gable end roof typical layout of roof sheathing panels on hip roof. According to 2009 irc table r803 1 minimum thickness of lumber roof sheathing.

The eaves membrane should extend into the house 24 inches past the interior face of the outside wall. 8d ring shank nails should be used instead. Wood structural panel roof sheathing shall be bonded by exterior glue. Roof sheathing comes in grid marked 4 by 8 foot sheets and should be installed perpendicular to the frame.

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.