Minimum Roof Sheathing Thickness

Roofs are framed with rafters or trusses which are rafters joined by internal braces so they install as a single component.

Minimum roof sheathing 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 international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process. Floor or roof sheathing conforming with this table shall be deemed to meet the design criteria of section 2304 7. Osb roof decking thickness 7 16 1 2 or 5 8 if were using osb we get 9 16 we dont worry about getting both 7 16 and 9 16 for walls then the roof we just get all of the same.

Sheathing should be a minimum of 19 32 inch thick. The minimum plywood for roofing. According to 2009 irc table r803 1 minimum thickness of lumber roof sheathing. This way no worrying about grabbing scraps to fill in small spots and not having the correct thickness.

The typical thickness range for sheathing is 3 8 to 3 4 inch. 1 inch 25 4 mm. And for wood structural panel sheathing r803 2 2 allowable spans. 8d ring shank nails should be used instead.

You would go to table r503 2 1 1 1 to determine minimum nominal panel thickness. Building codes for roofing reqiure a minimum 1x4 and the spaces between battens should not exceed 3 1 2 inches figure 2 46 wood shingles over spaced sheathing and figure 2 47 wood shakes installed over wood sheathing are illustrated below. Never attach roof sheathing with staples. Roof sheathing comes in grid marked 4 by 8 foot sheets and should be installed perpendicular to the frame.

Rafters run from the peak of the roof. Many code requirements are not inspected. Installation details shall conform to sections 2304 7 1 and 2304 7 2 for floor and roof sheathing respectively.