Roof Sheathing Thickness

1 inch 25 4 mm 1 pound per square foot 0 0479 kn m2.

Roof sheathing thickness.

That s considered to be the minimum. Allowable spans for wood structural panels for roof sheathing. Most roofs will be sheathed in plywood at least 3 8 inch thick. Uniform load deflection limitations 1 180 of span under live load plus dead load 1 240 under live load only.

Loads will vary with the pitch of the roof. Roof sheathing thickness unlike with plywood siding the plywood sheet to be used for sheathing should be at least 3 8 inch thick. 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. Roof sheathing comes in grid marked 4 by 8 foot sheets and should be installed perpendicular to the frame.

Most builder s use 7 16 osb with clips if a heavy roof covering applied or called for on plans. Otherwise no clips just be sure to space all edges 1 8 as listed right on the sheathing label which goes down so the inspector can read it from inside it s also the waxed side which is safer. The typical thickness range for sheathing is 3 8 to 3 4 inch. You may be able to measure the thickness of the roof decking material with a simple ruler as seen in the photo below taken during an actual inspection.

Sheathing should be a minimum of 19 32 inch thick.