Roof Sheathing Thickness

Allowable spans for wood structural panels for roof sheathing.

Roof sheathing thickness.

Roof sheathing comes in grid marked 4 by 8 foot sheets and should be installed perpendicular to the frame. Sheathing should be a minimum of 19 32 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. That s considered to be the minimum.

Most roofs will be sheathed in plywood at least 3 8 inch thick. The minimum thickness of lumber roof sheathing should conform to table 1 below. Roof sheathing conforming with this table shall be deemed to meet the design criteria of section 2304 7. Roof sheathing thickness unlike with plywood siding the plywood sheet to be used for sheathing should be at least 3 8 inch thick.

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. That will suffice on a roof with rafters set 16 inches apart with minimal roof loads. 1 inch 25 4 mm 1 pound per square foot 0 0479 kn m2.

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.