Roof sheathing comes in grid marked 4 by 8 foot sheets and should be installed perpendicular to the frame.
Roof sheathing thickness.
Roof sheathing conforming with this table shall be deemed to meet the design criteria of section 2304 7.
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.
Most roofs will be sheathed in plywood at least 3 8 inch thick.
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.
Allowable spans for wood structural panels for roof sheathing.
1 inch 25 4 mm 1 pound per square foot 0 0479 kn m2.
Most builder s use 7 16 osb with clips if a heavy roof covering applied or called for on plans.
The typical thickness range for sheathing is 3 8 to 3 4 inch.
Roof sheathing thickness unlike with plywood siding the plywood sheet to be used for sheathing should be 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.
The minimum thickness of lumber roof sheathing should conform to table 1 below.