9 Best Of How Thick Should Plywood Be On A Flat Roof New Update 2021. Never attach roof sheathing with staples. Dec 06 2018 OSB and plywood come in thicknesses ranging from 516 to 34 inch and the thickness needed for a particular roof depends on several factors including rafter spacing expected load and roof design.
Longitudinal joints should occur on the centre line of supporting joists. Steeper rather than flatter roofs will have lesser load per sq. The plywood is normally square-edged.
Everyone including myself in my metro and sorrounding will typically use 12 I have come across 38.
Generally plywood comes in 4 by 8-foot sheets and in a variety of grades. Roof sheathing comes in grid-marked 4-by-8-foot sheets and should be installed perpendicular to the frame. I use 12 under standing seam with no problems we get maybe 60. Plywood typically comes in 48 ft.