5 Best Of What Size Plywood Should Be Used On A Roof Best Images PNG. 3-Ply 3-ply is one of the most common types of plywood. Half-inch is rated for a 32.
The spacing of your purlins depends on the expected snow and wind load. If you think of the way that plywood is manufactured every 18 thickness is a different layer that is rotated 90 degrees which is what gives plywood its bi-directional strength and dimensional stability. Span in the same application.
With 58 plywood you.
With edge support and the same snow load 38-inch OSB can be used. May actually cost less than the 38. If you think of the way that plywood is manufactured every 18 thickness is a different layer that is rotated 90 degrees which is what gives plywood its bi-directional strength and dimensional stability. Thickness often depends on how spaced apart the rafters are.