Should I Use Treated Plywood For Roof

Osb and plywood come in thicknesses ranging from 5 16 to 3 4 inch and the thickness needed for a particular roof depends on several factors including rafter spacing expected load and roof design.

Should i use treated plywood for roof.

Can pressure treated plywood be used as roof decking without being destroyed by the dry heat a roof is exposed to. This wood is just like regular framing lumber except it has been factory treated to reduce or prevent rot. Wood for any outdoor project should be pressure treated. The sawdust from pressure treated wood is an irritant to the eyes skin and nose.

One of the nice things about plywood is the variety of options you can buy. The roof is structurally sound otherwise. Use pressure treated 3 4 inch construction grade exterior plywood for the floor. The thickness of plywood used for roof decking depends on the roof slope the spacing of rafters and the weight of other material to be put over the decking as well as the design load the.

On the shed walls use exterior rated 1 2 inch plywood for a waterproof finished look and 3 4 inch cdx plywood on the roof for strength. I have a low sloped roof to replace where the 1 2 osb has rotted out at the edges and water has been penetrating behind the gutter and i am afraid will soon be into the interior walls possibly even rotting the ends of the trusses sitting on the top plate. Any time wood is used in applications that put it within a few inches of soil it should be pressure treated lumber. It s solid won t sag and protects the substructure and is easy to sweep.

Am i correct in assuming that you should not use treated wood for furring strips underneath a metal roof. Where to use pressure treated wood. Wood for indoor projects should be left as is. While many homeowners wonder if they should use pressure treated wood for a specific project the answer is simple.

The sole exception to this is pressure treated cdx which can survive for decades without even a protective coating. Plywood is made with an odd number of layers for optimal strength and performance. I am installing standing seam over an old shingled roof which is not flat in some areas due to warping of the old sawmill rough lumber used in the original construction. Only use cdx plywood for the interior of a house where water damage is far less likely.

This is why non pressure treated wood is still required for use indoors and why builders recommended that you only use pressure treated lumber for the support structure of a deck and switch to untreated wood for the surface. Up until 2000 plywood held the majority of the market for wall roof and floor sheathing when it was surpassed by osb which as of 2018 held about 75 of the market share.