Roofing Do You Need To Use Treated Plywood

Interior walls are within a climate controlled environment and are presumed to be free of moisture.

Roofing do you need to use treated plywood.

Moisture causes wood to rot and rotten wood absorbs water even more readily than fresh wood. This means posts in contact or buried underground obviously but it also includes any lumber touching concrete or masonry since it s porous and wicks water like a sponge. Modern metal roofs are expected to last 30 years or longer. For rafters spaced 20 or more inches apart 1 2 or 5 8 inch plywood is recommended.

Wood for indoor projects should be left as is. While metal roofing doesn t require plywood underlayment there are circumstances in which you may wish to install plywood to anticipate future roofing needs or to offer additional soundproofing. If there is rotten decking the shingles are most likely letting moisture in. Pressure treated wood is required whenever you attach framing lumber or furring strips directly to concrete or other exterior masonry walls below grade.

Use pressure treated wood in any situation where there s direct contact between the wood and anything that could supply moisture. Rotted plywood cannot support the weight of a roof the way healthy wood can nor can it safely grip the nails put into the roof and keep them held firm. Perry mastrovito design pics getty images. It will support roof.

The sawdust from pressure treated wood is an irritant to the eyes skin and nose. If plywood is not dealt with properly it can swell and create major problems with roofing flooring or siding. 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. I do remember decades ago when us steel and kaiser aluminum were big metal panel roofing suppliers and aca cca which are salts treated wood was first commonly available they did recommend but not insist for warranty coverage that narrow strips of roofing felt be put across the top of the firring strips to avoid direct contact and possible corrosion.

These tips cover plywood characteristics and proper installation of plywood. Read be informed and extract maximum useful life from your plywood project. Correction to this wood product problem can clean your wallet. Note that this requirement is only for exterior walls as these may wick moisture onto the lumber.