Roofing Do You Need To Use Treated Plywood

Use pressure treated wood in any situation where there s direct contact between the wood and anything that could supply moisture.

Roofing do you need to use treated plywood.

Perry mastrovito design pics getty images. Wood for any outdoor project should be pressure treated. These tips cover plywood characteristics and proper installation of plywood. If there is rotten decking the shingles are most likely letting moisture in.

Where to use pressure treated wood while many homeowners wonder if they should use pressure treated wood for a specific project the answer is simple. Moisture causes wood to rot and rotten wood absorbs water even more readily than fresh wood. It will support roof. For rafters spaced 20 or more inches apart 1 2 or 5 8 inch plywood is recommended.

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. Read be informed and extract maximum useful life from your plywood project. Modern metal roofs are expected to last 30 years or longer. The most common rafter spacing is 24 inches and 5 8 inch plywood is recommended for that.

The sawdust from pressure treated wood is an irritant to the eyes skin and nose. Pressure treated wood is required whenever you attach framing lumber or furring strips directly to concrete or other exterior masonry walls below grade. Wood for indoor projects should be left as is. 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.

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. If plywood is not dealt with properly it can swell and create major problems with roofing flooring or siding. 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. Note that this requirement is only for exterior walls as these may wick moisture onto the lumber.