Replacing Roof Boards Plywood

Open spaces form between the once tightly fitted shiplap boards.

Replacing roof boards plywood.

Today a shiplap roof is usually 60 years old. Screw the rafter to the chimney cleat as well. Over time shiplap fir wood resin dissipates causing the boards to shrink crack form knot holes and become extremely brittle. If you were able to keep the removed section in one piece measure it.

If not climb the roof and measure the opening so you can cut the replacement piece to be a perfect fit. It can withstand moisture for a brief period of time but may become warped and delaminated with consistent exposure to the elements. Rotted plywood can cause a number of issues. If you can see original wood shingles on the underside of your roof when you re up in the attic you ll need not only to tear everything off but also to install new plywood decking all of which likely adds 5 000 or more to your costs.

Now it s time to replace the roof plywood and any other damaged wood in the roof area. Cdx plywood is a construction grade type of plywood that is designed for exposure to the elements. The keyword here is solid it used to be standard to use shiplap 1 boards tongue groove or other boards for the roof deck. After the 1960s the predominant residential roofing substrate became 1 2 cdx plywood.

Make minor repairs on the roof if it is in good condition. 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. Moisture causes wood to rot and rotten wood absorbs water even more readily than fresh wood. Clamp a 1 by backing board in place and screw the new rafter to it.

As roofing contractors in seattle we are often asked why do we need plywood over our old solid sheathing. This particular type of plywood is crafted from layers of wood stacked on top of one another with alternating grain patterns in each layer. I ll be on the road for a few months and won t have time to complete these posts until after but for those of you who ve written wanting to see the rest of the project hopefully this is better than nothing. Select plywood or oriented strand board that is the same thickness as the wood you are replacing.

The tear off gets a lot more complicated if you have something other than asphalt up there. These 8 to 12 inch wide boards were nailed together tight. If not replace bad wood with new plywood sheathing or 1 x 6 sheathing boards whichever is applicable to your type of roof.