Plywood is a type of engineered wood that is made from thin sheets of wood that have been glued together on top of each other. The grain on each sheet of wood will run at a right angle to the previous layer, giving it additional strength. Plywood contains at least three sheets of wood but will commonly contain upwards of five.
Why is Plywood Used in Roofing?
Roofs are built from rafters and trusses, which make up the framework of the roof, but a flat deck then needs to be laid on top of the frame, which the final roof material can be fixed to, for example, tiles or felt. Plywood is an ideal material for the deck of a roof because it is inexpensive and durable. Using solid wood would be a waste in this instance because the deck of the roof won’t be seen once the roof is complete, so it doesn’t matter what it looks like. Plywood offers the strength required to hold the load of the material which will go on top of it, along with heavy snowfall or ice.
Plywood has a good level of water resistance, which is useful when used in outdoor applications such as roofing. In the event that it does expand due to moisture, it does so evenly so that the structure of the roof is not affected. It also dries out quickly, which reduces the chance of mold buildup and other moisture-related issues.
Plywood is also easy to work with and can be cut to size using handheld saws or circular saws. The standard size for sheets of plywood is four feet by eight feet, which makes it a reasonable size to work with while also covering a decent surface area on the roof. Larger sizes are available, though less common. Plywood is also available in various thicknesses to suit different loads.
