Why use Plywood
Plywood is a low-cost material that is water-resistant and has structural stability. This makes it a favorite amongst builders as a material used on the exterior portions of houses.
Though the structure of the roof takes the brunt of it, the strength of plywood is also relied upon to support the rest of the roofing system. The material gets its strength from the way it is built.
Plywood is made up of layers of wood that are glued together, with the grains in each layer running in alternate directions.
This also ensures that the strength of the wood is evenly distributed. This method of layering also minimizes the amount the wood shrinks and expands because of temperature changes and makes it less likely to split when it is nailed into.
Different Types and Styles of Roofs for Homes
Plywood is also known to perform well when exposed to moisture over long periods of time. Unlike other wood, because of the way it is made, plywood expands evenly and dries down fast, returning to its original size all over rather than in some areas.
Types of Plywood used for Roofing
There are multiple types of plywood available in the market like shuttering plywood, general plywood or structural plywood.
Shuttering plywood is used to hold concrete, while general plywood is used for non-structural roles. Like its name, structural plywood is used for structural purposes.
Structural plywood is put through tests to prove structural integrity and meets building regulations, while general plywood doesn’t go through the same process.
CDX is the grade of plywood most commonly used for roofing (CDX plywood means it is Construction Grade for exterior purposes).
The wood is graded on each side from A to D, depending on the level of imperfections, (A being free of all imperfections and knots and D being un-sanded and considerably defected).
One side of the plywood could be A grade with the other side a D grade. This works if the lower graded side is used on the inside of the roof, while the high grade faces the outside.
The C in CDX represents the grade given to the front of the plywood, the D represents the grade given to the back of the plywood and the X represents the type of glue used to bond the layers together.
There is one more type of plywood that has been known to be used in roofing, which is Fire-Retardant Plywood or FRT Plywood. This kind of plywood can be life-saving in the time of a crisis and is sometimes required in certain areas.
