Sloped roofs wouldn’t be complete without decking. But why is this component so important?
WHAT IS ROOF DECKING?
Roof decking, also known as sheathing, is the boards that fill the spaces between the roof’s structural components, such as trusses and joists. Decking provides a flat plane to which shingles can be fastened and workers can use as a path. For metal roofing systems, decking provides the added benefit of noise absorption, making the roof much quieter during rainfall.
DIFFERENT TYPES OF ROOF DECKING
There are many types of materials that can be used for roof decking, some of which are ideal for certain types of residential roofing systems.
Oriented strand board (OSB) – OSB is the most common type of material used for roof decking. It’s durable and readily available, and has relatively low costs. OSB is made of interwoven strands of wood bonded with adhesive.
Plywood – Half-inch construction-grade plywood is another common building material used for roof decking. The installation methods are the same as OSB, including the standard spacing required for thermal expansion and contraction.
Tongue and groove – Tongue and groove decking is built from two-by-six boards. Each board has a “tongue” on one end and a “groove” on the other that locks into each other during installation. This type of decking is used on roofs that do not have a ceiling. The boards have an aesthetic effect when viewed indoors.
Plank sheathing – While not as popular as it was before the 1970s, plank sheathing remains in use for certain types of roofs, such as wood shakes. Instead of a flat plane, the wood planks are spaced about one and a half inches apart.
DECKING DOESN’T ALWAYS NEED TO BE REPLACED
A standard roof deck is usually good for two installations. This means if your last roof replacement included new decking material, and, assuming the roofing structure is still structurally sound, then the same roof deck can be used for the next installation. Using it for a third time is not recommended as it would be too perforated from the previous installations. Your roofing contractor will determine the condition of your roof prior to giving you a quotation.