The plywood sheathing place over the floor joists or roof rafters. Floor decking is usually one or two 5/8" plywood sheets thick. Roof decking is 3/8" with galvanized roofing and 1/2" with shingles, rubberized or built-up roofing.
Decking materials are what forms the flooring of a deck, often 2x6 or 2x8 boards. This term should not be confused with the word, deck, that refers to the entire structure. The decking, or deck flooring, is the uppermost element of the deck structure, except for the railings. Proceeding in order from the bottom to the top, the following elements support the decking: • concrete footings (underground) • concrete piers • posts • girder • header board • joists
Lumber used primarily and roofing and flooring applications. Most common sizes of decking are: 5/4 X 6, 2 X 6, 2 X 8, 3 X 6, and 4 X 6. Decking is often sawn with tongues and grooves and in various patterns (double tongue–and–groove and single tongue–and–groove). Patterns are sometimes sawn on the face to be exposed. These patterns are often grooves or various shapes, depths and sizes.