For roof deck construction, plywood should be a minimum of 12.7 mm (1/2 in) thick. The proper thickness of the plywood panels required for a specific roof is determined by the design loads for the roof and the distance between the supporting members.
Oriented Strand Board (OSB)
An oriented strand board roof deck is composed of panels made from layers of compressed, glued woodstrands. These strand layers are oriented at right angles to one another before being glued and formed into panels. Oriented strand board for roof decks should be a minimum of 12.7 mm (1/2 in) thick. The proper thickness of the oriented strand board panels is determined by the design loads anticipated for the roof and the distance between the supporting members.
Structural Wood Plank
Decking material for low-slope roof deck construction should be sound, air-dried or kiln-dried, solid-sawn lumber, with tongue-and-groove or splined side joints, ship-lap or straight-edge butt joint. End joints of each piece of decking should be staggered. End joints should be centered over the supporting members. All boards should be securely fastened.