ARAC Roof It Forward Case Studies: Roof Decking: Plywood VS OSB

Building codes, the Engineered Wood Association, architects and most builders rate plywood and oriented strand board (OSB) equal in strength and durability. Like-thicknesses of these two products can span the same distances between studs or rafters, weigh about the same and offer similar nail-holding abilities. OSB has its advantages. Having a painted sealed edge protects against swelling due to water entering the edges. Some panels have a rough surface making them easier and safer to walk on. OSB panels have lines at 16- and 24-in. intervals so you know where underlying studs, rafters and joists are for nailing. In our areas 1/2-in. OSB costs a few dollars less per sheet than 1/2-in. plywood. And OSB is available in larger sheets. OSB has swell if exposed to water for a long period of time. Plywood will de-laminate if exposed to water for longer periods. Care should always betaken to store both on the job site covered and under-layment should be installed as quickly as possible. Neither should be stored out side in the rain.