OSB

OSB (oriented strand board) is defined as an engineered wood panel made from compressed layers of wood strands bonded with waterproof resin adhesive, used as roof decking and wall sheathing. Standard roof-grade OSB is 7/16-inch thick and rated for 24-inch on-center rafter spacing. OSB is the most commonly used roof decking material in North America due to its lower cost compared to plywood, though it is more susceptible to moisture damage and edge swelling when exposed to prolonged water contact.