What Is Oriented Strand Board?
Oriented Strand Board, also referred to as OSB, is manufactured from fast-growing trees such as the aspen poplar, southern yellow pine, mixed hardwoods and other suitable species. It is equivalent in strength to regular wood panels (i.e. plywood) although its big advantage is cost. OSB is significantly cheaper than plywood. This is mainly due to the wood products that make up the panels. Plywood uses old growth trees that are fairly expensive while OSB uses fast growth trees that have little commercial value other than as a source for OSB strands. OSB is made by coating wood chips (known as strands) with MDI and/or phenol formaldehyde, then arranging consecutive strand layers roughly perpendicular to each other, and finally pressing the strands under high temperature and high pressure to form boards. The MDI binds the strands together by reacting with water on the strands to form polyurea and with hydroxyl groups in the wood lignin to form polyurethane. These bonds form a chemical matr
