Oriented-strand Board
Definition and meaning of Oriented-strand Board in real estate.
Oriented-strand board, commonly abbreviated as OSB, is a type of engineered wood panel made by compressing and gluing layers of wood strands together in specific orientations. It is widely used in residential construction as sheathing for roofs, walls, and subfloors.
In more detail
OSB was developed as a more cost-effective and resource-efficient alternative to traditional plywood. Because it uses smaller strands of wood from fast-growing trees, it is cheaper to manufacture and has a consistent structural quality with no knots or core voids. OSB panels are typically sold in standard four-by-eight-foot sheets and are often treated with water-resistant resins to prevent swelling from temporary weather exposure.
While it is structurally comparable to plywood for sheathing applications, OSB can absorb water more slowly but hold moisture longer, which can cause the edges to swell if exposed to heavy rain during construction.
Key facts
| Category | Property Types & Construction |
|---|---|
| Also known as | OSB, waferboard (historically) |
| Common uses | Roof deck sheathing, exterior wall sheathing, and subflooring |
| Watch out for | Edge swelling if exposed to prolonged moisture |
A framing crew installs sheets of oriented-strand board over the wooden roof rafters to create a solid deck for nailing down asphalt shingles.
Frequently asked questions
Is oriented-strand board as strong as plywood?
Yes, for most residential construction applications like sheathing and subfloors, OSB is recognized by building codes as structurally equivalent to plywood.
Does oriented-strand board rot easily?
Like all wood products, OSB will decay if it remains wet for long periods, though the resins used in modern manufacturing provide temporary resistance to moisture during construction.