OSB (Oriented Strand Board)
An engineered wood panel made from compressed layers of wood strands arranged in specific orientations and bonded with resin adhesives.
In-Depth Explanation
OSB is a widely used structural panel in residential and commercial construction, serving as wall sheathing, roof decking, and subflooring. The strands are oriented in perpendicular layers, similar to plywood's cross-laminated veneer structure, giving OSB strength and stiffness in both directions. OSB is typically less expensive than plywood and utilizes smaller, fast-growing trees more efficiently. However, OSB absorbs water more readily than plywood and swells at the edges when wet, making proper weather protection during construction essential. Newer moisture-resistant OSB formulations have improved performance in humid conditions. Standard OSB panels measure 4 by 8 feet in thicknesses from 7/16 to 1-1/8 inches.
Usage Example
We used 7/16-inch OSB for the wall sheathing and 3/4-inch tongue-and-groove OSB for the subfloor throughout the new house.