What Is OSB Sheathing?

OSB is used to sheath a building exterior in preparation for siding.

After a home under construction is framed, the next step is enclosing that frame in sheathing. OSB is a common building material used for sheathing the sides and roof of a home.

OSB

OSB, or oriented strand board, is a wood product made from resin and small chips of wood called strands and sold in 4-foot by 8-foot sheets, 1/4-inch and thicker. The common thickness for sheathing a home is 1/2 inch.

Sheathing

Roofs and the sides of houses are covered with sheathing in the form of OSB or plywood. The sheathing adds strength and stability to the framing and is the substrate to which roofing materials and siding are attached.

Cost

OSB costs less than plywood and is suitable for most building construction in the form of roof and side sheathing. By comparison, a typical sheet of 1/2-inch plywood sheathing at a home center or lumberyard would be nearly double the cost of a comparable thickness of OSB.

References

• Georgia-Pacific Corporation: Oriented Strand Board
• International Building Code 2009: Floor and Roof Sheathing 2304.7
• International Building Code 2009: Particleboard shear walls 2306.5
• International Building Code 2009: Wood structural panel shear walls 2306.3

Resources

• Small House Building: Structural Wall Sheathing