OSB’s initial success is reminiscent of rock bands like Van Halen and Dire Straits: they all launched in the late 1970s and became immediate hits.
In the 1980s, North American OSB panel production went from about 750 million square feet to more than 7.5 billion square feet – a tenfold increase. By 2000, OSB had reached market-share parity with plywood. Today, most organizations estimate its market share to be at least 75percent.
Why has OSB become such a juggernaut in homebuilding? There are six main reasons:
Versatility – Unlike plywood, OSB can be engineered in special formulations for different types of climates and projects. Moreover, a layer of fire-resistant material can be added to OSB in the mill, which is how LP FlameBlock Fire-Rated OSB Sheathing is manufactured. This enables architects to design fire code-compliant wall assemblies that reduce dead load and wall thickness.
Price – The National Association of Certified Home Inspectors (NACHI) estimates that for a typical 2400-square foot home, OSB costs $700 less than plywood.
Consistency – Plywood usually tops out at seven plies, while a sheet of OSB is made from about 50 strand layers packed and compressed into the same thickness. That means that OSB panels don’t have the knotholes and core voids that are commonplace in plywood panels.
Longer lengths – OSB panels can be factory-manufactured in lengths up to 24 feet, while plywood is limited by tree size to the 8- to 10-foot range. OSB can also be purchased in 9-foot sheets, so builders can sheath a wall from the top plate to the bottom of the floor joists with single, vertical sheets that don’t leave horizontal seams.
Superior shear strength – Due to OSB’s thickness, its shear values are about twice those of plywood, which explains why it’s increasingly used for webs of I-joists.
Better for the environment – Making plywood requires hacking down big-diameter trees from old-growth forests, while OSB is made from small-diameter trees that can be sustainably farmed.
Homebuilders have used plywood for more than a century, but its market dominance peaked in the 1960s. Plywood simply can’t compete with OSB in the six key categories above, and its market share may soon slip into the single digits.