Synopsis: Either plywood or oriented-strand board (OSB) provides the structural skin on most houses today. Used for floors, walls, and roofs, these sheathing products are ubiquitous, but are they created equal? This article details exactly how the two products compare in strength, water resistance, and even environmental impact. A sidebar offers tips for storing and installing these products to avoid problems.

Like the old latex- versus oil-paint debate, people hold strong feelings about oriented strand board (OSB) and plywood. Because there seems to be some truth on each side of the argument, it’s not easy to figure out which type of structural panel you should be using.

From a cost-saving perspective, the appeal of OSB is easy to understand. Sheathing a 2500-sq.-ft. house with OSB can save about $900 compared to the cost of plywood sheathing. OSB advocates also point out that these panels are more uniform than plywood and that OSB has a higher “green building” value because it can be manufactured from lower-grade logs rather than veneer-grade timber. Many wood species can be used for OSB, not just soft woods, as is the case with plywood sheathing. Plywood advocates counter that it’s tough to argue with a 50-year durability record and claim that plywood is a stronger panel that holds up better to water.

Despite the strong opinions, contractors and homeowners have been adopting OSB steadily since its commercial introduction around 1980. Within 10 years, it had snagged one-third of the market from plywood, and by 1999, OSB production had surpassed plywood. Mills now produce about 1.5 times more OSB than plywood, and APA – The Engineered Wood Association forecasts that OSB will continue to gain market share.

Rocky starts for plywood and OSB

Carpenters were quick to find flaws in both plywood and OSB when they were introduced to the…