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OSB vs. Plywood
By Nick Gromicko and Rob London
Oriented stand board (OSB) and plywood are wood structural panels made by
compressing and gluing pieces of wood together. While OSB and plywood appear
similar and are generally interchangeable, the different ways that each
material is manufactured contribute to each having its own unique strengths
What are they, and how are they made?
OSB is manufactured from heat-cured adhesives and rectangularly shaped wood
strands that are arranged in cross-oriented layers. Produced in large,
continuous mats, OSB is a solid-panel product of consistent quality with few
voids or gaps. The finished product is an engineered wood panel that shares
many of the strength and performance characteristics of plywood.
Plywood is made from thin sheets of veneer (layers of wood that are peeled
from a spinning log) that are cross-laminated and glued together with a hot
press. Throughout the thickness of the panel, the grain of each layer is
positioned perpendicular to the adjacent layer. The finished product is made
from an odd number of layers so that a balance is maintained around its
central access. Since it is made from whole layers of logs rather than small
strands, plywood has a more consistent and less rough appearance than OSB.
A few facts about OSB and plywood:
While OSB developed fairly recently, it became more popular than plywood
in North America by 2000. Today, nearly twice as much OSB as plywood is
produced in North America.
Outside of North America, OSB is not commonly used in construction. In
2005, the combined production of OSB in Europe and Latin America was just
3.5 billion square feet – less than seven times as much as was produced in
North America that year.
While both products are made from different materials, and some builders
strongly prefer one or the other, OSB and plywood are both manufactured
according to the same performance standards.
OSB can be made from narrower, faster growing trees than plywood.
In favor of OSB:
OSB can be manufactured into panels that are larger than plywood.
OSB is more uniform, so there are fewer soft spots, such as those that
can occur in plywood.
OSB is less expensive than plywood. To build a typical 2,400-square foot
home, OSB may cost $700 less than plywood.
OSB is considered by many to be a “green” building material because it
can be made from smaller-diameter trees, such as poplars, that are often
farmed. Plywood production, by contrast, requires larger-diameter trees from
In favor of plywood:
While plywood and OSB both off-gas formaldehyde, OSB off-gasses more of
the carcinogenic gas. Plywood, OSB, and other engineered wood products that
contain glue can be stored outdoors for several weeks before construction so
that much of the dangerous gasses are vented safely into the outdoors.
OSB weighs more than plywood. One 23/32-inch 4'x 8' plywood piece weighs
approximately 67 pounds, while a piece of OSB of the same
weighs approximately 78 pounds. The increased weight of OSB means that it is
harder to install and it will put more stress on the house.
Compared to plywood, OSB swells more when it comes into contact with
water, especially at panel edges. According to George Pacific, a
manufacturer of OSB and plywood, swell is generally greater in OSB than in
plywood due to the release of compaction stress in OSB created during the
pressing of wood chips into panels. Swollen plywood will return to its
nominal thickness as the wood dries, while OSB will remain permanently
swollen, to some degree. Swelling is a nuisance because it can uplift
whatever materials lie above, such as tile or carpet.
Plywood floors are stiffer than OSB floors by a factor of approximately
10%. As a result, OSB floors are more likely to:
squeak due to floor movement;
cause hard floor surfaces to crack (such as tile); and
result in soft, spongy floors.
Nails and screws are more likely to remain in place more firmly in
plywood than in OSB.
OSB retains water longer than plywood does, which makes decay more
likely in OSB than in plywood. Of course, tree species plays a large role in
this determination. OSB made from aspen or poplar is relatively susceptible
to decay. In one of the biggest consumer class-action lawsuits ever,
Louisiana-Pacific (LP), a building materials manufacturer, was forced to pay
$375 million to 75,000 homeowners who complained of decaying OSB in their
In summary, OSB and plywood, while used for the same purposes, perform