The many types and grades of plywood.
The invention of plywood can be one of the most signifficant development in the technology of
woodworking. This is one form of a wood product that makes it very useful and versatile to the
Plywood is a flat panel built up of sheets of veneer called plies, put together under extreme pressure
by glue to create a panel with an adhesive bond between the plies. Plywood can be made from either
hardwoods or softwoods.The outside plies are are called faces or face and back plies; the inner plies
are called centers or cores; and the plies with the grain perpendicular or a right angle to that of the
face are called crossbands. Crossbands gives the panel strength and keep the grain of the panels
from running all in the same direction.
With having grain running in both directions the plywood can have equal strength in its width and
length. Plywood will also be less prone to splitting, checking, and warping and its dimensional
quality will have a high rating also.
In general there are two classes of plywood available,(a) Constuction and industrial, (b) Hardwood and
decorative. The first type (a) has traditionally been made from softwoods such as Southern Pine, white
fir, western hemlock, douglas-fir and redwood. A large number of hardwood qualify under the current
standard for use also, but the standard for hardwood and decorative plywood covers certain decorative
softwood species for nonconstruction use only.
Most of the constuction and industrial plwood that is used in the United States is produced domestically
with some of the manufacturers exporting some materials. The majority of constuction and industrial
plywood is used where stiffness and strength and construction codes are more important than the
appearance of the plywood. There are some grades of this plywood that are made with the face of the
plywood selected just for the appearance and generally used with clear natural finishes or with stain
Hardwood and decorative plywood can be made of many different species, both in the United States
and abroad. United States imports a large amount of panels that are used in this country. Hardwood
plywood is use in applications such as decorative wall panels and in the cabinet and furniture industry
where appearance is a important factor.
These are some examples of various types of panels but the pictures of the panels does not give the
actual appearance justice. The best way to view the various panels is to go to your local home
improvement store or lumber yard to see first hand the differences in each of these panels.
Oriented Strandboard also known as OSB can be used for roof sheathing, underlayment, subfloors,
single-layer floors, exterior siding, and wall sheathing. These panels are free of knotholes and will
securely hold screws and nails. Some of the grades available are siding, sheathing, and single floor with
sizes available in 4' x 8' sheets and thickness that range from 3/8' and up.
Particleboard is a hard and dense composition board that has small particles of wood that has
been glued together with various types of adhesive under extreme pressure and heat. Mainly used in
non-structual constuction such as closets, and because it will not warp it makes a good underlayment
also. It does have a tenancy to swell if it gets wet
Hardboardis made from chips of wood that has been machined down to wood fibers and then
adhered together into thin panels under heat and pressure. These panels are also dense, strong,
grainless, and very dry. Some of the uses of these panels are perforated boards, interior paneling,
cabinets, toys and much more. Warping can occur if it is used in areas where high temperature
and humidity exists.
Plywood, Back to Lumber