Information on Plywood

Plywood is commonly used for wall and roof sheathing.

Plywood is an engineered wood product made by gluing together thin slices of wood. Plywood panels are widely used in wood-frame construction, primarily for sheathing but also for exterior siding and interior paneling.

Construction

The grain direction of each slice, called a ply, is oriented at a 90-degree angle from the grain of adjacent slices. This arrangement makes plywood surprisingly strong. The slices are glued together under high temperature for optimal bonding.

Installation

Plywood allows for rapid installation because it comes in large sheets---typically 8 feet by 4 feet---and because its dimensions are exact. With accurately spaced framing, plywood can be quickly attached with almost no adjusting or trimming.

Uses

Plywood is highly advantageous as wall sheathing. Walls needs to be laterally braced; in the past, this was often accomplished with let-in diagonal bracing, which is somewhat time-consuming to install. Plywood can be nailed directly to studs without any diagonal bracing because the large size of the plywood sheet provides sufficient bracing. Plywood is also effective as roof sheathing and subflooring.

Strength

The strength of plywood as compared with oriented strand board and solid boards is a topic of ongoing debate. However, studies generally indicate that all three have their merits and demerits and that all three are perfectly adequate when properly installed.

References

• Ball State University: The Manufacturing of Plywood
• University of Massachusetts, Amherst: Choosing Between Oriented Strandboard and Plywood

Resources

• University of Arkansas: Veneer and Plywood