Different Types of Exterior Plywood Explained

Exterior plywood is where the wood is bound together using water-resistant glues. Because of this, it is best suited for outdoor construction. It is the most common bonding type of plywood available.

Exterior plywood can be divided into several types based on the materials and grades. Given the scope of this article, it is impossible to list every single type, but we will explain how the types are determined and what kinds of things home owners should look for when shopping for exterior plywood.

Understanding Plywood

Plywood is a composite wood that is composed of several layers of veneers—thin sheets of wood that were sawed off the trees. The veneers are layered one atop of another and glued together. If the plywood is put together using water-resistant glue, it is considered to be exterior plywood. Such glue will resist rain, snow, and humidity, but if the home owner lives in an area where weather conditions are usually harsh, he or she may want to consider getting a stronger type. Plywood gives home owners more flexibility, allowing them to create designs that would not be possible with ordinary wood.

Exterior Plywood Grading

When purchasing exterior plywood, one of the first things the home owners look for is grade. Like other types, exterior plywood is classified based on appearance using letter grading system, A through D, with each letter representing the quality of the wood. As with a school grading system, grade A represents the best, least-damaged plywood, while grade D represents the most damaged and worn pieces. Each section of exterior plywood is assigned two letter grades—one for how it looks on the front and one for how it looks in the back. Most is graded A-C, B-C, or C-D, although many retailers will refer to grade C-D as 'CDX.' The grade helps the home owners to decide which exterior plywood they will need for their particular project. Higher grade pieces work best for decorative projects, while lower grade plywood works best for the more utilitarian purposes.

Exterior Plywood Materials

Another important thing home owners need to consider is what kind of materials make up the plywood's veneers. This determines how well it will endure weather and how it will look. Plywood can be made of several different materials arranged in various combinations.

Pine

This is the most basic underlying material in exterior plywood.

Spruce

This material remains strong no matter how thinly it is sliced for plywood.

Mahogany

Mahogany tends to be free of any voids and pockets within its grains. It is best used for cabinets and furniture.

Douglas fir

Douglas fir is sturdier than many others, which makes it ideal for any structures designed to withstand high loads.

Birch

This is the strongest material out of them all, but since it is vulnerable to changes in temperature, it must be surrounded by other veneers in order to be of any use.

Oak

In addition to being tough, this material is highly resistant to insects and fungi infection, which makes it an important component of any exterior plywood.

Maple

This is largely a decorative material that is included in the exterior plywood to give it a nice-looking texture.