Structural Plywood Vs. Exterior Plywood

Exterior and structural plywood is more resistant to weather than interior laminates.

Plywood is a durable and economical alternative to solid wood. Its uses include anything from outside walls and structures to aircraft fuselages or fine finished interior cabinetry. Plywood is produced from various combinations of wood laminates and bonding materials. This creates types of plywood suitable for specific structural or general exterior applications.

Plywood Basics

Plywood commonly is sold in sheets that measure 4 feet by 8 feet. Plywood is made up of thin layers of wood glued together with bonding agents. The layers of wood are usually placed with the grain running in a different direction from the adjacent layer to add strength, particularly for exterior and structural applications. Plywood is graded on a scale of A,B,C, or D, with grade A representing the best finish.

Exterior Plywood

Exterior plywood is carried in large quantities by most home improvement stores. The glues that bond exterior plywood together are more moisture-resistant than those used for interior plywood. Exterior plywood usually has one side that is a grade "higher" than the other and is designated A-C, B-C, or C-D. Some decorative projects may require a higher grade.

Structural Plywood

Structural plywood is constructed with much less attention to appearance. The primary concern is strength and the ability to weather the elements. These types of plywood are used for bracing, walls where aesthetics are not a concern, forms for concrete, flooring and roofing.

References

• American Plywood Association (APA): Choose The Right Exposure Classification
• Inside Woodworking: Plywood
• APA The Engineered Wood Association: Plywood Library Articles