Different Grades of Plywood: Understanding the Variations

What are the different grades of plywood?

Plywood is a versatile building material used in various construction and woodworking projects. It is made by gluing together thin layers of wood veneers, known as plies, to create a strong and durable sheet. However, not all plywood is created equal. Plywood comes in different grades, each with its own unique characteristics and intended uses. In this article, we will explore the different grades of plywood and help you understand the variations.

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Plywood Grades
by u/purduejay in woodworking

Table of Contents

1. Structural Plywood

Structural plywood, also known as sheathing plywood, is primarily used for structural applications where strength and stability are crucial. It is commonly used in roofing, flooring, and wall sheathing. This grade of plywood is manufactured with high-quality veneers and is designed to withstand heavy loads and resist bending or warping. Structural plywood is typically made with a moisture-resistant adhesive to enhance its durability.

1.1. Uses of Structural Plywood:

Application	Grade Recommendation
Roofing	CDX
Flooring	CDX or BC
Wall Sheathing	CDX or BC

2. Exterior Plywood

Exterior plywood, also known as exterior-grade plywood, is designed to withstand exposure to the elements. It is made with a waterproof adhesive and is suitable for outdoor applications where moisture resistance is essential. Exterior plywood is commonly used for exterior cladding, fences, sheds, and other outdoor structures. It is typically manufactured with a smooth surface finish, making it suitable for painting or staining.

2.1. Common Grades of Exterior Plywood:

ACX: This grade has a smooth sanded face and is suitable for applications where appearance is important.
BCX: This grade has a rougher face and is commonly used for structural applications where appearance is less important.
CDX: This grade has a rough face and is commonly used for sheathing and construction purposes.

3. Interior Plywood

Interior plywood, also known as interior-grade plywood, is designed for use in interior applications where moisture resistance is not a primary concern. It is commonly used for furniture, cabinets, paneling, and other indoor projects. Interior plywood is available in various grades, allowing you to choose the one that best suits your specific needs.

3.1. Common Grades of Interior Plywood:

A: This grade has a smooth, paintable surface and is suitable for applications where appearance is important.
B: This grade may have some minor defects but is still suitable for most interior applications.
C: This grade may have visible defects and is typically used for applications where the appearance is less important, such as shelving or subflooring.

4. Marine Plywood

Marine plywood is specifically designed for use in water-related applications, such as boat building or other projects exposed to high levels of moisture. It is made with waterproof adhesive and is constructed using high-quality veneers to ensure maximum durability and resistance to rotting or delamination. Marine plywood is typically more expensive than other grades due to its specialized construction.

4.1. Common Grades of Marine Plywood:

A-A: This grade has a high-quality face and back veneer, making it suitable for applications where appearance is important.
A-B: This grade has a high-quality face veneer and a slightly lower quality back veneer.
B-B: This grade has a lower quality face and back veneer but is still suitable for marine applications.

Understanding the different grades of plywood is essential to ensure you select the right type for your specific project. Whether you need structural strength, moisture resistance, or a smooth finish, there is a plywood grade available to meet your requirements. Consider the intended use, appearance, and budget when choosing the appropriate grade of plywood for your next construction or woodworking endeavor.