Types of Plywood

Picture stepping into a new project—whether building a sturdy bookshelf, crafting custom cabinets, or creating structural supports for a home addition. Plywood’s unique composition makes it a go-to material for countless DIY and construction tasks. Its layered structure and range of grades, sizes, and finishes ensure you can find the perfect match for both hidden supports and visible features. Understanding how plywood is classified helps you choose confidently and achieve exceptional results.

1. What is Plywood?

Plywood belongs to the family of engineered wood products, which also includes materials like particle board and oriented strand board (OSB). It’s made by peeling thin veneers from debarked wood logs. These layers, or “plies,” are glued together with alternating grain patterns, creating a balanced, cross-grain construction. This structure reduces the risk of warping or cracking caused by moisture changes, providing a stable, durable material at a reasonable cost.

In construction, plywood often appears in subfloors, roofing underlayment, and wall sheathing—places hidden from view but vital for a building’s integrity. It’s also commonly used as the foundation beneath hardwood, tile, or carpet floors, and as a support behind other finish materials.

For more decorative projects, stainable and paintable plywood offers a smooth surface suited for cabinetry, furniture, and shelving. Outside the home, plywood can serve as fencing, scaffolding, storage sheds, and even packaging or shipping containers.

2. Common Types of Plywood

Several plywood types cater to different needs:

Sanded Plywood

Sanded plywood has top and bottom surfaces sanded smooth. It’s often chosen when the wood will remain visible, making it an excellent fit for cabinetry, shelving, and interior paneling.

Hardwood Plywood

Made from hardwoods like birch, oak, or maple, hardwood plywood offers excellent strength and stability. Heavier and more robust than standard panels, it’s ideal for furniture frames or projects that need to bear substantial weight.

Plywood Sheathing

Plywood sheathing, or structural plywood, is strong, affordable, and built for permanent construction use—like wall, floor, and roof framing. It’s usually left unfinished and later covered by other materials, making it perfect for hidden support structures.

Project Panels

Project plywood panels come pre-cut in convenient sizes, ready for smaller DIY endeavors. They’re great when measurements are known upfront, making them a favorite of beginners and anyone looking to save time.

Markerboard

Some plywood panels feature a coated surface suited for dry-erase markers, providing a writable and reusable workspace—an ideal choice for craft tables, workshops, or creative studios.

3. Layers and Plies

A “ply” is a single veneer layer. More plies generally mean a thicker, sturdier board. Plywood commonly comes as 3-ply, 5-ply, or multi-ply (seven or more layers).

• 3-Ply: About 2–3 mm thick, often used indoors where appearance matters.
• 5-Ply: Around 4 mm thick, suitable indoors and outdoors. Steer clear of using it as primary framing in large, load-bearing structures.
• Multi-Ply: Seven or more layers, providing exceptional strength for structural tasks like roofing and framing.

Tip: Higher ply counts generally mean more strength, even at similar thicknesses.

4. Ratings, Grades, and Sizes

When choosing plywood, consider its rating, grade, and size:

Ratings

• Exterior: Designed to handle long-term moisture exposure.
• Exposure 1: Withstands weather exposure during construction but not recommended for prolonged wet conditions post-build.
• Exposure 2: Tolerates occasional moisture but best used indoors.
• Interior: Not moisture-resistant; keep these panels dry and indoors.
• Structural 1: Specific seismic rating for earthquake-resistant construction.

Grades

Plywood is graded A, B, C, or D, indicating surface quality:

• A-Grade: Smooth, sanded, defect-free (or repaired) surface that can be painted. Perfect for high-quality furniture or cabinetry.
• B-Grade: Nearly as smooth as A, but may have a few more small repairs.
• C-Grade: Unsanded, with noticeable but fixable defects. Suitable for subfloors and less visible structural work.
• D-Grade: Lowest grade, unsanded, and may contain unrepaired defects. Good when appearance isn’t a priority.

You might see two-letter combinations, like BC, indicating one side B-grade, the other C-grade.

Common Sizes

Typical full sheets measure 4 x 8 feet or 5 x 5 feet, with project panels available in more manageable sizes. The standard thickness is often 1/2 inch, but you can find options from 1/8 inch to 3/4 inch.

5. Other Engineered Wood Alternatives

Other engineered boards, sometimes called “plywood” though made differently, can also suit your project’s needs:

• Stainable plywood: Pre-sanded for a natural, finished look once stained.
• Paintable plywood: Accepts paint or laminate easily for custom décor.
• Pressure-Treated: Resists weather, decay, and insects.
• Tongue-and-Groove: Edges fit together snugly, ideal for creating strong, seamless joints.

Final Thoughts

Choosing the right plywood type means weighing appearance, strength, environment, and budget. Consider how it will be used—hidden structural support or as a visible design feature—and select based on grades, ratings, and plies. For smaller projects or unique finishes, pre-cut panels or engineered alternatives can save you time and effort.