If you plan to buy plywood for the first time, the wide range of options can feel overwhelming. Many home projects require a specific plywood type, so you need to understand your choices before you make a decision.
This guide covers the most common types of plywood and shows you how to choose the right one for your project, whether you build a shed, craft furniture, or renovate your home. You’ll also find insights from This Old House experts Norm Abram and Tom Silva.
What Is Plywood?
Plywood is a composite material made from thin layers of wood veneer, called plies, glued together. Each layer’s grain runs perpendicular to the layers on either side, giving plywood its strength and stability and making it resistant to warping, twisting, and shrinking. The number of plies can vary, but generally, more layers result in stronger and more stable plywood.
The Plywood Manufacturing Process
Producing plywood starts with selecting logs that then get peeled or sliced into thin veneers. These veneers are dried, sorted, and layered with adhesive between each ply. The layers are pressed together under high pressure and heat, creating a strong bond. The outer layers, known as the face and back, are typically of higher quality than the inner ones.
Each step in the plywood manufacturing process is crucial to ensure the end product’s strength and durability. The choice of logs, the precision in slicing veneers, and the adhesive used all contribute to the plywood’s final quality. This meticulous process ensures that the plywood can withstand various environmental conditions and hold up over time.
Core Types of Plywood
The core of each type of plywood is the biggest factor that makes it ideal for some projects and not others, so it’s important to choose the right one for your specific needs.
Veneer Core Plywood
Veneer core plywood is the most common type, consisting entirely of wood veneers. It’s known for its strength and lightweight nature, making it ideal for structural applications and furniture making. This type of plywood offers excellent screw-holding capabilities and is less prone to warping than solid wood.
The dominance of veneer core plywood in the market speaks to its effectiveness and reliability. Builders and craftspeople often opt for this type due to its balance of strength, ease of manipulation, and resistance to common wood issues. It provides a robust foundation for various applications, from flooring to cabinetry.
MDF Core Plywood
Medium-density fiberboard (MDF) core plywood features outer layers of wood veneer with a core made of MDF. This construction results in a stable and uniform product with a consistent thickness. MDF core plywood is often used for cabinet doors and other applications where a smooth, flat surface is crucial.
MDF core plywood is prized for its smooth finish, making it ideal for painted surfaces or detailed work. Its uniform thickness makes it easy to work with, providing a reliable base for intricate designs and precision crafting. This makes it a go-to material for fine furniture and high-end cabinetry.
This Old House master carpenter Norm Abram highlights a key advantage of MDF over plywood for cabinetry: “With plywood, you have to follow the grain, so you wind up with lots of small pieces of scrap you can’t really use. Whereas with MDF, it’s nondirectional, so you get more efficient use of the sheet.”
Abram also adds that MDF simplifies edge treatment. “With plywood, every time you expose an edge, you’ve got to find a way to cover it, but with MDF, the edge is treated just like a solid piece of wood,” he says.
Lumber Core Plywood
Lumber core plywood consists of a core made from solid wood strips sandwiched between veneer layers. This type is exceptionally strong and resistant to warping, making it an excellent choice for long shelves and tabletops where minimal deflection is desired.
The solid wood strips within lumber core plywood provide unparalleled strength, making it ideal for heavy-duty applications. Whether building expansive tabletops or long shelving units, this plywood type ensures minimal flex and excellent load-bearing capabilities. Its durability makes it a favorite among builders requiring sturdy and long-lasting materials.
Plywood Grades and Their Applications
Plywood is graded based on the quality of its face and back veneers. The grading system offers a useful guideline for builders and DIY enthusiasts, ensuring they choose the right quality for their needs.
Grade A Plywood
Grade A plywood has a smooth, sanded surface with minimal defects. It’s suitable for high-end cabinetry, furniture, and other visible applications where appearance is crucial. This grade can be painted or stained for a finished look.
Choosing Grade A plywood guarantees an excellent finish, making it perfect for visible areas. Its smooth surface allows for high-quality paint or stain applications, ensuring a polished and sophisticated end result. This grade is often used in projects where aesthetics are a top priority.
Grade B Plywood
Grade B plywood has a solid surface with some minor repairs and small knots. It’s less expensive than Grade A and is often used for cabinet interiors or as a substrate for thin veneers.
While Grade B plywood may not boast the flawless surface of Grade A, it still offers a solid and reliable finish. This makes it a more cost-effective choice for internal applications or areas covered by another material. The cost-to-strength ratio makes it a practical choice for many projects.
Grade C Plywood
Grade C plywood is unsanded and may have visible defects like knots and patches. It’s typically used for structural applications where appearance is unimportant, such as subflooring or wall sheathing.
In structural applications, Grade C plywood is valued for its strength rather than its appearance. Its visible defects do not affect its functionality, making it a cost-effective solution for internal frameworks and support structures where aesthetics are secondary.
Grade D Plywood
Grade D is the lowest quality, with larger knots and more visible defects. It’s used primarily for structural purposes in areas that will be completely hidden from view.
Despite its visible imperfections, Grade D plywood provides necessary structural support at a lower cost. It is suitable for hidden areas where function is more critical than form, such as substructures and behind-the-scenes frameworks.
Pro Tip: Match the different plywood grades to the purpose on every job, according to Tom Silva. For hidden wood such as sheathing or subflooring, he recommends using cheaper CDX ply, which has a C-grade face, D-grade back, and glue rated for Exposure 1. When looks count, as in cabinetwork, consider A-grade ply, which has fewer knots and patches.
Plywood Sizes and Thicknesses
Plywood comes in various sizes and thicknesses to suit different project needs. Understanding these dimensions helps in planning and executing projects with precision. The most common plywood sheet sizes are:
- 4 feet by 4 feet
- 4 feet by 8 feet
- 5 feet by 5 feet
Common Plywood Thicknesses
Plywood thickness ranges from 1/8 inch to over 1½ inches. The most commonly available thicknesses in home improvement stores are ½ inch, ¾ inch, and 1 inch.
These standard sizes and thicknesses allow for flexibility in project design. Whether for small-scale crafts or large construction projects, the range of dimensions ensures the availability of suitable plywood options.
Specialty Plywood Types
Certain applications require plywood with specific properties. Here are some specialty types designed to meet unique requirements.
Exterior Sheathing Plywood
This type is designed to withstand exposure to moisture and is often used in construction for exterior walls and roofing. It’s typically rated CDX, where “C” is the face grade, “D” is the back grade, and “X” indicates it’s suitable for exterior use.
Exterior sheathing plywood is formulated to resist environmental challenges. Its durability against moisture makes it an essential material for constructing the outer layers of buildings, ensuring that the internal structures remain protected from the elements.
When installing exterior sheathing plywood, Abram and Silva recommend leaving a ¼-inch space between wall, roof, and subfloor panels to allow for expansion and contraction. Always lay plywood so its long dimension runs perpendicular to joists, rafters, or studs, and stagger joints so four corners never meet in one spot, which weakens overall strength. For walls, use ½-inch plywood over studs 16 inches on center.
Subfloor Plywood
Subfloor plywood is thicker and more water-resistant than standard plywood. It often features tongue-and-groove edges to create a tight, squeak-free floor surface.
The structural integrity required for flooring requires robust and moisture-resistant subfloor plywood. Its tongue-and-groove design ensures a stable and even surface, minimizing movement and noise, which is crucial for comfortable, long-lasting flooring.
Tom Silva recommends using only 4-by-8-foot sheets of ¾-inch tongue-and-groove plywood for subflooring: “Pieces of this size create fewer seams; the fewer seams there are, the more secure the floor,” said Silva. “The interlocking joints are stronger, and thick boards are less susceptible to splitting between joists.”
Silva also advises running the long side of the plywood perpendicular to the joists for maximum strength.
Marine Plywood
Marine plywood is made with waterproof glue and high-quality veneers to resist delamination and rot in wet environments. It’s used in boatbuilding and outdoor furniture.
Marine plywood’s composition makes it uniquely suited for environments with high moisture exposure. Its resistance to water damage ensures longevity and reliability, whether used in constructing boats or crafting durable outdoor furniture.
Aircraft Plywood
Aircraft plywood is high-strength, lightweight, and made with special adhesives and select veneers. It’s used in the aviation industry and for high-performance applications.
In demanding applications where performance is critical, aircraft plywood provides the necessary strength without adding excessive weight. Its high-quality construction ensures it meets stringent industry standards, making it ideal for aviation and other specialized uses.
Pros and Cons of Using Plywood
Plywood offers many advantages, including strength, stability, and versatility. However, it also has some limitations, such as visible edges and the potential for delamination if exposed to excessive moisture.
Advantages of Plywood
Plywood’s primary benefits include its strength and resistance to warping. Its layered construction provides a robust material that can handle significant weight and stress. Additionally, it’s versatile enough to be good for a wide range of applications, from structural to decorative. Plywood is generally more stable than solid wood, as its multiple layers counteract wood’s natural tendency to shrink and expand.
Drawbacks of Plywood
Despite its advantages, you might have to finish plywood’s edges. The potential for delamination under excessive moisture exposure is another concern, requiring careful selection and treatment for outdoor or high-moisture environments. Another limitation can be the variability in quality between different grades, which means selecting the right type and grade is crucial.
How To Buy Plywood: Tips and Tricks
When purchasing plywood, inspect sheets carefully for defects, especially if the surface will be visible. Look for flat, undamaged sheets and check the edges for gaps or voids. For projects requiring a finished look, consider higher-grade plywood or specialty products like ApplePly, which offers an attractive edge grain for furniture and drawer construction.
Inspecting Plywood
Careful examination of plywood sheets ensures that the material is fit for purpose. Check for any signs of damage, warping, or inconsistencies in the veneer. Pay particular attention to the edges to ensure there are no gaps that could compromise its structural integrity. Also, inspect the surface for any blemishes or defects that could impact the project’s final appearance.
Purchase Considerations
Consider the plywood’s intended use and select a grade that matches your project’s needs. For visible surfaces, higher-grade plywood offers fewer imperfections and a better finish. For structural uses, lower grades might be sufficient and more cost-effective. Don’t forget to calculate the amount required accurately to avoid shortages or excessive wastage.
Best Plywood for Specific Applications
- Cabinetry: Grade A or B veneer core or MDF core plywood
- Subflooring: CDX or tongue-and-groove plywood
- Outdoor projects: Exterior-rated or marine plywood
- Furniture: Hardwood plywood
Plywood Alternatives and When To Use Them
While plywood is versatile, other engineered wood products like oriented strand board (OSB), medium-density fiberboard (MDF), and particleboard may be more suitable for certain applications. These alternatives can offer cost savings or specific properties that plywood may lack.
Oriented Strand Board (OSB)
OSB is a low-cost alternative to plywood, made from strands of wood mixed with adhesives. It offers good strength for structural applications, particularly in subflooring and wall sheathing. However, OSB is less resistant to moisture compared to some grades of plywood.
Medium-Density Fiberboard (MDF)
MDF is known for its smooth surface and consistent thickness, making it an excellent choice for painted surfaces and detailed work. It is heavier and denser than plywood but lacks the inherent structural strength, making it less suitable for load-bearing applications.
Particleboard
Particleboard is another cost-effective alternative, often used in flat-pack furniture and cabinetry. While it is smooth and easy to work with, it lacks the durability and strength of plywood, making it suitable only for non-load-bearing applications.
Our Conclusion
Plywood offers a balance of strength, stability, and affordability. By understanding the different types, grades, and applications of plywood, you can make informed decisions for your projects.
When selecting plywood, consider factors such as moisture exposure, load-bearing requirements, and aesthetic needs. With the knowledge gained from this guide, you’ll be well-equipped to choose the perfect plywood for your next undertaking.
