Types of Plywood Explained: What Builders Won't Tell You

Plywood's basic structure comes from multiple thin sheets of wood veneer (plies) glued together. The magic happens in how these layers work together. Each sheet runs at right angles to the ones next to it, creating what we call cross-grain construction. This clever design gives plywood strength and stability that regular lumber just can't match.

A plywood panel usually has 3 to 13 layers, based on how thick it needs to be. Manufacturers use an odd number of plies to keep things balanced and reduce warping when the wood is under stress. The outer layers - face ply on top and back ply on bottom - sandwich several core plies, all held together with industrial-strength glue.

The outer plies do more than just look good. Face plies use better quality wood, which matters a lot in furniture-grade plywood. Back plies don't need to be as pretty since they're usually hidden. The core plies are the real workhorses, giving plywood its famous strength and stability.

This cross-grain pattern isn't just clever manufacturing - it's a game-changer that gives plywood some big advantages:

• Stays stable when temperatures change
• Resists cracking and splitting at the edges
• Spreads stress evenly across the whole panel
• Offers equal strength in every direction, unlike regular wood

Heat and pressure bond these layers so strongly that the glue joints are often tougher than the wood itself. This means plywood keeps its shape even when moisture levels change.

How plywood stands apart from solid wood

Plywood and solid wood are quite different, which explains why builders often reach for plywood first. Plywood stays more stable - it won't shrink or swell much when humidity changes, but solid wood sure will.

Plywood also makes better use of trees. Regular lumber wastes a lot of wood during cutting, but plywood's rotary cutting method uses most of the log. This smart manufacturing keeps costs down and saves trees.

Strength works differently in these materials too. Solid wood is tough along its grain but weak across it. Plywood spreads its strength evenly in all directions thanks to its criss-crossed layers. This makes it perfect for jobs that need strength in every direction, like subfloors and structural panels.

Plywood also handles nails and screws better near its edges, where solid wood tends to split. Those alternating grain directions stop cracks from spreading. You can also get plywood in bigger sheets than solid wood, which speeds up work on large surfaces.

Solid wood still wins on looks though. Even fancy plywood rarely matches solid wood's natural beauty, especially in fine furniture. But decorative plywood with nice veneer can work well for many projects.

Core types that affect quality and price

The core construction of plywood makes a big difference in how it performs and what it costs. Each type has its own strengths and limits that can make or break your project.

Veneer Core is what most people think of as regular plywood. It's all wood veneers crossed over each other. This makes a strong, lightweight panel that holds screws well. It's great for shelves and structural work because it resists bending. The downside? Small gaps in the inner layers might show through fine finishes.

MDF Core puts wood veneer faces over a medium-density fiberboard center. These panels are super flat and smooth. They're perfect for cabinet doors where you need a flawless finish. The trade-off is weight - each 3/4" panel weighs about 100 pounds. They also don't hold screws as well as veneer core.

Particleboard Core costs less than other options. Like MDF core, it gives you a smooth surface that's great for laminating. But it comes with limits: it's heavy at 100 pounds per 3/4" panel, doesn't hold screws well, and hates moisture.

Combination Core takes the best features of different materials. It uses veneer core inside with MDF layers under the face veneers. This gives you strength and screw-holding power plus a smooth surface. It's a smart choice when you need both structural strength and a nice finish.

Lumber Core uses strips of wood glued edge-to-edge between thin veneer layers. This creates a super strong, stiff panel that holds screws like a champ. It's perfect for big shelves and tables that can't sag. Just know that it only comes in thick panels and costs more.

These core differences really matter. The core type often matters more than face veneer quality or thickness when picking plywood. Each type balances weight, strength, surface quality, and moisture resistance differently.

Think about what you need most - screw holding, smooth surfaces, weight limits, or moisture protection. Pick the core type that matches your priorities instead of just grabbing the cheapest option.

Major Types of Plywood and Their Hidden Properties

Softwood plywood will give you impressive strength and versatility, despite its name. We sourced it from coniferous trees like spruce, pine, and fir (SPF), and these panels are construction industry workhorses. The "soft" label comes from the wood species used, not the panel's actual hardness or durability.

Softwood plywood packs excellent strength for structural uses, which surprises many people. These panels can become "as hard as concrete" with specialized coating systems that boost their durability. This makes them valuable for shuttering strands and construction where strength matters most.

Most softwood plywood comes with moisture-resistant glue like phenol resin adhesive, which makes them exterior-grade panels. This hidden feature means they resist weather better than expected. You can use them in many ways:

• Construction work and building projects
• Ventilation panels and packaging
• Flooring, walls, and roofing
• Machinery and vehicle parts
• Fencing and general structural support

The strength-to-weight ratio of softwood plywood stands out. These panels can handle heavy loads while staying light enough to work with easily. That's why builders use them so much in construction framing and sheathing.

Hardwood plywood: Beauty with caveats

Hardwood plywood deserves its reputation for stunning looks and superior durability. It's made with veneers from deciduous trees like oak, maple, birch, cherry, and walnut. These panels show off wood's natural beauty while performing remarkably well.

Quality hardwood plywood's strength often surprises builders. The Decorative Plywood Association says these panels can outperform steel in static bending strength. This exceptional structural integrity makes them great for demanding jobs beyond just looks.

You should know some important things about hardwood plywood. It costs more than softwood types because of its beauty and strength. The panels can also suffer moisture damage without proper sealing and finishing, which people sometimes forget when praising their looks.

Hardwood plywood works great in many applications:

• Furniture construction (cabinets, shelves, tables)
• Cabinetry for kitchens and bathrooms
• Interior doors and decorative paneling
• Trim work including baseboards and crown molding
• Musical instruments and sporting equipment

The biggest difference between structural and non-structural plywood might be the most important thing to know when picking plywood. These two types serve completely different purposes based on how they're engineered, even though they look similar.

Adhesive technology makes the main difference. Structural plywood uses A-bond or B-bond glues made with phenol formaldehyde resin or melamine-urea formaldehyde combinations. These adhesives create bonds that handle environmental challenges like temperature changes and moisture without weakening the panel's structure.

Non-structural plywood uses C-bond or D-bond glues made with urea formaldehyde resin. These adhesives break down faster in humidity and temperature changes, so non-structural types won't work for load-bearing jobs or outdoor use.

You should never use non-structural plywood where you just need structural support—no matter how thick it is or how it looks. This applies to important areas like:

• Flooring and roof sheathing
• Wall construction and bracing
• Support beams and hoarding
• Exterior applications exposed to weather

Plywood grades follow a clear A to D system that reviews the quality of face and back veneers. Each letter shows a specific quality level, and the differences between grades are significant.

Grade A gives you premium quality with smooth, sanded surfaces that have no knots or defects. This top grade delivers a flawless finish that works great for staining or painting. You'll see Grade A plywood in luxury cabinetry, furniture, and projects where looks matter most.

Grade B comes in just below top quality but works well for many visible uses. Small knots up to 1 inch wide and slight color changes might show up. These minor flaws don't stop Grade B plywood from taking paint and finish nicely.

Grade C shows more obvious flaws, with knots up to 1.5 inches wide and some patches or repairs. This grade focuses on strength rather than looks. It works great for subflooring, roofing, and wall sheathing where appearance takes a back seat.

Grade D has the most defects, including knots and holes up to 2.5 inches wide plus plenty of patches and repairs. This least expensive grade works best in construction where other materials will cover the plywood.

The truth about combination grades