I had no idea that there were different types of plywood until I needed to build a treehouse for my daughter. I found out that we categorize plywood types by the kind of ply used which can then be broken down into further subcategories.
What is Plywood?
Plywood is an engineered wood from the manufactured boards family, which also includes particle board and oriented strand board (OSB). The types of wood species that are used in engineered plywood include ash, oak, birch, maple, cedar, spruce, and pine.Types of Plywood – The Home Depot
Types of Ply
As far as I understand, ply refers to the number of layers manufacturers use to create various degrees of thickness in the plywood.
There are three main different plywood types based on the number of layers. They are 3-ply, 5-ply, and multi-ply.
Each layer in a sheet of ply is known as a wood veneer. A veneer is a thin piece of wood that’s glued together to form a different number of plies.
Once the manufacturer glues the veneers together you end up with the finished product. Plywood.
3-Ply is the most common type of plywood. It’s the best type of plywood for indoor use because it has a more decorative look compared to the others. It’s the thinnest but it is still durable and strong.
5-Ply is stronger than 3-ply and has 5 layers instead of 3. They can be used for both outdoor and indoor projects.
Multi-Ply is the strongest plywood. It can exceed the standard number of layers to make up plywood of up to seven or more layers.
These type of ply are best suited for outdoor panels as they are the most durable and nature-proof plywood.
The higher the ply count, the stronger the plywood. The stronger the plywood the easier it is to use different types of screws and nails without worrying about splitting the wood ( I learned this the hard way).
The most common size for plywood sheets is 4 x 8 feet, followed by 5 x 5 feet. The Home Depot also carries pre-cut project panels that are available in different sizes that may vary by store.
These project panels help eliminate waste, cut costs, and are easier to transport than full-size panels.
The most common thickness of plywood is 1/2 inch but can range from 1/8 inch to 3 inches.
As far as plywood types and grades, there are 8 different styles and 4 different grades.
The plywood grading system uses the letters A, B, C, and D. A is the best and D is the lowest quality.
A, B, C and D. A is the best and most expensive, and D the least expensive.
Most woods use two letters. One letter designates the grade for the front of the board while the other represents the grade for the back.
A-grade plywood features a smooth, sanded surface without knots. Any wood defects have been repaired with synthetic filler, so the veneer can be painted, making it ideal for furniture or cabinet doors.
B-grade plywood also features a smooth, sanded surface, but may have more repaired defects up to 1-inch across.
C-grade is unsanded and may have several minor defects that will need to be repaired with knots up to 1 1/2 inches across, discoloration and sanding defects. C-grade plywood should be used when appearance is not important, such as on subfloors or garages.
D-grade is also unsanded with defects that have not been repaired and knot holes up to 2 1/2 inches across, discoloration and sanding defects.
You may also find ratings with two-letter classifications, such as BC. BC-grade is a mix grade plywood with one side graded a B, while the other side is graded a C.
Types of Plywood
Now that we know about ply and layers. Let’s talk about the various types of plywood and how each differs from the other in both materials and uses.
Softwood Plywood is plywood which has a face and back veneer of softwood as opposed to a hardwood such as Birch, Maple, Oak, etc. Softwood plywood panels are comprised of a core made from either softwood then faced and backed with a veneer of softwood and therefore are used for structural applications.Softwood Plywood | Anderson Plywood Sales
Soft Plywood is normally made from pine, redwood, or cedar and is used to build sheds, animal shelters, flooring, etc.
Hardwood Plywood is plywood which has a face and back veneer of hardwood as opposed to a softwood such as pine, cedar, spruce, etc.
Hardwood plywood is a great choice for furniture, cabinets, and many other projects due to its strength, stability, and convenience.
Normally, they are made of 3 to 7 layers of birch, maple, oak, or walnut wood.
Aircraft plywood is one of the highest grades of plywood that you can buy. The finished product is durable enough to withstand heat and moisture damage.
Exterior plywood has been waterproofed and is able to withstand extended exposure to inclement weather.
Lumber edge glued into a solid slab is considered Lumber Core. Lumber Core plywood is most often found in the construction of import panels, usually only 18mm thickness panels.Plywood Core Types | Hood Distribution
Marine plywood is manufactured from durable face and core veneers, with few defects so it performs longer in both humid and wet conditions and resists delaminating and fungal attack. Its construction is such that it can be used in environments where it is exposed to moisture for long periods.Plywood – Wikipedia
There are two types of overlaid plywood to consider. Medium density overlay (MDO) and high density overlay (HDO).
Structural plywood is also known as sheathing plywood. It’s the plywood you use to build up structures and frameworks. Eventually you cover it with other material for the finished product.
The main difference between structural and non-structural plywood is the type of glue used in the manufacturing of the boards. Plywood boards that meet structural standards have A-Bond types of glue bond.The Difference Between Structural And Non-Structural Plywood
The following are used as alternatives to plywood. They are NOT plywood but are used instead of plywood in some instances.
- Composite Woods
- Moisture-resistant Particleboard
How To Buy Plywood
You can go to your favorite hardware store and get help buying plywood. But, you can also get them online however, I always recommend going to a store to see the physical product.