It may be hard to believe, but plywood comes in a variety of types with different uses, grades, sizes, and ratings. The choices can appear unlimited! Whether you are new to DIY or an experienced woodworker, it’s crucial to know which plywood type is ideal for your project.
Plywood
Plywood, comprised of thin veneer sheets sourced from various softwoods and hardwoods, is an engineered wood. It is widely favored for construction and DIY endeavors due to its affordability, strength, and durability.
Plywood has been utilized for various projects, such as a faux shiplap wall, a giant pegboard, benches, and cabinetry. It is an exceptionally adaptable material that is suitable for numerous indoor projects.
Many individuals believe that plywood projects will appear cheap and unappealing due to the material itself. However, this perception is incorrect. Although specific types of plywood are more suitable for certain projects, there are various available products that can enhance the appearance of plywood projects by smoothing rough edges and improving their overall look.
Understanding ply
Plywood’s ply denotes the thickness of the board, which is determined by the number of layers it comprises. The thickness required for a project depends on the desired strength, thus allowing for the involvement of smaller pieces as an alternative. To achieve the desired number of plies, each layer, referred to as a wood veneer, is bonded to another layer through gluing.
When considering different types of boards, it is important to carefully assess each one because veneers themselves can have varying thicknesses. Although two boards may have the same number of plies, the thickness of the final board may differ depending on the place of purchase.
Plywood is commonly available in three-, five-, or multi-ply, with three-ply being the most prevalent. Three-ply offers strength, durability, and a more decorative appearance compared to other variants. Five-ply surpasses three-ply in strength, while multi-ply is suitable for exterior applications such as roofing due to its sufficient strength.
Number of plies on plywood
Apart from specialty plywood, the majority of plywood is accessible in boards or sheets that are either 3-ply, 5-ply, or multi-ply.
- The most common type of plywood is 3-ply. Since it is thinner (about 2-3 millimeters thick), it looks a little more decorative than thicker boards, so this option is great for indoor decor projects.
- At about 4 millimeters thick, 5-ply is the most versatile of the three types of ply. You can use this for indoor projects; however, it’s not suitable for building structures.
- Multi-ply refers to any plywood with seven or more plies. Stronger than 3-ply or 5-ply, this type is the best for structural projects, like framing or roofing.
When seeking strength, it is worth noting that plywood with fewer plies is still not as strong as a board with more plies. Therefore, opt for a board with more plies rather than a thicker board with fewer plies.
What is plywood used for
Plywood has a wide range of uses, making it an incredibly versatile and multipurpose building material. It is suitable for various applications such as furniture making, boat construction, manufacturing, table production, cabinetry, and more. Due to its versatility, plywood is an excellent choice for woodworking projects.
- Projects that require a little more support, like walls, floors, and roofs, where the panels can be tucked away from view.
- Projects that enhance the appearance of the home, like decor items, shelving, cabinets, and furniture.
The standard thickness of plywood sheets
Similar to sizes, plywood is produced in various thicknesses. The prevailing thickness is ½-inch, however, it can vary anywhere from ?-inch to ¾ inches.
Plywood ratings
Before selecting plywood, it is crucial to consider whether your project will be placed indoors or outdoors, and what kind of weather conditions it may face. The ratings of plywood will assist you in determining the most suitable option for your project.
- Exterior: Plywood panels have been waterproofed and can withstand inclement weather. Plywood with this rating is ideal for outdoor structures and projects.
- Exposure 1: These panels have been waterproofed and can withstand exposure during construction, but are not suited for long-term exposure.
- Exposure 2: These panels can be exposed to occasional moisture but aren’t fully waterproof. Use these panels for indoor projects.
- Interior: These panels can not withstand any moisture and are for interior use only.
- Structural 1: This is the strongest rating. Panels with this rating are designed to be earthquake resistant.
Plywood grades
There are four main grades of veneer: A, B, C, and D. These grades determine the quality and appearance of the plywood-veneer. Grade “A” is the most expensive and highest quality, while “D” is the least expensive and lowest quality.
The four grades of plywood, starting with the highest and most expensive, are as follows:
- “A” Grade: The veneer is smooth, sanded, and paintable. If there are any wood defects, they have been repaired with synthetic filler. This grade is ideal for furniture and cabinet doors that will be stained.
- “B” Grade: This grade is also smooth and sanded but may have minor repaired defects that are visible, such as patched knots or wood filler. No chunks of wood should be missing from the plywood.
- “C” Grade: This grade should be used when appearance is not important. The veneer is unsanded with several minor defects that need to be repaired. Knots, splits, discoloration, and sanding defects may be visible.
- “D” Grade: This grade is similar to “C” but with larger knots (up to 2 ½ inches) and similar defects.
From time to time, ratings can include two grades such as AC or BC, whereby the first letter represents the face veneer grade and the second letter represents the back veneer grade. On rare occasions, there might be a third letter indicating that the sheet is intended for exterior use.
In some cases, there may be a number following the plywood grade, such as B2. This indicates that the front side is graded as B and the back side is graded as a “2”. The grading for the back side ranges from best to worst, which are 1, 2, 3, and 4.
- A1, A2, B1 and B2 are good two-sided panels where the plywood would be seeting from both sides.
- A3, B3, and C3 are great for projects where the backside may not be seen, but it still needs to be clean (like the sides of the dresser where the inside won’t necessarily be seen).
- A4, B4 and C4 plywood ratings are adequate for projects where only one good side is needed. Think drawer bottoms or pieces where one side will be against a wall.
Categories of plywood
Softwood
Soft plywood is manufactured from softwoods like pine, redwood, or cedar, among others, and is appropriate for exterior frame and roof sheathing as well as subflooring. Softwoods can also be utilized for sheds, temporary flooring, and shelving. However, it is generally not advisable to use this kind of wood outdoors due to its deficiency in essential weather-resistant properties. Despite being a sturdy material, it lacks the necessary durability to withstand outdoor conditions.
Hardwood
Hardwood plywood typically consists of three to seven layers of hardwood such as birch, maple, oak, walnut, or other hardwood types. These layers are securely bonded at right angles to guarantee a sturdy outcome. Hardwood plywood is versatile and can be utilized in various applications like furniture, packing cases, sporting equipment, musical instruments, and other items that demand robust structures.
Aircraft
Aircraft plywood, which is constructed using hardwoods, possesses superior durability and can withstand heat and moisture. Its composition of thin veneers ensures a lightweight and flexible nature, without compromising on substantial strength. This makes it ideal for constructing airplanes, boats, and furniture designed to bear heavy loads.
Exterior
Exterior plywood, which is manufactured with weather- and water-resistant glue, is created to endure various weather conditions for an extended period. It is commonly manufactured with multiple layers to enhance its strength. In certain locations, it is constructed using sturdy woods, such as oak, to withstand more severe climates.
Lumber core
Lumber core plywood consists of a solid slab made from glued-together wood strips, which is sandwiched between two thin hardwood veneers. With its ability to securely hold screws, it is an ideal option for projects that necessitate these fasteners. However, the core can occasionally have voids, rendering it less strong.
Marine
Marine plywood is capable of withstanding moderate moisture due to its varnish, which is made with water-resistant exterior glue, aiding in repelling water, even though it is not fully waterproof.
Made from either western larch or douglas fir wood, this type of plywood is considered to be of the highest quality. Marine plywood must not contain any knotholes in order to be classified as such. It is highly suitable for outdoor furniture and decorative items such as planters or benches.
Overlaid
If you want plywood that is more decorative, you should consider using overlaid boards. Overlaid boards have the same plies as other types of plywood, but they also have a thin veneer of ornamental wood on top. This veneer not only enhances the appearance by making it more beautiful, but also provides a durable surface that can withstand water, scratches, and other forms of damage.
Structural
Also referred to as sheathing plywood, structural plywood is utilized to reinforce framing and building structures that will be concealed in the future. It is manufactured using a potent adhesive and can be employed both indoors and outdoors; however, it does not possess the same level of weather resistance as other variants.
