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Wondering Which Plywood Is Best For Your Project? This Guide Can Help


At Keim Home Center, we are here to help you get your projects started so that you can end with first-rate craftsmanship. Our lumber yard has been producing high-quality wood products for over four generations. We love to share our passion for well-built projects with our customers.

When considering whether plywood is the right choice for your next project, consider where and how you will use the material. This engineered wood can differ in type and number of ply, rating, grades, and sizes. And, it’s not one-ply-fits-all. Thin sheets of veneer, or ply, are glued together to make a low-cost, popular building material used in everything from cabinets and floors to roofing and sheds. So, let's walk through what makes a difference in construction, building needs, and project purpose. 

Popular Ply Numbers and Sizes

To construct plywood, an odd number of panels, or veneers, are glued together in alternating right angles forming a strong, cross-grain pattern. Plywood comes in 3-ply (2-3millimeter thick), 5-ply (4 millimeter thick) and multi-ply, which is 7-ply or more.

At Keim, we offer plywood sheets in 4 x 8 feet or 5 x 5 foot panels. The thickness of the boards vary from ⅛-inch to ¾ inch. Smaller, pre-cut project panels are also available and oftentimes, easier to use for small-scale projects. 

Pro-Tip: To be clear, any number of ply can come in any thickness, with the thickest boards with the highest number of plys being the strongest and heaviest. Consider what level of strength your project would benefit from while looking at how heavy the end result will become. We recommend multi-ply for any structural projects, such as roofing, framing, sheds, or any project that bears weight. 

Types of Plywood Available

Project plywood panels are perfect for simple and fast DIY projects. Once you know your measurements, select these pre-cut panels. Read further to determine what number ply, grade and rating to choose.

Sanded plywood simply means that the top and bottom (or face and back) of the panel are sanded smooth and work beautifully where visibility matters. For instance, if you are building a cabinet, shelves or paneling, you can paint or stain this product for a lovely, finished look. 

Hardwood plywood is constructed with birch, maple, oak or other hardwoods. This makes the material strong and heavy and great for furniture that needs to bear heavy loads. 

Structural plywood is ideal for large, exterior construction where structural integrity is essential and its unfinished surface is no issue. Multi-ply structural plywood is an inexpensive, common method for framing, flooring, beams, bracing and more. 

Deciphering Ratings and Grades of Plywood 

Rating determines where the plywood is best suited for in terms of being weather resistant. Grades refer to the quality of appearance on the surface of the paneling. 

Plywood Ratings 

Choosing the correct rating will make the difference between the longevity of your construction and determine whether rot or weather events will affect your hard work. There are 5 ratings of plywood materials:

Exterior is the rating to select if your project will have long-term exposure to moisture. This waterproof material will avoid rot for years to come.

Exposure 1 is perfect for places where moisture exposure is temporary, such as during construction of a home that will then become protected from rain later on.

Exposure 2 indicates that the wood is not fully waterproof but can resist rot if lightly exposed to some mild intermittent moisture. This product is used for interior projects. 

Interior rating means that this material is strictly recommended for interior use only and should never be exposed to water of any kind.

Structural 1 is the strongest rating and is designed to withstand earthquake level events. This plywood is rated for seismic retrofit construction. 

Plywood Grades

Think about how you would like the surface of your project to look and feel when deciding what grade plywood to purchase. Grades range from A to D, with A having the most finished look.

A-Grade plywood shows very few imperfections with an even, sanded surface. Any knots have been eliminated or repaired with synthetic filler during construction. This grade is popular for cabinets, furniture, or projects demanding a beautiful, soft finish. 

B-Grade plywood features the same finished look as A-grade but may have started out with more imperfections or knots, 1 inch or less, that have been repaired during construction.

C-Grade is great for use where its unsanded face and back will not show. This subfloor quality material may feature discoloration, sanding defects, and knots less than 1.5 inches. 

D-Grade is similar to C-Grade but the knots may be larger - up to 2.5 inches across. 

Pro-Tip: Because the multi-veneers are glued together, it's possible to select two grades on the same piece of plywood. Thus, you will also see plywood available in two-letter classification, such as AB. This simply means that one side is A-Grade while the second side is B-Grade. 

When you’re ready to start your next project, come visit us at Keim. Our friendly and knowledgeable staff in the Tools or Building Materials departments are ready to assist you today. We are always happy to discuss your project plans and set you up for success, including providing tool and equipment rentals. At Keim, we treat your projects like our own. Share your ideas with us, and together, we’ll create the best quality projects from top materials using the highest standard tools.

Located on 50 acres in the rolling hills of Holmes County, Keim is the destination and trusted source for your home, building, and woodworking needs. Founded in 1911, our fourth-generation family business is dedicated to caring for your project like we care for our own.