Plywood Grading 101
Updated: Oct 27, 2020
By: Chelsea Rodgers
Plywood can be a woodworker’s best friend. Plywood can be used for shop jigs, shelving, cabinets, book cases, work benches, the list can go on and on. Plywood can really be useful If your shop is set up in a way that you can break down full sheets, or even half sheets so you can rip it into whatever sized 1-by you need. Not all plywood is made the same, and are very particular to types of projects to be used in.
Plywood can also be extremely confusing and frustrating, if you don’t fully understand the different plywood grades. If you’ve every stepped inside a hardwood dealer you know they have more plywood then you ever knew existed. But even if you find yourself in Home Depot for your plywood purchases, it still is helpful to understand the plywood grades.
Plywood’s standard grading system is A, B, C, and D. A-grade plywood is super-clean, with little or no blemishes. A and B grade are both very high quality, and so they will cost quite a bit more than lower grades. In the lower grade plywood, the knots in plywood are replaced with football-shaped patches. With the higher grades, A and B plywoods will have far less of these.
You’ll notice that some plywoods are graded with 2 letters, not just one.
That’s because typically only one side of a sheet of plywood is exposed. Meaning they can keep cost down by only making 1 side worth a dang. So, when you see A-C plywood, that means the better side is a blemish-free, very clean ‘face’. And the back side will be much lower quality.
Another example is C-D, also called CDX plywood. This is your typical construction grade plywood. When you see the X in the grade, that’s referring to an exterior rating. It can handle the outdoors for a limited time, but must be covered for long term. It’s common for wall covering and roofing.
In some stores you’ll see AA, in others you’ll see A1. Some plywood manufacturers use a number rating for the back side. Just like with letters, they’re a simple grade in quality, 1 being the best. So, if you find anything that’s labeled A-4 or B-4, it’s got a high-quality face, while the back is meant to be covered, or left un-exposed. And don’t get confused, A-2 does not mean A on both sides. It means something more in line with A-B, as in the back side is not the same quality as the face.
Common Plywood Grades at Home Stores
Construction grades may be labeled Construction Sheathing. Within this category is the CDX plywood, mentioned above. This is cheap plywood, so even though it’s made for construction, you might consider using it for shelving or simple work benches where appearance isn’t that important. Also, the CDX will be rough to the touch. You can sand it down a bit if you want, but don’t expect great results
Plywood labeled Sanded, Premium, or Top Choice has a much better surface and works great for any shop project. Premium (A) sanded plywood may only be pine or whitewood, and still could cost upwards of $100.
But if you find some B-C Sanded pine, then you’ll be saving some real money and still getting quality product. You’ll also find Baltic Birch plywood in most home stores. This, is the best plywood for shop furniture, jigs, and sleds. The surface and the edges look great, it’s very stable, and it’s great to work with. But obviously, you’ll pay more for this variation.
Oak, Birch, Maple, and other hardwood plywoods are typically cabinet grade plywoods that you’ll pay a premium for. At a hardwood or plywood dealer, you’ll likely find even more variations of cabinet grade plywoods. There, you can also pay even more to get them pre-finished. This will be some high-grade cabinet material and if you’re going for a professional kitchen cabinet look and feel, this may be your best bet. But be prepared, pre-finished hardwood cabinet grade plywood in 3/4″ 4×8 sheets may cost over $120.
For outdoor projects where there will be exposure to moisture, you’ll want to look at the pressure treated plywood variations. For the most extreme wet conditions, look at the marine grade. This is not cheap, but the wood is treated to handle very wet conditions, plus the glue is water proof.
To wrap this up, we would suggest that for basic furniture around the house, simple cabinets, book cases, etc., stick with Sanded B-C pine. It’s cheap, it’s smooth, plus when stained it will match your trim work and drawers if you’re building with pine wood. And a step up from that would be Baltic Birch. It’s a great plywood, and its light colored so staining to make it match other woods is pretty easy.