Plywood is a durable and versatile material, making it highly suitable for indoor and outdoor projects. The only problem is not every woodworker knows the type of plywood they need, leading them to waste money on plywood with wrong grading specifications.
To help you avoid this mistake, I’ve made this guide on how to tell the different types of plywood grades apart.
The Different Grades of Plywood
US plywood manufacturers must adhere to a general grading system to determine the quality of the material they’re selling. If you shop for your next project, you’ll notice the plywood veneer grades labeled A, B, C, and D.
In some wood boards, this grading system also includes numbers 1 to 4 that help determine which types of wood have higher quality. Here’s how to tell them apart based on wood quality.
Softwood
Every softwood plywood sheet will come with two-letter specifications, where the first letter refers to the face veneer quality and the second to the back veneer. Between these two grades, you’ll be able to tell the number of knot holes the back and face veneers have.
A-Grade Plywood
If your softwood plywood veneer is graded A, it can be sanded smooth. And since it has a smooth surface, it’s almost ready for painting work. You’ll also have no issues on it regarding large knots or repairs.
B-Grade Plywood
For types of plywood under the B grading category, their appearance carries football-shaped patches. Despite having a solid surface, this patchwork design meant it had knots sized at least 1 inch and minor flaws.
C-Grade Plywood
The grades of plywood under the C category include discolorations and a few splits on the surface. Upon close inspection, I also noticed that it has one ½-inch of tight knots and an inch of knotholes.
D-Grade Plywood
If your material is graded D in its back or face veneer, expect 2.5 inches in diameter knots. It’s safe to say that this isn’t exactly top-tier plywood quality, but it does come with a silver lining—it’s usually the most budget-friendly option out there.
These grades of plywood work best if you want a natural wood appearance or for painting work.
Domestic Hardwood
Besides the grades of plywood categorized in A to D, domestic hardwood variations are also quality graded from 1 to 4. The letter grading system refers to the wood’s face veneer, while the numeric categories indicate the back grade (where 1 is the highest quality).
Like softwood, domestic plywood with a face grade of A is already repaired to appear smooth. It’s the type of plywood or lumber best used for making cabinets and furniture. Meanwhile, a plywood panel under face grade B features a natural wooden surface with few flaws.
Domestic hardwoods with face grades of C and D are materials you wouldn’t want to use for cabinets. This scenario is especially true if you don’t want your furniture to have a natural wooden appearance.
According to the ANSI [1] numeric grade system for the back veneer, a wood sheet under 1-2 categories have none or repaired knotholes. It means that these wood types are almost blemish-free.
Although hardwoods under category 3 have some obvious defects, you can ask for these splits, joints, and holes to be repaired immediately. It’s very different from plywood with grade 4 back veneers that include 4-inch knotholes and other open defects.
Imported Hardwood Plywood
Shop Grades
Shop-graded hardwood panels are often sold in a 60-inch x 60-inch variation. If you look at it closer, you’ll notice that it’s made of 1 to 3 splits. Its length goes up to 10 inches and width up to ¼ inch.
C/C
Although categorized as hardwood, this is the type of plywood that’s not sanded. Because of this, I only advise using it for structural projects.
CP/CP
This plywood type only includes single front and back veneers with open defects and repaired splits. Since it’s designed with great sides, you’ll often encounter them in laminating tasks.
BB/CP
These plywood pieces appear with light mineral streaks on their surface and 3 to 6 colored patches.
BB/BB
These plywood pieces appear with light mineral streaks on their surface and 3 to 6 colored patches.
B/BB
Imported plywood under B/BB grades has clear and defect-free face sides. It also includes uniform colors in the front and 3 to 6 color patches at the back veneers.
Plywood Grading Standards
Red and White Oak (Rotary-Cut/Quarter-Cut/Plain-Sliced/)
Grading | Pin Knots & Small Burls Comb | Sound & Repaired Knots in Combination | Repaired Knots | Mineral Streaks | Sap | Blended Repaired Tapering Hairline Splits |
| A | Maximum of 12 (4 to ¼ inch) | None | None | Light/Minimal | 5% (1) | 1/16-inch x 6-inch (2) |
| B | Maximum of 24 (16 to ¼-inch) | 4 | 4 to ⅛ inch | Very few to 8 inches | Maximum of 20% (2) | ⅛-inch x 8 inches (4) |
| C | No Limitation | 8 | 4 to ½ inch | Up to 12 inches | Yes | 3/16-inch x 8 inches (4) |
Grading | Sound Tight Knots | Knotholes | Repaired Knots | Sound Tight Burls | Mineral Sap | Rough Cut | Splits or Joints |
| 1 | Maximum of 16 (Up to ¼-inch) | None | None | Yes | Yes/Yes | Two 8-inch diameter areas | None |
| 2 | Maximum of 16 (Up to ¼-inch) | Fully Repaired | 8 to ½ inch | Yes | Yes/Yes | Yes | Light |
| 3 | Maximum of 16 (1/2 -inch to 1 ½-inch) | ⅜-inch to 1 inch | None (1) | Yes | Yes/Yes | Yes | Two 8-inch surfaces |
| 4 | Yes | Maximum of 4 inches | None | Yes | Yes/Yes | Yes | 5% of panels |
Different Plywood Types
Baltic Birch
These material types are cut clean and pleasing to look at. Their inherent resistance to warping and their ability to hold screws securely make it a preferred choice for both amateur craftsmen and seasoned professionals. I’ve used them on pieces of furniture with no problem.
CDX
CDX plywood is moisture-resistant, so I highly recommend them for constructing work tables and storage bins.
Sanded Pine
A sanded pine material has smooth face and back veneers that are highly suited for building boxes and cabinetry.
Ideal Plywood Type for Indoor Use
You’ll have no issues finding materials suited for indoor use because it’s widely available in the market. However, remember that wooden boards in this category are not meant to withstand harsh outdoor conditions.
Oriented Strand Board
This material is often called OSB for short or a “wafer” board. It’s composed of glued wood chips to create a unique patchwork. You can easily buy them at local home repair stores.
Ideal Plywood Type for Outdoor Use
If you see a wood grade with “X” as the third letter, it indicates that it’s durable enough to withstand an outdoor project. These materials can stand strong against harsh weather conditions like rain or extreme heat.
CDX sheathing
As I mentioned before, the face side of this material is graded “CD,” and X stands for its suitability for outdoor exposures. These are the boards you’ll want to have in your arsenal when you’re working on external walling or roofing projects.
Pressure-treated plywood
True to their name, these wooden boards are treated with chemicals that keep molds and mildew away from their surface. Even without a protective coat or paint, it should hold well for the years to come.
Choosing the Right Grade Of Plywood For Your Project
Project Plywood vs. Construction Plywood
When deciding between these plywood grades, you must consider where the material will be used. As I’ve explained in this brief guide, it’s obvious that not all boards have the same durability levels or characteristics.
These differences specify if it’s suited for indoor projects or construction settings.
Safety Risks to Consider
Plywood Glues
These materials include adhesives like urea formaldehyde that may pose health hazards. To be safe, I highly encourage checking if the material has an “E” rating, which means it’s low on formaldehyde.
Plywood Dust
Dust from treated lumber can be harmful, so wear safety masks and goggles to avoid undesirable consequences of long exposure to the material.
Must Read: How Much a Plywood Sheet Weighs
Conclusion
Looking at the plywood grading labels alone can easily give you the gist of how the material suits your project. Yet, in my experience, I’d still strongly recommend going the extra mile and conducting a meticulous inspection.
After all, these boards varied individually in flatness, grains, and color. Remember to consider the environment you’ll be using the plywood.
(Want to learn more about in-depth facts about wood? Then know more about the S4S, S3S, and S2S lumbers and their differences!)
You've probably seen his down-to-earth wisdom in USA Today, Bobvila, Family Handyman, and The Spruce, where he has shared commentary and guidance on various woodworking topics.
Robert is the brain behind Sawinery, where he aims to share tips, tricks, and a passion for all things carpentry.
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