The Different Plywood Grades + Grading Standards

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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, here’s how to tell the different types of plywood grades apart with the guidance of our resident woodworkers. 

The Different Grades of Plywood

You may not know, but 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. 

person carrying plywood

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, we 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, you must expect it to include 2.5 inches in diameter knots. It’s not the highest quality plywood, but it’s the cheapest. 

choosing plywood

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. 

wood

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, our experts only recommend 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.  

Veneer

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 CombSound & Repaired Knots in CombinationRepaired KnotsMineral StreaksSapBlended Repaired Tapering Hairline Splits
AMaximum of 12 (4 to ¼ inch)NoneNoneLight/Minimal5% (1)1/16-inch x 6-inch (2)
BMaximum of 24 (16 to ¼-inch) 44 to ⅛ inchVery few to 8 inchesMaximum of 20% (2)⅛-inch x 8 inches (4)
CNo Limitation84 to ½ inchUp to 12 inchesYes3/16-inch x 8 inches (4)

Grading

Sound Tight KnotsKnotholesRepaired KnotsSound Tight BurlsMineral SapRough CutSplits or Joints
1Maximum of 16 (Up to ¼-inch)NoneNoneYesYes/YesTwo 8-inch diameter areasNone
2Maximum of 16 (Up to ¼-inch)Fully Repaired8 to ½ inchYesYes/YesYesLight
3Maximum of 16 (1/2 -inch to 1 ½-inch)⅜-inch to 1 inchNone (1)YesYes/YesYesTwo 8-inch surfaces
4YesMaximum of 4 inchesNoneYesYes/YesYes5% of panels

Different Plywood Types

Baltic Birch

These material types are cut clean and pleasing to look at. You can use them on pieces of furniture with no problem.

Baltic Birch Plywood

CDX

CDX plywood is moisture-resistant, so we 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, you must 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. 

pressure treated plywood

CDX sheathing

As discussed earlier, the face side of this material is graded “CD,” and X stands for its suitability for outdoor exposures. You’ll encounter these boards when working on external walling and roofing. 

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. If you read our brief guide, it’s obvious that not all boards have the same durability levels or characteristics. 

Plywood Storage Bench

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, we urge you to check 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 Weigh

Conclusion

Looking at the plywood grading labels alone can easily give you the gist of how the material suits your project. However, our resident woodworkers still recommend doing a thorough 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!)  

Robert Johnson is a woodworker who takes joy in sharing his passion for creating to the rest of the world. His brainchild, Sawinery, allowed him to do so as well as connect with other craftsmen. He has since built an enviable workshop for himself and an equally impressive online accomplishment: an extensive resource site serving old timers and novices alike.
Robert Johnson
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