What is BCX Plywood?

Plywood grading can be tricky to understand, and if you’re not a contractor you probably find the different grades as easy to understand as Egyptian hieroglyphics. Not to worry though, I’ll break this down in a way that anyone can understand, so you’ll have a solid understanding of BCX plywood and how plywood grading works.

There is a wide array of different plywood products available, so picking the right one for your project can be a challenge. BCX plywood is an extremely common plywood variant used for all types of exterior and interior applications.

To break it down into simple terms: the ‘B’ grade refers to the smooth face side, the ‘C’ grade refers to the rough ‘back’ side, and the X refers to exterior glue used to bind the veneers together.

Let’s take a closer look at the differences between different plywood grades, and how to select the right one for your project and budget.

Plywood Grading Explained

Plywood is a type of engineered wood made from layers of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees from each other.

It comes graded in four main veneer grades, A, B, C, and D. Each sheet will have two grades, such as AA or BC. The first letter is for the face veneer, and the second one is for the back veneer. Sometimes a third letter ‘X’ will also be present – which denotes them for exterior usage.

These are the different plywood grades explained:

“A” Grade: A grade plywood is the highest-quality plywood and hence the most expensive, it will be completely smooth and blemish-free, and can be painted right off the bat without sanding.

“B” Grade: Slightly less smooth than A-grade ply, it can have minor flaws and repairs and have football-shaped patches and wood filler applied to the wood surface.

“C” Grade: C-grade is another step down, and will feature some splits, discoloration, and knots up to 1 ½-inch in diameter.

“D” Grade: The cheapest grade of plywood is ‘D’-grade. It will have large knots and knotholes up to 2 ½” in diameter. Unlike the other grades, it doesn’t feature repairs to the surface to correct imperfections, so expect imperfections to be numerous.

If you’re talking about the uses for the various grades, then A and B are typically used for applications where the face veneer will be visible such as furniture, flooring, and rough construction projects. C and D on the other hand are typically reserved for uses where the face will be hidden behind something else like subflooring or for use behind siding.

plywood hanging over windows
Image source.

Most plywood paneling will have a different rating for the front face and the back one. This is because for most construction projects, only one side of the panel will be visible while the other remains hidden.

Keep in mind also that higher-grade plywood comes at an increased cost. It’s not always beneficial to use the highest-grade plywood out there, as the additional cost may not make sense in the case where the face veneer will be hidden.

As far as the “X” at the end of the plywood rating is concerned, such as in BCX, this indicates an exterior grade adhesive is used to bond the veneers together. This doesn’t mean that the plywood is completely waterproof, it’s more like the plywood is somewhat more water resistant than other plywood types.

There is also marine-grade plywood to consider. This is the stuff used for marine projects that will be surrounded by the harsh marine environment like boats, docks, and the like.

While it might sound like it, marine-grade plywood is not completely waterproof, although it can withstand a fair bit of moisture. The thing that sets marine grade plywood apart is that it has no voids or defects, which means no water is able to penetrate through the plywood and cause damage. It also uses a waterproof glue that can withstand prolonged moisture exposure.

BCX Plywood Explained

Now that you know the basics of plywood grading, let’s take a look at BCX plywood in particular. BCX has a well-sanded face on the ‘B’ front veneer and a rougher ‘C’ quality face on the back veneer.

This makes it a popular choice for all sorts of construction applications. The X at the end of the rating indicates that exterior grade glue was used for bonding the veneers, so it can hold up to exterior usage.

BCX plywood is commonly used for projects like shelving, paneling, stairs, wall sheathing, a base for siding, and for rough construction like work projects and truck and boxcar linings.

Common Uses for BCX Plywood

Because of its high quality and relatively inexpensive price, BCX plywood gets used a lot in various construction applications.


BCX is one of the most commonly used plywoods for building subfloors due to its combination of characteristics. It’s strong, moisture resistant, and relatively inexpensive, making it a good choice for a subfloor that will be covered in another material.


Wall sheathing is the material attached to the exterior wall framing and used to fasten a house’s siding to. As such, it doesn’t need to be perfect – making BCX plywood a good choice.

plywood sheathing
Plywood sheathing on house exterior. [Image source]
OSB is more commonly used for sheathing than plywood nowadays, but plywood is superior in moisture resistance and longevity, so people looking for a superior material will often go with plywood over OSB.

Roof Decking

Roof decking is the material that makes up the framing of your roof. These boards are what the shingles and underlayment are installed onto.

OSB is more commonly used as a roof decking material nowadays than plywood, but plywood is still fairly popular in some areas.

Rough Construction

Plywood – and specifically BCX plywood – makes a fantastic material for rough construction projects. Think of sheds, flooring for a semi-finished basement, barn interiors, and the like.

These types of projects require less fit and finish than others, so using plywood allows you to cut down on costs significantly. For these types of rough jobs, you can even get away with using cheaper grades of plywood like CDX.


Cabinets are typically made from high-quality ply if plywood is used at all, but you can still use BCX provided the inside of the cabinets will be covered or painted. The B side is suitable for cabinet exteriors, while the C side is rough and not ideal for applications where it will be exposed.

ACX Plywood

ACX plywood is similar in many ways to BCX plywood, but the major difference being the front-facing veneer is A grade rather than B grade. This indicates a very high-quality front veneer that is suitable for a multitude of exterior applications.

Of course, the C-grade rear face will be rough and feature some degree of imperfections and blemishes. The X indicates that exterior grade glue has been used, so it’s suitable for exterior applications.

ACX plywood is the standard choice when you need to use plywood that will be visibly exposed.

CDX Plywood

Another commonly used plywood grade, CDX plywood is ideal for exterior walls and roofs when cutting costs is a priority. Although it has lower quality front and rear faces than other plywood types, it’s still a solid choice for applications where the surface will be covered with other materials.

Featured image source.

Denis Gardner

I've loved tinkering and fixing things for as long as I can remember. So, naturally, I gravitated towards DIY and home improvement when I bought my first home. Nowadays you can find me writing about my passions or messing around with my newest tool!

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