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What is CDX?

By August 10, 2021Engineered Lumber

What is CDX?

You probably have heard someone talk of CDX, or maybe you have actually used it before. However, more than half the number of people who have heard of or used CDX do not really know what it means, what the letters stand for, its qualities and its uses. So let’s start by finding out what is CDX.

What is CDX?

CDX is a type of plywood. Basically, plywoods are thin veneer sheets that are glued and held together with linking plies. Plywoods are known for their strong resistance to cracking, breaking, or twisting.

There are different grades/classes of plywood which are represented by letters A, B,  C and D. As you would expect, A is the most expensive and the best quality, in terms of the number of knots on it. The less the number of knots, holes and repaired defects the more expensive the plywood.

If so, it therefore, means CDX has the most number of knots and defects, making it a lower grade plywood.

C in CDX means one side of the plywood is of grade C, and the other is of grade D.  Not that it matters a lot in the tasks they are meant for, but usually, the part of better grade is used on the more visible side while the one of lower grade is used on the less hidden side.  X stands for exposure, which is the type of glue used to bind the plywood together. However, note that the grading is not about the quality but the appearance of the wood because CDX is pretty strong and resistant to damage.   Besides, the tasks for which CDX is meant for requires more quality than good appearance.

Exterior uses

Roof sheathing

Roof sheathing is one of the most common exterior uses of CDX. Usually, this plywood is passed through multiple processes that make it very strong and water-resistant. This makes it a good choice of material as far as exterior applications are concerned. Besides, in cases when it absorbs water (since it is not waterproof), CDX will dry fast and lose the water over time and get back to its original size.

Construction of crates and boxes

Since aesthetic value is not a big deal when it comes to crates and boxes, CDX is among the few, more preferable options as far as crates are concerned. Their dimensional stability and resistance to water damage is also a plus, and so is their solid-tough nature.

Interior uses

Garage shelves

This plywood may not be the best choice of materials for making shelves. However, this is not because of its quality but because of the appearance, which is why nothing is lost if it is used to make a shelf in the garage or workshop.


To reduce bowing and flexing, the incredible strength of CDX always comes handy. The plywood is mostly used as a sub-floor to ceramic floor finishings like in kitchens and bathrooms. Its economic nature also makes it easier to get and in enough quantities.

CDX is possibly the most available and affordable plywood in the market. Visit your favorite lumber store and make your purchase.