CDX vs. OSB: What Is the Right Choice for You?

Two of the most popular types of plywood, CDX and OSB both provide your home with the protection that it needs. It is important that you know which type of plywood you need to use and where to use it. 

Differences Between CDX and OSB

To the untrained eye, every piece of plywood looks the same. However, different types of plywood have their own unique benefits and applications. Discover more about OSB and CDX plywood today.

What is CDX Plywood?

What is CDX Plywood

In order to understand what CDX plywood is, we need to break down what the three letters in the name mean. The C stands for the veneer grade of one strip of plywood, and the D stands for the same thing. The X refers to the glue used to attach both veneers. A single sheet of CDX plywood has two strips of plywood, one a C and one a D, glued together.

Every sheet of plywood comes with a grade. Plywood bearing a C-grade is not sanded and contains defects and knots under 2″ in diameter. When installing C-grade plywood in your subfloor, these knots and defects do not matter. D-grade plywood is not sanded and contains defects and knots above 2” in diameter.

The “X” in CDX refers to the type of glue used to attach the two different types of plywood. Some types of plywood rely on a standard adhesive. CDX plywood uses a specialized adhesive that makes CDX plywood a great choice for use inside and outside your home.

What is OSB?

What is OSB

OSB stands for Oriented Strand Board. Made from wood strands that are between 3” and 6” in length, OSB is an engineered wood panel that provides plenty of versatility.

OSB manufacturing allows manufacturers to use the entire tree during the milling process. Framing lumber, lumber used for finishes, and other pieces of wood cannot contain knots and other defects. That’s not the case for OSB.

During the manufacturing process, the manufacturer takes the strands and mixes them with a waterproof resin. Once the mixing process is complete, the strands go through the bonding process under immense heat and high pressure. This creates the large sheets of plywood that you see when you walk down the aisle at your local hardware store or lumber yard.

What Are the Differences Between CDX and OSB?

While many people think that all types of plywood are interchangeable, that’s not the case. OSB and CDX each come with a unique set of benefits that make them great choices.

However, it is important to understand that these benefits lend themselves to specific uses for these types of wood.

For instance, OSB is more water-resistant than CDX. CDX absorbs and loses water easily, allowing it to go back to its normal shape. Thanks to the resin used at the beginning of the OSB manufacturing process, it does not absorb water easily. However, that same resin makes it harder for OSB to lose the water that is absorbed.

CDX plywood is more expensive than OSB. As is the case with any type of lumber, different sizing results in different prices. Thinner sheets of CDX cost around $20.99 per sheet while thicker sheets can run upwards of $40.99 per sheet.

OSB plywood pricing starts closer to $15.80 per sheet while thicker sheets can cost as much as $32.99 per sheet.

The most important difference between OSB and CDX involves their applications. In the same way that you wouldn’t use the same type of lumber used for framing to build a large deck on your home, it’s important to use the right type of plywood for the job.

Since subflooring doesn’t face exposure to moisture, CDX is a great choice. It’s thickness and durability make it an excellent option for reinforcing floors. If you live in an area that doesn’t experience a lot of rainfall, CDX also has roofing applications.

OSB is a more popular option for sheathing, the base layer of your roof. Thanks to its water-resistant nature, OSB is a great option when looking for something to install under shingles, roofing metal, or the roof finish that you choose.

Both OSB and CDX provide plenty of benefits and practical applications. In fact, it is virtually impossible to build a home without using at least one of these types of plywood.

Understanding the benefits of each and their most common applications ensures that you choose the right type of lumber to protect your home from the elements.

When meeting with your contractor, make sure to let him or her know about the type of plywood that you want to use.