Different Types of Subfloor Material

Your choice of subflooring can depend on environment and flooring choices

sub-flooring installation
sub-flooring installation. Photo Butch Dill / Stringer/Getty Images

The subfloor is the bottom-most layer of your floor. There are several materials you can use as subfloors, depending on the type of finish flooring that you are using. The most commonly used types of subfloors are wood and concrete, but there are other subflooring alternatives that you might consider. The installation process including moisture and thickness of the subflooring material are critical for a successful installation so make sure moisture, pattern, and glue/nail use to attach the subflooring are adequate to support the installation.

Wood Subfloor

If you are installing a wood subfloor be aware that you can use a nail-down method, a floating installation or a glue-down method. Normally, and for economical reasons, wood subfloors are made of old wooden planks or, plywood.

No matter which installation method or product you use, it is important to remove all nails and screws and to make sure that the wooden planks are leveled. We recommend using the nail-down installation over concrete floors.

Plywood Subflooring

This is the most used subflooring type beneath wood and vinyl floors. It works well because it can adhere to the wood joists and ensure a flat surface. If your plywood surface is not level, you will need to sand it to a leveled surface or use a subfloor leveling compound.

Avoid using plywood in areas where it will get wet as it may buckle over time. Be sure to glue down all loose boards to minimize the risk of squeaks and shifting.

These squeaking sounds can also be prevented by applying a coat of subfloor caulking adhesive to the top of the wood joists before screwing the wood to them.

Tongue-and-groove plywood is a highly recommended subfloor material because its edges interlock to each adjoining sheet, creating a strong and secure base for any finished flooring.

 Engineered or solid wood flooring that is less than 1/2" thick can be installed over a plywood subfloor. One important recommendation is to put liquid nails first preventing squeaking with time. Also, you might want to leave just a little gap in the grove for future expansion.

Concrete Subfloor

Concrete subfloor must be completely cured before installing your new flooring material. You can also opt to install a cement backer subfloor that will be screwed into your floor joists to create a solid and reliable surface. A concrete subfloor produces a waterproof surface that works great in wet areas. A cement backer subfloor can be used underneath stone or ceramic tile flooring.

One of the most important aspects of a concrete subfloor is that you can often remove the old flooring surface without damaging the concrete surface. However, be aware that for best results, moisture shall be removed from underneath or from the concrete before installing any flooring material over it. Concrete will take many days to cure and get all mositure out of it.

A Different Option: Plastic Subflooring

Plastic is another subfloor material that you might use in places where water can be a problem. Plastic subflooring can be installed under ceramic and stone tiles.

It might be installed in a basement to create a moisture barrier that prevents water from damaging other portions of the flooring. Plastic subfloor can also be installed as interlocking pieces as a floating subfloor, or it can be screwed or nailed in place. Plastic subfloor sheets are often used as sound barriers.

OSB Subfloor

Oriented strand board, or OSB, subflooring can be nailed or screw into the floor joists to create a solid base for your main flooring. It can also be installed as a floating subfloor over concrete, although your floors might creak. OSB board is often used when laying hardwood and laminate flooring. Ensure that the OSB board is flat before laying your flooring.  If you are installing floating floors that are less than 1/2 in thick, it is preferable to add one 3/8 inch layer of plywood underlayment to add stability.

 

Other Types of Subflooring

There are other types of subflooring, such as vinyl and engineering solid wood. You can also consider the option of laying your floor directly over beams and joists but you might have some issues later on.