What is a Subfloor?

subfloor of new construction homeA subfloor is the immediate layer of planks or plywood that is laid over the floor joists. It is the base for whatever else is laid upon it such as carpet, linoleum, laminate or bamboo flooring, between which there is a layer of underlayment. Underlayment is the materials used over the subfloor to create a stable and smooth surface for the finishing material.

In construction, the subfloor is one of the most fundamental elements of interiors. Without a stable, level floor, whatever is placed upon it will not live up to its claims of durability, longevity or other virtues. In fact, a poorly installed subfloor can be the downfall of the entire flooring system, whatever finishes are chosen.

In the old days, subfloors were constructed out of straight or diagonal planks of wood whereas nowadays, plywood is used more commonly instead because it is cheaper, lighter and easier to install.

There are also concrete subfloors and these too must be smooth and stable, as well as dry in line with the construction standards effective for the area.

Subfloor Applications

It’s necessary to be mindful of your subfloor before you go shopping for flooring finishes. The kind of subfloor you have will dictate the kind of finish you can put down. For instance, any finish that is installed using staples or nails will need a wood subfloor so that the fasteners can be affixed. Concrete is not suitable in such instances.

Concrete is, however, a suitable base for installation methods that involve gluing such as carpeting or hardwood planks, both of which are glued directly to the subfloor. The concrete must be fully cured and 100% dry in order for the glue to properly adhere and to ensure that no moisture makes its way into the wood or carpet, compromising the quality and longevity. Glue-down installation is the most straightforward method for anyone with limited skills in carpentry or flooring.


Installation is also fairly simple with floating floors since the floor is not fastened by mechanical means to the subfloor, which can be wood or concrete. A thin pad is positioned between the subfloor and the wood flooring and a wood adhesive is applied to the tongues and grooves of each plank to hold them together.

New developments in hardwood flooring products mean that there are glueless installations now available. Utilizing a locking system akin to the Clic system of laminated floors, it means that the subfloor can be concrete or wood.

For a do-it-yourself handyman, locking hardwood floors is a comparatively simple installation project because no special equipment is required and there is no need for any adhesives, staples or nails. A tape measure and some basic hand tools are all he needs.

So the subfloor of a house is more important than you may at first think. When you are planning to remodel, it’s vital that you take into consideration the kind of subfloor that exists before making any decisions about the floor coverings you choose. Otherwise you may be forced to install a new subfloor before you can even look for the finishes.

Still, once you’ve determined your needs, you may find that you’ll be able to install your new floors yourself depending on the methods required, and that will save you plenty of money that you can spend on a greater variety of choices.

photo by Blaine Hansel / CreativeCommons