"Gee, I wonder how my subfloor's holding up." No, it's probably not something you think about often. In fact, you may never consider your home's subfloor--until it begins squeaking or you have to replace the covering over it (see the Carpet Fix-It Guide, the Resilient Flooring Fix-It Guide, and the Wood Flooring Fix-It Guide). It just does its job day after day: supporting the flooring you walk on. Let's call a quick meeting of the Fix-It Club to take a look at the subfloor.

How Does It Work?

A subfloor is a floor laid on top of the floor joists, to which a finished, decorative floor is fastened. If your home's floor is of poured concrete, that's the subfloor. Plywood or planks also provide a solid platform to which tile, vinyl, hardwood, carpet, etc. can be fastened with nails or adhesives. To hold the finish flooring, the subfloor must be stable, relatively smooth, and waterproof.

What Can Go Wrong?

The most common problem with a wood subfloor is annoying squeaks when someone walks across the floor. Squeaks occur when pieces of wood rub together. Concrete subfloors don't have this problem, but they can become water damaged and crack.