Subflooring
Definition and meaning of Subflooring in real estate.
Subflooring is the rough structural layer of plywood, oriented strand board, or concrete planks laid directly over the floor joists to provide a flat, stable base for the finished flooring.
In more detail
It is the intermediate structural layer between the floor joists and the visible floor finish, such as hardwood, carpet, or tile. Subflooring adds rigidity to the building structure, distributes weight across the joists, and helps prevent squeaks or sagging. In older homes, subflooring often consists of diagonal wood boards, while newer construction typically uses thick plywood or oriented strand board. Inspectors and builders look for water damage, delamination, or unevenness in the subflooring before installing finished floors.
Key facts
| Category | Property Types & Construction |
|---|---|
| Common materials | Plywood, oriented strand board, or concrete |
| Installed over | Floor joists |
| Watch out for | Squeaking, swelling, or water damage from plumbing leaks |
Before laying the new hardwood flooring in the living room, the contractor screwed down the squeaky subflooring sheets to the joists below.
Frequently asked questions
What causes subflooring to squeak?
Squeaking is typically caused by wood friction when nails loosen over time, allowing the subflooring sheets to rub against the floor joists as people walk across the floor.
Do you need underlayment on top of subflooring?
Yes, for many finishes like tile, luxury vinyl plank, or carpet, a thin layer of underlayment is placed on top of the subflooring to smooth out imperfections and dampen sound.