subfloor
Noun
Meaning
subfloor (plural subfloors)
(construction) The floor structure supporting and underlying the visible flooring or other finishing surface such as a carpet
Synonyms
Examples
Older homes may have solid hardwood flooring nailed directly on the joists--no subfloor.
The years and traffic had caused the first two layers to practically fuse together, and the first layer was almost impossible to separate from the subfloor.