subfloor
nounEtymology From sub- + floor.
1
Business, Construction, Manufacturing The floor structure supporting and underlying the visible flooring or other finishing surface such as a carpet
- The original floor was still there: wide boards, laid tongue-in-groove, not the inferior subfloor they had predicted.2007 May 6, Tracie Rozhon, “The Good Bones Were Still There, Hidden Under the Additions”, in New York Times: