Core terms · definition
The structural sheet material (plywood or OSB) fastened over floor joists that everything else — underlayment and finish flooring — is built on. Squeaks and unevenness usually start here.
Source: InterNACHI — Inspection Glossary: Subfloor
Where this term lands on a Columbus budget
The cost pages carry the current local ranges, and the guides explain what moves them. A published range becomes a project number only after someone looks at the site.