Flooring · Costs, budgets and timelines · Updated November 2026
Subfloor Repair Cost: Signs, Causes and What to Expect
The subfloor is the plywood, OSB or plank layer under your finished floor. Replacing damaged sections typically costs $3–$10 per square foot, plus the cost of removing and replacing the flooring on top.
Signs of subfloor damage
- Soft, spongy or bouncy spots when you walk.
- Squeaks that get worse over time.
- Cracked tiles or grout, or popping floor planks.
- Sagging or dipping areas.
- Musty smell or visible staining near toilets, tubs, dishwashers or exterior doors.
If floors slope across a whole room or doors stick, the cause may be structural rather than the subfloor; see sloping floors.
Common causes
- Slow leaks from a toilet seal, tub, shower pan or appliance line.
- Moisture from a crawl space.
- Termites or other wood-boring insects.
- Fasteners that have worked loose.
What affects the cost
- Area damaged: a few square feet by a toilet vs. a whole room.
- Access: crawl spaces and unfinished basements make repairs easier.
- Joist damage: rotted or cracked joists underneath need sistering or replacement.
- Finished flooring: tile is more work to remove ($2–$7 per sq. ft.) than carpet or vinyl.
- The source: the leak or moisture problem must be fixed first, or the damage returns.
Plan for it in flooring quotes
Since subfloor damage is often hidden, ask flooring and bathroom contractors to include a per-square-foot price for subfloor replacement in the quote. See our flooring cost guide.
Cost figures are national ranges from the sources listed in our flooring cost guide, not a quote from FixFinch or any contractor.