Subfloor replacement cost: a bathroom, a room or a kitchen, per square foot, by state
A 12 by 12 room, 144 sq ft: about $775 to $1,050, typically $875. That's the old subfloor cut out and 3/4 inch tongue and groove plywood put down, plus the contractor's overhead, profit and sales tax. Everything in, it runs $5.25 to $7.25 a sq ft. Taking up the finished floor, joist repairs, drying and the new floor covering are extra.
Anthony Hicks30+ years in construction. Updated November 5, 2026.
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What it costs
| Job | Cost |
|---|---|
| A bathroom floor, 50 sq ft | $300 to $425 |
| A 12 by 12 room, 144 sq ft | $775 to $1,050 |
| A kitchen, 200 sq ft | $1,050 to $1,450 |
About $5.25 to $7.25 a sq ft, everything in.
Totals include the contractor's overhead and profit (20%) and the state's average sales tax. Prices as of November 2026.
What’s in these numbers
Each total is a typical job, priced the way a contractor’s estimate is priced:
- 3/4 inch tongue and groove plywood subfloor, the old subfloor cut out, on the area shown.
- Overhead and profit: 20%, the standard markup on a contractor’s estimate.
- Sales tax on the materials, at the state’s average rate.
Not in them: taking up the finished floor and putting a new one down, joist repair or sistering, drying out wet framing, moving the toilet or cabinets, and permits.
How thick a subfloor
The code’s panel table sets the farthest apart the joists can be for each panel (IRC Table R503.2.1.1(1)):
| Panel | Joists up to |
|---|---|
| 24/16 span rating, 7/16 inch | 16 inches apart |
| 32/16 span rating, 15/32 or 1/2 inch | 16 inches apart |
| 40/20 span rating, 19/32 or 5/8 inch | 20 inches apart |
| 48/24 span rating, 23/32 or 3/4 inch | 24 inches apart |
| Single floor (subfloor and underlayment in one), 23/32 or 3/4 inch, 24 o.c. | 24 inches apart |
The 3/4 inch tongue and groove panel priced here covers joists up to 24 inches apart. Unsupported panel edges get tongue and groove joints or blocking unless an underlayment or finish floor goes over them as the table’s notes allow.
When a subfloor is replaced
- Water damage. A leak under a toilet, tub, dishwasher or water heater can soak and soften the subfloor; the water damage restoration guide covers drying it.
- Soft spots and rot found when the old floor comes up.
- A new floor that needs it, such as tile over a subfloor that flexes; the tile installation cost guide prices the tile.
What moves the price
- Area. Small patches cost more per square foot than whole rooms.
- What’s on it. Toilets, vanities, cabinets and appliances come out and go back.
- The framing. Rotted joists are repaired or sistered before new panels go down.
- Where you live. Pick your state in the box above.
Common questions
How much does it cost to replace a subfloor?
$5.25 to $7.25 a sq ft in 3/4 inch tongue and groove plywood, with overhead, profit and sales tax.
How much is a bathroom subfloor?
About $300 to $425 for a 50 sq ft bathroom floor, typically $350, before the toilet and vanity come out and go back.
How much for a room?
About $775 to $1,050 for a 12 by 12 room.
Plywood or OSB for a subfloor?
Both are wood structural panels; pick by the span rating your joist spacing needs, from the code’s table.