Subfloor Replacement Cost Per Square Foot
Eight hundred square feet of rotted plywood in a 1970s ranch prices out near $4,600 when the joists underneath are sound, and about $7,400 once two of them get sistered. The panels are roughly $1,500 of either number. The rest is tear-out, disposal and the joist work nobody sees once the floor is closed up.
Installed cost per square foot, by scope
Every bid here is two numbers stacked. Tear-out and disposal run $0.75 to $1.50 per sq ft over carpet or vinyl, and closer to $2.00 where thinset has to be chipped off tile. Panel, adhesive, screws and labor run $2.25 to $4.50. Anything under 100 sq ft picks up a $450 to $900 minimum, so a powder room patch reads $11 per sq ft on paper and $6 per sq ft inside a larger job.
| Scope | Typical area | Tear-out | Panel and labor | Installed per sq ft | Job total |
|---|---|---|---|---|---|
| Patch one soft spot | 40 sq ft | $60 | $390 | $9.00 - $14.00 | $450 - $900 |
| Re-sheet one room | 200 sq ft | $250 | $1,050 | $5.00 - $7.50 | $1,000 - $1,500 |
| Re-sheet a whole floor | 800 sq ft | $950 | $4,000 | $4.50 - $7.00 | $3,600 - $5,600 |
| Re-sheet plus two sistered joists | 800 sq ft | $1,200 | $5,400 | $6.50 - $10.00 | $5,200 - $8,000 |
| Bathroom over water damage, tile floor | 50 sq ft | $180 | $700 | $10.00 - $17.00 | $500 - $850 |
Those are national bands for 2026. A 23/32 in T&G sheet is $42 to $68 depending on region, and crews in the Northeast and coastal markets price installation 20 to 40 percent above the Midwest. The same 800 sq ft floor quotes at $3,600 in Ohio and $5,300 in Massachusetts.
The panel math behind the quote
A 4 by 8 sheet covers 32 sq ft. Waste runs about 5 percent, not the 10 percent a flooring carton needs, because offcuts from the last row go into closets and toe kicks instead of the trash.
Tongue-and-groove panels are the default on a floor. Square-edge panels need solid blocking at every seam, and that blocking costs more in labor than the T&G premium costs at the counter.
Plywood, OSB, or a coated panel
Bare OSB at $30 to $46 a sheet is the cheapest way to close a floor, and it is the panel that swells at a wet edge and stays swollen. Plywood at $42 to $68 holds a screw after a leak and takes a patch without crumbling. Coated OSB at $58 to $80 earns its price in a bathroom or a laundry room.
Five plies in a 23/32 in panel make a stiffer floor than four, and a core with visible voids will telegraph through vinyl and crack a grout line within two seasons.
What the inspector will look at
Panel thickness is set by joist spacing, not by what is in stock. IRC Table R503.2.1(1) allows 5/8 in over joists at 16 in on center and calls for 3/4 in at 24 in. Screws go 6 in apart on edges and 12 in in the field, and they have to bite into the joist.
Deflection decides whether tile belongs on top. Ceramic needs L/360 and stone needs L/720, and a floor that flexes under a heel will crack grout no matter how thick the panel. The Floor Joist Calculator checks a span against those limits before anyone buys a sheet.
Leave a 1/8 in gap between panels. Tight panels buckle into a ridge in August, and that ridge rocks every seam of a floating floor.
Two bids for the same 800 sq ft
Both crews will finish in three days. One is replacing a floor, the other is replacing a floor and fixing what ruined it.
| Line item | Bid A | Bid B |
|---|---|---|
| Panel | 7/16 in OSB, 25 sheets | 23/32 in T&G plywood, 27 sheets |
| Panel cost | $900 | $1,470 |
| Tear-out and haul-away | $600 | $960, includes tack strip and staples |
| Adhesive and screws | nails only | $140 |
| Joist repair | not listed | $1,600, two sisters at 12 ft |
| Floor prep and sanding seams | not listed | $420 |
| Labor | $2,300 | $2,850 |
| Total | $3,800 | $7,440 |
Bid A is not a scam. The 7/16 in panel meets code on 16 in centers, and a homeowner selling in two years can live with it. What it cannot do is carry tile, and the soft joist stays soft. Bid B costs $3,640 more and buys a floor that will not move.
What to buy
For an 800 sq ft main floor over joists that pass the deflection check, buy 23/32 in T&G plywood, glue it and screw it, and budget $4,600 to $5,200 installed with tear-out. A 5/8 in panel with floor leveler over it saves about $900 and gives up the stiffness that keeps tile flat.
Expect a finished floor about 3/4 in higher than the old one. That means door undercuts at $25 to $50 each, a toilet flange extension at $30 to $75, and a transition strip at every doorway. None of those lines appear in a per-square-foot price. The rest of the flooring estimators are on the flooring category page.