Replacing a plywood subfloor costs $3 to $8 per square foot installed in 2026, with most residential projects falling between $4 and $6 per square foot. For a 300 sq ft room, that’s $1,200 to $1,800. Material alone runs $2.50–$3.50 per square foot for standard 3/4-inch CDX plywood; labor adds $25–$45 per hour depending on your market.
Those numbers assume you already know the subfloor needs replacing. Most homeowners don’t. Subfloor damage hides under finished flooring for years, and it typically surfaces at the worst possible moment: a contractor pulls up old carpet or tile and finds rot, or the bathroom floor starts feeling spongy around the toilet. Suddenly you’re making a $1,500 decision with a crew standing by.
What Subfloor Replacement Costs by Room
Room size drives total cost, but complexity matters just as much. A bedroom with no plumbing is fast work. A kitchen with cabinets and appliances is a different job entirely.
| Room | Typical Area | Cost Range | Why It Varies |
|---|---|---|---|
| Bedroom | 100–150 sq ft | $400–$700 | Simple geometry, no plumbing, easy access |
| Living room | 200–350 sq ft | $600–$1,800 | Larger area but usually uncomplicated |
| Bathroom | 35–75 sq ft | $500–$750 | Toilet removal, plumbing penetrations, likely joist damage from water |
| Kitchen | 100–175 sq ft | $800–$2,500 | Cabinets may need removal, appliance disconnection, often multiple problem areas |
| Whole house | 1,500–1,800 sq ft | $6,000–$14,000 | Economies of scale on labor, but material volume adds up fast |
Bathrooms cost more per square foot than any other room because the damage is rarely limited to the plywood. Water from a failed wax ring or slow supply-line leak seeps into joists and framing. By the time the floor feels soft, the structure below has been wet for months.
Materials: Plywood vs. OSB vs. High-Performance Panels
The subfloor material you choose affects both the upfront cost and how long the repair lasts, especially if moisture was the original problem.
| Material | Installed Cost/Sq Ft | Moisture Resistance | Best For |
|---|---|---|---|
| CDX plywood (3/4") | $2.75–$6 | Moderate — handles incidental moisture | Standard replacement in bedrooms, living rooms |
| OSB | $3–$4.40 | Poor — swells permanently when wet | Dry areas only; avoid in bathrooms |
| AdvanTech | $4.75–$9.25 | Excellent — backed by 500-day no-sanding guarantee | Bathrooms, kitchens, anywhere moisture caused the original failure |
| DriCore | $4.65–$8.85 | Built-in moisture barrier | Basement subfloors over concrete |
The material decision most people get wrong: OSB is tempting because the sheets run $10–$20 less than comparable plywood. But OSB absorbs water like a sponge, and once it swells, it never goes flat again. If moisture caused the subfloor failure in the first place, installing OSB is recycling the same problem. Spend the extra $0.50–$1.00 per square foot on plywood.
In bathrooms, AdvanTech is worth the premium. Paying $2 more per square foot now prevents paying $6 per square foot for the same replacement in a decade.
Thickness matters: use 3/4-inch plywood for joists spaced 16 inches on center, which is most residential construction. 5/8-inch works on 12-inch spacing but flexes noticeably underfoot on wider spans, and tile installed over a flexing subfloor will crack within two years.
Labor Cost Breakdown
Labor for subfloor replacement runs $25 to $45 per hour, with most contractors quoting by the project rather than hourly. A two-person crew on a 300 sq ft room typically bills 8–12 hours of combined labor.
What that labor covers, broken down for a 300 sq ft project:
| Task | Estimated Cost | Notes |
|---|---|---|
| Demolition of old subfloor | $350–$500 | Includes pulling up finished flooring if still attached |
| Hauling and disposal | $50–$150 | Dumpster rental or dump fees; rotted wood often requires separate handling |
| Joist inspection and prep | $100–$200 | Cleaning joist tops, adding blocking where needed |
| New plywood installation | $250–$400 | Cutting, fitting, gluing, and screwing panels |
| Fasteners and adhesive | $75–$125 | Construction adhesive + screws (not nails — screws pull the plywood tight and don’t back out) |
| Total labor and supplies | $825–$1,375 | Materials (plywood sheets) billed separately |
The detail contractors don’t always explain: the old plywood comes out in pieces, not sheets. Rotted plywood breaks apart during removal, and the remaining nails in every joist need pulling before new panels can sit flat. On a badly deteriorated floor, demolition alone takes longer than installation.
Repair vs. Full Replacement
Not every soft spot means tearing up the whole floor. The decision between patching and full replacement depends on how far the damage has spread.
Partial repair makes sense when:
- Damage is confined to one or two spots (around a toilet, under a window, near an exterior door)
- The rest of the subfloor passes the screwdriver test (push a flathead into the wood; it should resist penetration)
- Total damaged area is under 30–40% of the room
- Cost: $1–$3 per square foot for the affected section, typically $200–$600 per patch
Full replacement is the answer when:
- Rot extends across multiple panels or along joist lines
- The floor bounces when walking across the center of the room, not just near edges
- Mold is visible on the underside (partial patches leave contaminated wood in place)
- The subfloor is original OSB from a 1990s build and has absorbed repeated moisture
Patching means cutting the damaged section back to the center of the nearest joist on each side, so the new piece has solid bearing to screw into. Cut between joists and the seam has nothing to rest on. This is the single most common DIY mistake: patching a 2x3 foot section when the joists are 16 inches apart, leaving a seam floating in mid-span. That seam flexes underfoot and telegraphs through any hard flooring above it.
What Drives the Cost Up
Standard replacement in a bedroom is the low end of the price range. Several factors push the number past $8 per square foot — and sometimes well above it.
Joist damage is the biggest escalator. If water or termites reached the joists beneath the subfloor, replacing the plywood is only half the job. Sistering a new joist alongside a damaged one costs $125–$315 per joist. A bathroom with four damaged joists adds $500–$1,200 to the project.
If the subfloor rotted from a long-term leak, assume the joists need inspection at minimum.
Active mold adds $1,500–$4,000 for remediation before a single panel can go in. The EPA recommends professional remediation for coverage beyond 10 square feet, and most jurisdictions require licensed contractors before new materials go in. If you smell mildew when the old floor comes up, stop work and get an assessment first.
Two labor inflators hit kitchens, bathrooms, and upper floors especially hard. In kitchens and bathrooms, disconnecting a gas range, pulling a toilet, or working around fixed cabinets adds hours — some contractors quote cabinet removal as a separate line item at $200–$500 per run. On a second story, every sheet of plywood goes up a staircase and every bag of debris comes back down, plus the ceiling below needs protection from fastener penetration. Expect 15–25% more than the same job on a ground-floor slab.
Signs Your Subfloor Needs Attention
Subfloor failure announces itself gradually, and most homeowners adapt to the symptoms without realizing what they mean. The flooring signs guide covers the full range of damage indicators across flooring types. The list below focuses specifically on what points to subfloor failure rather than surface-level wear, ranked by urgency:
- Spongy or bouncy spots when walking — the plywood has delaminated or rotted between joists. This is the most reliable indicator and means replacement, not repair.
- Tiles cracking or popping loose without impact — the substrate underneath is moving. Tile needs a rigid, flat surface. If the subfloor flexes even slightly, thinset bond fails and grout cracks. This is worth checking before any tile installation project .
- Musty smell from below the finished floor. That’s wet wood and mold underneath, sometimes noticeable only in humid weather or when the HVAC is running.
- A toilet that rocks despite tight flange bolts. The wood beneath the flange has softened, which is bathroom-specific and almost always means the wax ring has been leaking.
- Cupped or buckling hardwood — moisture is pushing up from below. The hardwood itself may be salvageable, but the subfloor underneath likely isn’t. Subfloor failure from chronic moisture is one of the triggers for early hardwood floor replacement .
The screwdriver test takes 30 seconds: push a flathead screwdriver into any suspect area. Sound wood resists firmly. If the tip sinks more than 1/4 inch with hand pressure alone, that section is compromised. Tap adjacent areas with the handle and listen — solid wood gives a dull thud, rotted wood sounds hollow.
DIY Subfloor Replacement: When It Works
Subfloor replacement is a moderate DIY project — harder than laying laminate, easier than framing a wall. The tools are basic: circular saw, drill, pry bar, chalk line.
DIY works well for:
- Single-room bedroom or closet with no plumbing and visible joists from below. You’ll save $2–$4 per square foot in labor.
- Partial patches where the damage is clearly defined and the surrounding subfloor is solid.
Hire a professional when:
- Joist damage is present or suspected. Sistering joists requires understanding load paths and often needs a permit.
- The room has plumbing. Cutting near drain lines without hitting them requires experience and a mistake tolerance most homeowners don’t want.
When hiring for subfloor work, getting written itemized bids matters more than almost any other flooring project because hidden damage is the norm. The flooring hiring guide explains what to include in a scope of work and how to evaluate bids that vary widely before any wood comes up.
A 150 sq ft bedroom runs $375–$675 in materials versus $600–$1,200 professionally installed — that’s a real saving, but only if no hidden joist damage turns up mid-job.
One critical DIY detail: use construction adhesive (PL Premium or similar) on every joist before screwing panels down. Screws alone eventually allow micro-movement that causes squeaking. Adhesive creates a permanent bond.
Use #8 or #10 coarse-thread screws every 6 inches along joists, not nails. Nails back out over time as wood cycles through humidity changes, and that backing-out is exactly what causes squeaking in the floor you’re replacing.
Finished Flooring on Top: Budget for the Full Stack
New plywood is rarely the end of the project. You chose to replace it because something failed, and now new finished flooring goes on top. Budget for the full stack:
| Finished Flooring | Additional Cost/Sq Ft | Combined with Subfloor |
|---|---|---|
| Laminate | $3–$8 | $6–$14/sq ft total |
| Luxury vinyl plank | $4–$10 | $7–$16/sq ft total |
| Tile | $7–$15 | $10–$21/sq ft total |
| Solid hardwood | $12–$22 | $15–$28/sq ft total |
These ranges come from installed costs in the flooring cost guide . A 50 sq ft bathroom getting new subfloor ($500–$750 from the table above) plus tile ($350–$750 at $7–$15/sq ft) runs $850–$1,500 total, not counting joist repair.
The timing advantage of combining projects: if a contractor is already in there with the floor open, adding subfloor replacement to a flooring project costs less than doing it as a standalone job. Demo is already done, joists are already exposed, and mobilization costs are shared. Getting a separate quote for subfloor work after the floor is back down means paying for two rounds of tearout.
New plywood subfloor needs to acclimate to the room’s humidity for 48–72 hours before finished flooring goes on top, especially if the room had a moisture problem. Stacking sheets flat with spacers between them lets air circulate.
Skip this step and the plywood adjusts after installation, potentially warping the finished floor above it. The flooring process guide covers the full installation sequence from subfloor through finished surface.