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Mold RemediationMold Cost Per Square Foot: Pro Rates by Area Type and Severity
Quotes only compare on a per-square-foot basis. Find your area type and severity in the rate chart below, then enter that rate here with your affected square footage — a fast sanity check on any mold remediation cost per square foot you have been quoted.
Mold work is quoted at roughly $10–$30 per square foot of affected area. Ordinary surface growth in an accessible finished room sits at $10–$22; basements run $20–$30; black mold and HVAC contamination, where full containment is standard, run $25–$35. Below about 30 sq ft the rate stops mattering, because a $500–$1,000 minimum charge takes over.
How this calculator works
This is deliberately a straight area × rate multiplication with nothing added, because that mirrors exactly how a contractor builds the per-square-foot line on a quote. Use it the other way round too: divide a quoted total by your affected square footage and see where the implied rate falls in the chart below. Two bids only compare if they measured the same area and included the same scope, so the chart lists what each severity band normally covers.
What changes the number
- A published per-square-foot rate normally covers labor, containment, HEPA cleaning, bagging, and disposal — not demolition, rebuild, or the moisture repair.
- Most firms carry a $500–$1,000 minimum, so on jobs under about 30 sq ft the effective rate per square foot is far higher than any chart.
- Black mold and HVAC contamination are never priced as a surface-only clean; containment is standard on both, which is why those rows start higher.
- Ask whether the quoted rate includes the post-remediation clearance test — an independent test is usually $250–$700 on top.
- Rates are regional. Dense metro markets sit above these national ranges and rural markets below, so compare at least two local quotes before deciding a rate is high.
- Contractors price the area they must contain and cut back, which usually extends a foot or two past the visible patch — expect their measured area to exceed yours.
Mold rates per square foot by area type and severity
| Where the mold is | Surface only ($/sq ft) | Into materials ($/sq ft) | Full containment ($/sq ft) |
|---|---|---|---|
| Finished room — drywall, trim, closet | $10–$14 | $14–$22 | $22–$30 |
| Bathroom — tile, grout, subfloor | $10–$15 | $15–$22 | $22–$30 |
| Attic roof deck | $12–$14 | $14–$18 | $18–$20 |
| Crawl space | $15–$18 | $18–$22 | $22–$25 |
| Basement | $20–$23 | $23–$27 | $27–$30 |
| HVAC ducts, coil, air handler | Not priced this way | $25–$30 | $30–$35 |
| Black mold (Stachybotrys), any location | Not priced this way | $25–$30 | $30–$35 |
| Whole house / multiple rooms | $15–$20 | $20–$25 | $25–$30 |
Frequently asked questions
What is a normal mold remediation cost per square foot?
$10–$30 per square foot covers most residential jobs. Surface growth in an accessible finished room sits at the bottom of that band; basements, crawl spaces, black mold, and HVAC contamination sit at the top, and containment-heavy work reaches $35.
Is mold priced per square foot or per job?
Both, depending on size. Small jobs are quoted as a flat price against the firm’s minimum, usually $500–$1,000. Larger contiguous areas get a per-square-foot rate. Ask which basis a quote uses before comparing two bids — a flat $800 for 20 sq ft and a $22/sq ft rate are not the same pricing model.
How do I measure the affected square footage?
Measure the contiguous growth: length × height for a wall, length × width for a floor or ceiling. Then expect the contractor’s figure to be larger — they price the area they have to contain, cut back, and clear, which typically extends one to two feet beyond visible growth.
Does the per-square-foot rate include fixing the leak?
No. The moisture source — a leaking pipe, a roof, foundation seepage, or poor ventilation — is a separate trade and a separate invoice. It is also the repair that decides whether you pay for the mold work once or twice.
Why is my quote so much higher than area times rate?
Minimum charges; containment setup and negative-air rental that cost the same whether the area is 40 or 400 sq ft; the $250–$700 clearance test; and demolition or rebuild quoted separately. For a full-scope figure rather than the bare rate, use the mold remediation cost calculator.