FRBathroom ceiling patch, Ottawa
8 sq ft of surface mold on painted drywall, from condensation.
$500 to $1,100, typical $800, before tax.
At this size Health Canada says you can usually clean it yourself. Run the fan longer first.
Mold Removal Cost Calculator for Canada (2026 Prices)
A number online won't replace a quote. It will tell you whether the quote in your hand makes sense.
By Andrey Golubev, senior inspector and remediation supervisor Last updated: November 5, 2026
Most mold removal jobs in Ontario and Quebec cost $1,500 to $15,000 before tax, and standard jobs usually land at $2,500 to $7,000. A patch under 10 square feet can cost as little as $500, and a whole house starts near $15,000 and can pass $35,000. How much surface is affected and how deep the mold went set the price. Its colour doesn't. If you're guessing from a stain, or holding one quote with nothing to compare it to, the calculator below gives you a rough range, a first step and the questions to ask. Every number here is a rough guide and not a price for your home: only an inspection can give you a real one.
Estimate your mold removal cost
Three short groups of questions. The rough estimate updates as you go, and we don't ask for your email.
What mold removal costs by size and depth
Rough planning ranges, not quotes. Before tax, one area, normal access, at Canada's average prices. An attic costs about 40% less because the roof deck is open and unfinished.
| Affected surface | On the surface | Soaked into material | Hidden or unknown | Structure damaged |
|---|---|---|---|---|
| Under 10 sq ft | $500 to $1,100 | $800 to $1,500 | $1,000 to $1,900 | $1,300 to $2,300 |
| 10 to 30 sq ft | $1,500 to $2,700 | $2,100 to $3,500 | $2,500 to $4,300 | $3,100 to $5,100 |
| 30 to 100 sq ft | $2,500 to $4,600 | $3,600 to $6,000 | $4,300 to $7,400 | $5,300 to $8,800 |
| 100 to 300 sq ft | $4,000 to $7,000 | $5,500 to $9,000 | $6,500 to $11,000 | $8,000 to $13,000 |
| 300 to 1,000 sq ft | $7,000 to $11,800 | $9,400 to $15,000 | $11,000 to $18,200 | $13,400 to $21,400 |
| Over 1,000 sq ft | $15,000 to $27,000 | $21,000 to $35,000 | $25,000 to $43,000 | $31,000 to $51,000 |
Small jobs cost more per square foot because setup, containment and cleanup barely shrink with the job. Ottawa's PatchBoyz lists $14 to $25 per square foot for 30 to 100 square feet, and $9 to $14 past 100.
| Where the home is | Compared with the national average | Sales tax we add |
|---|---|---|
| Toronto and the GTA | 15% above | 13% HST |
| Ottawa area | 2% above | 13% HST |
| Gatineau and the Outaouais | 2% above | 14.975% GST and QST |
| Montreal, Laval and elsewhere in Quebec | 5% below | 14.975% GST and QST |
| Kingston, Cornwall, Brockville, Belleville | 6% below | 13% HST |
But how far the mold went matters more than where it is
The same 60 square feet can be a cleaning job or a demolition job. Non-porous surfaces can be cleaned. Health Canada says drywall with mold under the paint has to be removed and replaced. Hidden mold costs the most to price, because nobody knows where it stops until the wall is open.
People ask what colour the mold is, and it barely moves the price. What moves it is whether we can clean the surface or have to take the wall out.
Fix the water first, or you'll pay for the same job twice.
Myth Black mold always costs more to remove.
Fact Health Canada ties risk to the extent of growth, regardless of the species. Some companies charge 10% to 30% more for black mold, according to Masters' Guild. Ask what the extra pays for.
Myth You need an air test to find out what the job costs.
Fact Health Canada doesn't recommend routine air testing. For visible mold, a look at the affected area usually sets the scope. An air test earns its $550 when the problem can't be explained.
So check what the quote covers before you compare prices
Two quotes can be thousands apart because one of them stops earlier. Our estimates are good for 60 days, and removal jobs take a 40% deposit before work starts. Some inspection fees can be credited if you go ahead with removal.
In our removal quote
- Containment and HEPA air cleaning
- Removing and disposing of contaminated material
- Cleaning the affected area
- Clearance testing: lab air sampling or on-site swab tests, depending on the job
Budget for these separately
- Rebuilding walls, floors and insulation
- Fixing the leak, the humidity or the air leaks behind the mold
- Asbestos abatement, if a test finds it
- Duct and HVAC cleaning, which we don't offer
We don't rebuild in-house. In some areas we can refer you to a partner, who quotes separately. These are published Canadian rates to budget with:
| Rebuild item | Installed price | Source |
|---|---|---|
| Drywall, installed and finished | $1 to $4 per sq ft | RenoQuotes, Soumission Rénovation |
| Basement wall insulation | $2 to $6 per sq ft | RenoQuotes |
| Attic insulation, whole attic | $1,500 to $3,000 | HomeStars |
| Air sealing and attic ventilation | $350 to $1,500 | HomeStars |
| Carpet, installed | $4.50 to $12.50 per sq ft | RenoQuotes |
| Most new flooring, installed | $5 to $12 per sq ft | RenoQuotes |
| Structural wood repair | $3,000 to $10,000 | Soumissions Après Sinistre |
Three mold removal estimates, worked through
Made-up homes to show the method, not real customer jobs or real prices. A real home with the same answers can cost very different amounts.
Finished basement wall, Mississauga
60 sq ft soaked into drywall from a slow leak, in a home built before 1990.
$4,100 to $6,900, typical $5,400, or about $6,102 with HST.
Add $430 for the first asbestos sample and $500 to $1,000 to rebuild. Insurance is unlikely to pay for a slow leak.
Attic roof deck, Montreal
600 sq ft of surface mold from condensation, and the insulation has to come out.
$4,500 to $8,100, typical $6,100, or about $7,014 with GST and QST.
Add $1,500 to $3,000 for new insulation, and seal the air leaks so it doesn't grow back.
How we built this calculator, and where it falls short
Every price below is public. The judgment calls are ours, and we've listed them.
| Source | What we used | Date and place |
|---|---|---|
| Our own team's price ranges | $1,500 to $2,500 for 10 to 100 sq ft; $2,500 to $7,000 for 100 to 300; $7,000 to $15,000 for 300 to 1,000; $15,000 to $35,000+ for a whole house | Price list, November 2026 |
| Soumissions Après Sinistre | $500 to $1,200 under 10 sq ft; $1,200 to $3,000 for 10 to 50; $3,000 to $6,000 for 50 to 100; $6,000 to $15,000+ over 100 | Quebec, 2025 |
| Soumission Rénovation | $1,500 to $2,500 under 10 sq ft; $2,500 to $5,500 for 10 to 100; $6,000 to $10,000+ over 100 | Quebec, July 2026 |
| DKI Central Alberta | $500 to $1,500 under 10 sq ft; $1,500 to $3,500 for 10 to 30; $3,500 to $6,000 for 30 to 100; $6,000 to $10,000+ over 100 | Alberta, 2026 |
| Masters' Guild | $500 to $1,500 under 10 sq ft; $10 to $25 per sq ft; attic $2,000 to $6,000; basement $1,500 to $5,000 | Canada, July 2026 |
| PatchBoyz | $9 to $14 per sq ft over 100 sq ft; $14 to $25 for 30 to 100; attic $1,500 to $8,000 | Ottawa, October 2026 |
| CostCanada | City gaps to the national average: Toronto +15%, Vancouver +20%, Calgary +5%, Ottawa +2%, Montreal -5%, Kingston -6%, Halifax -8% | City guides, 2026 |
| HomeStars | Attic insulation $1,500 to $3,000 installed | Canada, August 2026 |
| RenoQuotes | Drywall $1 to $4 per sq ft; basement wall insulation from $2 per sq ft; rigid foam up to $6 | Canada, 2024 to 2026 |
| Health Canada | Size classes, when a professional is needed, risk regardless of species, air testing | Published January 2023 |
| Canada Revenue Agency | GST/HST and provincial tax rates by province | April 2025 |
| Quebec government | Asbestos products mainly used from 1930 to 1990; vermiculite marketed from 1920 to 1990 | January 2021 |
How the sum works
We set each size band where our team's ranges and the Canadian guides overlap. Depth then places the job inside that band, or past it for hidden and structural work. Next come the area, access and regional adjustments, and the result rounds to the nearest $100. Several areas add together, with no discount for sharing a visit.
Our judgment calls
These numbers are our own estimates and no source publishes them: where each depth sits inside a band, 15% for hard access, 40% off for an attic, and the typical job at 45% of the way up the range. Most sources are contractor or quote sites without a stated method, and only CostCanada gives the city gaps.
Mold removal cost questions
How accurate is this mold removal cost calculator?
It gives a planning range, not a quote. Nobody can price hidden mold from a form, and the same 60 square feet can cost twice as much once a wall is opened. Use the range to set a budget and to check a quote you already have. A real price needs someone to look at the home.
Can I clean the mold myself instead of paying for removal?
Often, if the area is small. Health Canada says a professional generally isn't required for three or fewer patches totalling under 1 square metre, about 10 square feet, with the right precautions. It says a qualified professional is needed for a single patch over 3 square metres, for hidden mold, and for mold that keeps coming back.
Does black mold cost more to remove?
Not because of its colour. Health Canada says the level of risk depends on the extent of mold growth, regardless of the species, and it doesn't change the cleanup by colour. Containment and material removal drive the price, so this calculator has no colour question. Some companies do charge more for black mold, so ask what the extra pays for.
What does a mold removal quote include?
Ours covers containment, HEPA air cleaning, removing and disposing of contaminated material, cleaning the area and a clearance test: lab air sampling or on-site swab tests, depending on the job. Clearance testing is included in your quote. Rebuilding walls, new insulation and fixing the moisture source are separate.
Does home insurance pay for mold removal in Canada?
Sometimes. RBC Insurance says mold is typically covered when it comes from a sudden, accidental covered peril like a burst pipe, but not from gradual, preventable moisture. Sonnet says its policy might cover mold from a covered event, with no guarantee. OTIP notes that policies may set limits. Check your own policy before you count on it.
Who pays for mold removal in a rental?
Usually the landlord, unless the tenant caused the damage. In Ontario, section 20 of the Residential Tenancies Act makes the landlord responsible for keeping a unit in a good state of repair. In Quebec, the Civil Code requires the lessor to keep the dwelling in good habitable condition. Tribunals decide disputes, so keep photos and dated messages.
Do I need an air test before mold removal?
Not usually. Health Canada doesn't recommend testing the air for mold as a routine step, and it favours a careful visual inspection. It makes room for an air test when a problem can't be explained, especially after leaks into wall cavities. That's when we'd suggest our air test, at $550 before tax, and we'll say so when you don't need one.
A range tells you what to expect. A look tells you what it costs.
Send us your estimate and a few photos. We'll reply within one business day, and if it's a job you can do yourself, we'll tell you.