What does professional mold remediation involve in a Calgary basement?

For a medium basement mould job (more than three patches or a patch between one and three square metres), published Calgary-area prices read in September 2026 run roughly $1,800 to $6,000; a large job covering a whole basement can reach $3,000 to $15,000 or more. The size of the affected area, the materials involved and how far the moisture source has spread are the main things that move the number.

Here is what a professional remediation typically involves, and what to look for at each step.

What the work covers

A contractor starts by finding and stopping the moisture source, because without that, mould returns. They then contain the affected area to keep spores from spreading to the rest of the house, remove porous materials such as drywall, carpet and ceiling tiles (Alberta Health Services says these typically need to come out, not just be cleaned), clean non-porous surfaces, and dry the space thoroughly. Health Canada advises keeping relative humidity between 30 and 50 per cent.

The asbestos question

If your basement was built or finished before 1990, raise the asbestos question before any drywall, ceiling tile or flooring is disturbed. The Alberta OHS Code requires a contractor to encapsulate, enclose or remove materials that may release asbestos fibres before renovation work proceeds in that area. A bulk sample test runs $65 to $145 per sample at published Calgary-area lab prices. That is a small cost compared to the complications of discovering asbestos mid-job.

What a fair quote includes

Ask that the written quote spell out:

• How the containment will be set up and removed
• Which materials will be removed versus cleaned
• Whether disposal of debris is included (the City has no specific rule for mould debris, so confirm how waste will be handled)
• Whether a post-remediation air quality check is included or quoted separately (roughly $200 to $800 for an inspection or air test)
• The completion date and total price

Alberta Health Services notes that air testing for mould is usually not recommended when you can already see it; paying for air sampling before remediation, when the problem is visible, is generally not a useful spend.

Consumer protection

If the contractor asks for any payment before the work is finished, they are operating as a prepaid contracting business and must be licensed with Service Alberta. A prepaid contract of $200 or more must be in writing and include names and addresses, a detailed description of the work, itemized prices, the completion date and your cancellation rights. You can check a contractor's status through Service Alberta's licensed-business search. Also ask for a WCB clearance letter confirming the contractor has an account in good standing; without one, you could be liable for unpaid premiums.

There is no Alberta licence or government certification for mould remediation, and no City of Calgary permit for this work. The Alberta OHS Code does require that where mould exists or may exist, the employer control worker exposure through the hierarchy of controls, but that obligation runs to the contractor's workers, not to you.

Start with a contractor rather than the municipality or Alberta OHS, because the first practical step is getting eyes on the moisture source and the extent of the damage; a site visit will tell you whether the job is medium or large, whether asbestos testing is needed first, and what a realistic scope of work looks like before any money changes hands.