Mold Inspection & Air-Quality Testing

Mould in a house is a moisture problem first. An inspection looks for where the water is coming from, such as a leaking supply line, a wet basement wall, condensation on cold surfaces, a bathroom without a working fan or a roof leak into the attic, and then measures how much mould has grown and on what.

Health Canada sizes the problem in three bands: small is one to three patches each under one square metre, medium is more than three patches or a patch between one and three square metres, and extensive is any patch larger than three square metres. Those bands drive the advice on who should do the cleanup.

Be careful with air testing. Alberta Health Services says air testing for mould is usually not recommended, especially if you can already see it, and Health Canada's guideline states that results from tests for fungi in air cannot be used to assess risks to the health of occupants. There is no numerical mould exposure limit in Canada. Air sampling has a place when mould is suspected behind a wall or in a duct and nothing is visible, or when a buyer or an insurer wants a documented baseline, but it is not the first step, and no inspector should promise a health verdict from it.

Published Calgary-area prices for a mould inspection or air-quality test run about $200 to $800 depending on the size of the house and how many samples are taken. Ask what the inspector will actually look for, whether moisture readings and photos are in the report, and whether the same company would be quoting the remediation, which is worth knowing before you read their findings.