Mold and air quality testing in Longueuil

Longueuil gets about 4,275 heating degree-days a year and has a winter design temperature of −23.2°C, according to NRCan's HOT2000 climate data for Montréal-St-Hubert. On cold days, exterior corners, closets on outside walls and window frames get cold enough for condensation, which is where mold usually starts in Longueuil houses.

Of Longueuil's 52,710 houses (single-detached, semi-detached, row houses and duplexes), 21% were built before 1961 and 76% before 1991, according to the 2021 Census. Older basements without a moisture barrier and houses that were air-sealed without adding ventilation are common trouble spots.

• You smell mustiness but can't find the source.
• After a leak or flood, to check that cleanup worked.
• Before buying an older house with signs of past water damage.

If you can see mould, you usually don't need a test to know it's there; you need to fix the moisture and clean it up properly.

Quebec has a voluntary standard for handling mould in homes (BNQ 3009-600, 2020); no province has a mandatory residential mould standard.

Ask any Longueuil tester which lab analyzes their samples, and look for one accredited under AIHA's EMLAP program for environmental microbiology. Pair sampling with a ventilation and humidity assessment, which finds the cause.

Ventilation and humidity assessments in Longueuil · Our mold and indoor air quality guide