Radon Testing & Mitigation near you

Radon moves from the soil into any part of a house that touches the ground. Health Canada notes it can be found in almost all Canadian homes, and because it can't be seen or smelled, a dry, well-kept basement tells you nothing about its level. Your neighbour's result is no substitute for testing your own home.

The Canadian guideline is 200 becquerels per cubic metre (Bq/m³). Health Canada recommends a long-term test lasting at least 3 months, and its measurement guide calls for at least 91 days of the test to take place during the heating season.

Put the detector on the lowest level where someone spends more than four hours a day, follow the kit's instructions and leave it in place for the whole test. When the result comes back above the guideline, Health Canada recommends acting to lower it, and the higher the level, the sooner.

Health Canada lists two ways to test: buy a do-it-yourself long-term kit, or hire a radon measurement professional. The Canadian National Radon Proficiency Program (C-NRPP) trains and certifies radon measurement and mitigation professionals and offers an online tool to find one nearby. Health Canada's Take Action on Radon page also points homeowners to long-term kits sold online and to certified professionals.

Health Canada's reduction guide describes active sub-slab depressurization as the most effective and reliable technique, and the most common one used by C-NRPP certified professionals. A pipe is installed through the basement floor slab and connected to a fan that runs continuously, drawing radon from beneath the house and releasing it outdoors, where it quickly dilutes.

Other measures play a supporting role. Sealing cracks and openings can help, but the guide says it isn't a standalone technique, since every opening is hard to locate, reach and close for good. A sump can be capped and sealed so it keeps draining water while serving as the suction point, and a heat recovery ventilator brings in outdoor air, which the guide says might reduce radon by 25 to 50 per cent in most homes.

Only a new measurement proves a system works. Health Canada's reduction guide recommends a short-term test by a C-NRPP certified professional, started at least 24 hours after the fan is turned on, followed by a long-term three-month test the next fall and winter to confirm the annual average is below the guideline.

According to Health Canada's reduction guide, the 2010 National Building Code requires every building to have granular fill under the slab and a rough-in for a future radon reduction system, so one can be completed if testing shows the need. Provinces adopt the national code on their own schedule, so ask your builder or municipality what applies where you live. A rough-in doesn't lower radon until it is connected to a working fan, and a new home still needs its own long-term test once it's lived in.