Before I became a REALTOR®, I spent years as a home inspector. I could tell you a lot about a house from a walkthrough: how the roof was aging, whether the furnace had been looked after, where water was finding its way in. Radon was the exception. You can't see it, smell it or taste it, and nothing about a home's age, style or neighbourhood tells you whether it has a problem. The only way to know is to test.
The good news is that testing is simple, and right now is the best time of year to do it.
What radon is
Radon is a radioactive gas that forms naturally when uranium in soil and rock breaks down. Outdoors it disperses harmlessly. Indoors it can build up, entering through cracks in foundations, gaps around pipes, sump pits and floor drains. Health Canada calls radon the number one cause of lung cancer for non-smokers, which is why it's worth taking seriously even though it's easy to forget about.
Any home can have elevated radon: new or old, with or without a basement, in town or on an acreage. Two houses side by side can test very differently.
Why fall and winter are the best time to test
Health Canada recommends a long-term test lasting at least 91 days, or about three months, and says at least 91 days of the test should fall in the heating season. Its measurement guide describes October through April as the ideal window.
The reason is simple. In winter our windows and doors stay closed, and warm air rising through the house creates a slight draw at the foundation (the stack effect) that pulls more soil gas inside. Indoor radon levels are usually highest in the colder months, so a winter test gives you a conservative, realistic read on your yearly average. A test done in summer, with the windows open, risks underestimating it.
Start a test in early November and you'll have your results by spring.
How to test your home
Get a long-term test kit. Long-term detectors are small and easy to use, and you mail them to a lab when the test is done. Health Canada advises against relying on short tests of a few days to decide whether to fix anything, because radon levels swing from day to day.
Pick the right spot. Place the detector in the lowest lived-in level of the home, the area where someone spends a good part of the day, such as a finished basement, rec room or main-floor bedroom. Keep it away from drafts, heat sources, kitchens and bathrooms, and follow the kit's height and placement instructions.
Record the start date and leave it alone. Live normally. You don't need to change how you use the house during the test.
Mail it in after three months or more. Health Canada says results usually arrive within three to six weeks.
What your result means
The Canadian guideline is 200 becquerels per cubic metre (Bq/m³), based on your average annual level.
Below 200 Bq/m³: no action is needed under the guideline. Health Canada notes there's no level that's completely risk-free, so the rest is your call.
Above 200 Bq/m³: Health Canada recommends lowering it within one year.
Well above 200 Bq/m³: act sooner. The higher the number, the faster you should fix it.
What fixing it looks like
High radon is a very solvable problem. The most common fix is a sub-slab depressurization system: a pipe through the basement floor and a small fan that draws radon from beneath the slab and vents it outside. Sealing cracks and openings helps, but usually doesn't solve it on its own. Use a certified radon mitigation professional, and test again afterwards to confirm the level has come down.
Radon and buying or selling a home
Radon comes up more and more in real estate. A few practical notes from both sides of the table:
Sellers: a completed long-term test result, plus any mitigation receipts, is useful paperwork to have ready for buyers.
Buyers: a long-term test can't be done in the few days before an offer's conditions come off. If you want peace of mind, plan to test once you've moved in, and know that mitigation is a known, manageable fix.
Everyone: a short-term test can flag a concern, but Health Canada recommends basing decisions on a test of at least 91 days.
The bottom line
Radon testing is one of the cheapest, easiest things you can do for your home's long-term health, and the coming months are the right time to do it. Set the detector out in November, mark your calendar for February, and you'll know where you stand.
Have a question about radon, or anything else you've noticed in your home? Send us a message. We're happy to help, no strings attached.
Wayne & Sean Burton, REMAX West Real Estate, Cochrane, Alberta
Sources: Health Canada, Radon guideline; Guide for radon measurements in homes; Long-term test instructions; Should I test for radon?
