Radon in Winnipeg homes: why winter is the time to test

November is Radon Action Month, when Health Canada encourages people to test their homes for radon [5]. In Winnipeg it's also the start of the season when a radon test tells you the most. Here's what the official sources say.

What radon is

Radon is a colourless, odourless radioactive gas that comes from uranium breaking down in soil and rock [1]. It can get into a house through cracks or gaps in the walls and foundation, and levels are generally highest in the basement [1]. Health Canada says radon is in every building in contact with the ground, it can vary widely even between homes on the same street, and testing is the only way to know a home's level [2].

Health Canada calls radon the leading cause of lung cancer for non-smokers in Canada [2].

Why Manitoba homes are worth testing

The Province says Manitoba has historically had higher radon levels in buildings than the national average. Health Canada estimated that about 19 per cent of Manitobans live in homes above the radon guideline, compared with about 7 per cent of Canadians, in a survey reported in 2012 [1].

Why winter is the time to test

Health Canada recommends testing for at least three months, ideally in winter, for example October to April, when indoor radon levels are generally highest [1]. Its guide asks that at least 91 days of the test fall in the heating season [2]. A heating-season test generally gives a conservative estimate of the yearly level [2]. Start in November and those 91 days fit well inside a Winnipeg winter.

How to run a test

Health Canada's steps for homeowners [4]:

Choose a long-term test kit, or an electronic radon monitor that has passed C-NRPP performance testing.
Place it on the lowest lived-in level of the home, such as a bedroom or finished basement, at breathing height.
Keep it out of kitchens, bathrooms, laundry rooms and closets, and away from windows, vents, heat sources and electronics.
Leave it in place for at least 3 months. With a kit, record the dates and return it to the lab as instructed.

You can also hire a certified radon measurement professional to do the test [6].

Winnipeg Public Library lends radon screening kits from November 1 to April 30 each year, for three weeks at a time, to anyone with a Winnipeg Public Library card in good standing [7]. The City says these kits are for short-term screening and don't replace the long-term test Health Canada recommends [7]. Use the 3-month test to decide.

What the result means

The Canadian guideline is 200 becquerels per cubic metre (Bq/m³), as a yearly average, in rooms where someone spends more than 4 hours a day [3]. If a home's level is above it, Health Canada recommends taking action to lower it within one year, and sooner the higher the level is [3]. Its brochure says to hire a C-NRPP certified radon mitigation professional to do it [4].

If you've just moved in

Health Canada recommends testing every home, including one that already has a mitigation system, when there's no recent result [2]. It also suggests testing again the next heating season after work that changes the structure or ventilation, such as a basement renovation or a new furnace [2].

For more winter upkeep, see Fall and winter home care in Winnipeg. If you're buying a home, what a home inspection report covers is a good companion read. If you're buying or selling this winter and want to talk it through, ask me.

Trevor LeVasseur, Licensed REALTOR® · Greg Michie Realty Group