Why Alberta in particular
Radon is a naturally occurring radioactive gas produced by the decay of uranium in soil and rock. It seeps into buildings through foundation cracks, sump pits, floor drains, service penetrations and gaps around plumbing, then accumulates in enclosed lower levels where there is not enough air exchange to disperse it.
Health Canada identifies radon as the leading cause of lung cancer among people who have never smoked, and sets a guideline of 200 becquerels per cubic metre for indoor air. Above that level, remedial action is recommended.
Alberta consistently records higher residential radon concentrations than the Canadian average, and Calgary is not an exception within that. The prairie geology and construction patterns both contribute. What matters practically is that a meaningful share of Alberta homes exceed the guideline and the overwhelming majority of homes have never been tested.
Your neighbour’s result tells you nothing about your house
This is the single most misunderstood thing about radon. Concentrations vary enormously between adjacent properties, because the result depends on the specific geology under that foundation, the condition and detailing of that foundation, how that building is ventilated, and the pressure differentials that particular house generates when its heating runs.
Two houses built by the same builder in the same year on the same street can differ by a factor of several. A neighbourhood average is a curiosity. Only a measurement inside your building means anything about your building.
What a proper test involves
Health Canada recommends a long-term test of at least three months, conducted during the heating season, when windows are closed and the building is operating in its normal winter state. The reason is variability: radon levels swing substantially day to day with weather, pressure and how the building is being used, so a short-term snapshot can be misleading in either direction.
The device is placed in the lowest level of the home that is used regularly — a finished basement counts, an unfinished crawlspace generally does not — away from drafts, exterior walls, windows and heat sources. It then sits undisturbed for the duration.
At the end of the period the device is retrieved and sent for analysis, and a certified professional interprets the result against the guideline.
- Minimum three months, per Health Canada guidance
- Conducted during the heating season
- Placed in the lowest regularly used level
- Left undisturbed for the whole period
- Analysed and interpreted by a certified professional
Who should do it
Measurement and interpretation should be carried out by a professional certified under the Canadian National Radon Proficiency Program (C-NRPP). Certification matters here more than in most trades, because both the placement of the device and the interpretation of the number affect whether the result means anything.
VacantHomes.ca does not measure radon, does not interpret results and holds no radon certification. Where testing is wanted on a property we monitor, we coordinate the engagement, attend for placement and retrieval, and confirm during routine visits that the device has not been moved or disturbed.
If the result is above the guideline
It is a solvable problem, which is worth saying clearly because the word "radioactive" produces more alarm than the remedy warrants. Mitigation is a well-established technique — most commonly sub-slab depressurisation, which uses a pipe and a small continuously running fan to draw soil gas from beneath the foundation and vent it above the roofline before it can enter the building.
Properly installed systems routinely reduce concentrations substantially, and the work is typically completed in a day. Alberta’s building code has required a radon rough-in in new residential construction for over a decade, which makes mitigation simpler in newer homes.
Mitigation should be designed and installed by a C-NRPP-certified mitigation professional, and the property should be retested afterwards to confirm the system is doing what it was designed to do.