Radon is a radioactive gas produced by uranium decaying in soil and bedrock. It seeps into houses through foundation cracks, sump pits, floor drains and service penetrations, and in a well-sealed home in a cold climate it accumulates. Health Canada identifies radon as the leading cause of lung cancer in people who have never smoked, and sets a guideline of 200 becquerels per cubic metre. Ottawa's geology places it among the higher-radon regions of the country, and there is no way to know a specific home's level except to measure it.
Long-term measurement is the honest test
Radon concentration swings enormously with weather, season, and whether a window was open. Health Canada recommends a minimum 91-day test during the heating season, because that is the only measurement that reflects what you are actually breathing over a year. That is the test we recommend and the one that should drive a mitigation decision.
The 48-hour screening test, and its limits
Real estate transactions do not wait 91 days. A short-term test using a continuous radon monitor under closed-building conditions can be completed inside a conditional period, and it is genuinely useful — a high short-term result is strong evidence, and a very low one is reassuring. But it is a screen, not a verdict, and we say so on the report rather than letting the number look more certain than it is.
If the level is high
Radon is one of the few serious home problems with a reliable, permanent, reasonably priced fix. Sub-slab depressurisation — a sealed pipe from beneath the basement floor to a fan above the roofline — typically costs $2,500 to $4,000 in Ottawa and routinely drops levels by 80 to 90 percent. We do not sell mitigation systems, which means we have no interest in your number coming back high.
What is included
- Placement and retrieval by a C-NRPP certified measurement professional
- Choice of 91-day long-term test or 48-hour continuous-monitor screening
- Closed-building condition protocol and documentation
- Written report with the measured level, the Health Canada guideline, and what it means
- Independent advice on mitigation — we do not sell or install mitigation systems
Why this matters in Ottawa
The Ottawa Valley's bedrock and glacial deposits are exactly the conditions that generate radon, and results across the city vary wildly street to street and even between neighbouring houses of the same age. A neighbour's low reading tells you nothing about yours. Take Action on Radon and Ottawa Public Health both run local awareness programs; the underlying advice is the same everywhere — test the actual house.