Since 1 November 2015, every new Alberta home with a foundation in contact with soil has had to include a radon rough-in. That single date splits the housing stock into two groups with very different repair costs.
The Alberta Building Code 2014, in force from 1 November 2015, requires new homes with a foundation in contact with the ground to be built with a rough-in for a subfloor depressurization system. In practice that means four things:
This is the part that gets misread, in both directions.
The rough-in does not reduce radon. It is a capped pipe doing nothing. A house built in 2020 to code can still test high, and plenty do.
What the rough-in does is make the fix straightforward. Instead of coring the basement floor and running new pipe through a finished house, a certified mitigator connects a fan and a vent to what is already there.
Two houses, same reading, very different jobs:
| Built | What mitigation involves |
|---|---|
| After November 2015 | Connect a fan and vent to the existing rough-in. Shorter job, less disruption, lower cost. |
| Before November 2015 | The full installation. Core the slab, run new pipe through the house, seal entry points, fit the fan. |
The build year is on the listing. It is knowable before an offer, before an inspection, and before anyone spends anything.
That does not make a newer house safe and an older house dangerous. It makes the same radon result a smaller problem in one and a larger one in the other, and it lets both sides price the condition sensibly instead of guessing.
Check the build year first. On a pre-2015 house, radon is worth raising as a condition, because if the number comes back high you are looking at a full installation. On a post-2015 house it is a smaller line item.
Either way, the rough-in tells you nothing about the actual level in the house. Only a test does that.
If your house is post-2015, the rough-in is worth mentioning, because it turns a buyer's open-ended worry into a known, bounded job.
If your house is pre-2015 and you have already mitigated, that is worth more than saying nothing. A documented system with a confirming re-test removes the question entirely, and it is one of the few home improvements that is genuinely finished when it is finished.
This is the part that gets flattened in most write-ups, including ours before we corrected it. The National Building Code is a model code. It does not apply anywhere by itself. Each province and territory adopts it on its own timeline, and several amend it. So the year that splits the housing stock is different depending on where you are, and in one large province the requirement does not apply everywhere at all.
The radon rough-in with a stub was added to the National Building Code in 2010. What provinces did with it varies:
| Province | Position |
|---|---|
| Alberta | Alberta Building Code 2014, in force 1 November 2015. Rough-in required in new homes with a foundation in contact with soil. This is the version described above. |
| British Columbia | Under the BC Building Code 2024, a rough-in for a subfloor depressurization system is required province-wide, without exception, for Part 9 buildings. Earlier BC codes applied it to designated areas only, so the BC split year is not the same as Alberta's. |
| Ontario | Different in kind, not just in date. The Ontario Building Code 2017, with Supplementary Standard SB-9, gives builders three options for radon protection, and applies in areas of Ontario with known radon problems rather than everywhere. An Ontario buyer cannot assume a post-2017 house has a rough-in. |
| Saskatchewan and Manitoba | Both follow the National Building Code, which carries the radon provisions. The specific requirement level varies and is worth checking against the code edition in force when the house was permitted. |
| Everywhere else | We have not verified the adoption date or the scope for Quebec, the Atlantic provinces or the territories, and we are not going to guess at them. If you are in one of those, ask your provincial building authority which code edition applied when the house was built. |
The practical rule: the build year only tells you something once you know which code applied where the house stands, and whether it applied to that particular location. In Alberta that is straightforward. In Ontario it is not.
No. A rough-in is a capped pipe with no fan attached, and it does nothing to radon levels on its own. It exists so that a mitigation system can be added easily if a test shows one is needed. A new house built to code can still test high.
Look for a capped pipe stub coming up through the basement floor slab, usually near a wall, sometimes labelled. Build year is the quicker check: in Alberta, homes permitted after 1 November 2015 should have one.
Generally yes, because the pipe and the sub-slab aggregate are already in place and the work becomes a connection rather than an installation. How much less depends on the house, so get quotes either way.
That is a decision for you and your agent, and the build year is a reasonable input. On a pre-2015 house a high result means a full installation, which is a bigger number to negotiate over. Bear in mind that a proper long-term test takes months, so what usually gets used in a live transaction is a short-term test with its limitations understood.
Sources. Health Canada radon guidance and published measurement data; the 2024 Cross-Canada Survey of Radon; World Health Organization Handbook on Indoor Radon; United States Environmental Protection Agency; Canadian National Radon Proficiency Program. Costs described are general ranges, not quotes.