Worried About Radon Gas?


This guide has been created to give a simple overview for any homeowner who is concerned about the issue of radon in the home. It is by no means comprehensive and does not replace advise you may seek from a qualified radon expert.

At the end of this guide there are links to more detailed information and organisations you can approach for professional advice and radon testing.

What is radon?

It’s a gas by-product of the breakdown of natural radioactive minerals in the bedrock and soil like uranium. While levels vary, even from one house to the next, radon emission is a common occurrence throughout the North American continent (and other areas around the world). So you can’t assume that because your neighbour’s house is radon free your’s is too.

What are the health risks?

Without getting all technical it’s not the gas as such (as most of this is exhaled) but the radioactive decay products it emits as it continues to decay that cause carcinogenic damage to cell nuclei in the body. Lung Cancer Canada attributes some 3,200 deaths in Canada to exposure to radon. The second highest single cause of lung cancer after smoking.

Should I be concerned about radon in my home?

If the level is above 200 Bq/m³ (becquerels per cubic metre) then, according to Health Canada’s guidelines, you should. And a study published by the University of Calgary in 2017 estimates that 1 in 8 home in Calgary have a level of radon that exceeds this level. But let’s also remember that this is a guideline only. Do we now consider there is a safe number of cigarettes to smoke? And ‘safe’ level guidelines vary around the world. But what does all this mean?

How does radon enter my home?

If there is radon being emitted from the ground below and around your property then it can enter via small holes, cracks, plumbing penetration and poorly sealed sump pits - see diagram below. There is evidence that even the concrete slab is not fully impermeable. These would account for most, if not all, of the sources. 

Radon can also be carried in water, especially if you have a well that is in radon emitting ground - but this would be <5% of the source. The gas is released when the water is agitated by a shower or faucet aerator.



So, how do I know if there is radon in my home?

Radon is a colourless, odourless, tasteless gas, so the only way is to test for it. Fortunately testing can be very simple and inexpensive - but here’s a very important warning - RADON LEVELS VARY SIGNIFICANTLY OVER TIME. 

You can buy a test kit that contains a sampling device that you deploy for a couple of days or so then you send this to a lab (often for an additional fee - but still inexpensive). In a couple of weeks you get the results.

But wait, if radon levels vary significantly over time how do you know the resulting level is a true reflection of the average radon levels in your house? You don’t!

The best ways to test for radon

Based on the research of the author (and this is, of course, just a personal opinion) you need to use a test kit or testing service that monitors radon levels over a minimum of 3 months for accurate results.

Some people like to install a permanent monitoring system even if the initial test they do shows average levels below the ‘safe’ level of 200 Bq/m³. For a few hundred dollars you have on-going peace of mind.

Whether you choose a DIY kit from a home improvement store or the internet, or you prefer to have the input of a professional tester, who can help interpret the results, is a purely personal choice.

It is suggested though that if you use a professional testing service you ensure it is that organisation’s key field of experience and something they do regularly as this will ensure you get the best help in reviewing the results and on what to do if radon levels are high in your home.

You can perhaps now appreciate why it’s not really practical to do a radon test during the home purchase process.

What if you find you have a radon issue? 

Well, it’s a relatively easy fix. In financial terms you’re probably looking at $2000 to $2500 - the price of a new fridge!

In simplistic terms, one or more holes (as appropriate) are drilled through the basement slab to access the soil area below. Pipework - think toilet waste pipe - is sealed into the hole and fed up through the roof (again just like your toilet vent pipe). Obviously, the pipework would be concealed in the walls of any living space.

The radon gas below the slab is release via this vent pipe into the atmosphere. Often an in-line exhaust fan is fitted in the attic to help suck out the offending gas.

Any holes, cracks, etc. around the basement would be appropriately sealed

Where do I go for further advice?

You are welcome to contact Brooks Home Inspections for free, impartial advice - just click on the Contact tab above.

Graeme Brooks is a Certified Home Inspector based in Calgary. As such he is a generalist in the various areas of residential home construction and not an expert in the field of radon in the home but he has researched the topic extensively and is happy to share what he has learnt. He does not offer radon testing or mitigation services.

You can also get more information from the following sources - just click on the links:

If you wish to buy a test kit, monitor or contact a radon professional then click on the following link. Just remember to ask about someone’s level of experience to get the best help: