What You Should Know About Radon In Your Home

What You Should Know About Radon In Your Home

What You Should Know About Radon In Your Home Oct 2017

From Your Friends At GoldEye Home Inspection

What do you know about Radon? For most people, the answer is not much. You should though. You’re breathing it every day and, depending on your home, it could be raising your risk of lung cancer.

Here are some facts. Studies have shown that Radon is the second leading cause of lung cancer, behind smoking. Southern Ontario (including Guelph, Kitchener, Waterloo, and Cambridge) is known to have high soil levels of radon gas. Health Canada has recently performed a national survey of Radon in homes and a high percentage of homes (well above the national average) with elevated radon levels have been found in this area. Do I have your attention yet? Okay, let’s dial down the alarm level for a minute and talk about what Radon really is and why you should be aware of it.

Radon is a colorless, odorless gas that is formed by the radioactive decay of Uranium. It’s in soil and it’s in the air we breathe. Since the outside air we breathe is mixed and diluted with regular air, the radon is in very low concentrations. And since radon is a gas, we breathe it in and out and it doesn’t pose a great risk to us. That’s when we’re outside.

Here’s where I have to use a little technical language and talk about radioactivity. Radon is, like the uranium it comes from, radioactive. That means that at some point each atom of Radon will “decay” by shooting out a little particle and the Radon atom will become an atom of something else- depending on the makeup of particle it shoots out. You really don’t need to know the details of this. What is important to know is:

1) Depending on the makeup of the particle released, it is the “thing” from radioactive substances that can damage your DNA and cause cancer. Your body can often repair this damaged DNA or remove cells with damaged DNA. It’s typically not a situation where the first time you get a bit of DNA damage, you’ll get cancer. But the more of the radioactivity you’re exposed to, and the longer you remain exposed, the greater the risk that your body won’t be able to keep up with the repairs and cancer will develop.

2) While Radon is itself a gas, the substances produced by the decay of Radon are all solid and are all still radioactive (they shoot out particles too).

Here’s why it’s important to know what the radon levels in your home are. First of all, if the radon levels are high, the number of those particles flying around are increased (ie. you’re exposed to more radioactivity). But the second point is perhaps more important. The more radon that enters your home, the more of the solid decay products that develop. And they can build up over time. They attach to surfaces in your home or dust particles in the air. If you breathe them in, unlike Radon, they tend to stay in your lungs and that’s where the risk of increased lung cancer really comes from.

How does Radon get into the house? Radon formed in the soil can seep up into the house through every tiny crack or crevice in the basement or crawl space. Basically, anything that is in contact with the soil has to be perfectly sealed or Radon will get in. Then in areas of the house with poor air movement (typical basement or crawl space areas) the Radon can build up.

So what should you do? Well, a first good step is to find out if the Radon levels in your home are high. Radon is measured in Becquerel/m3. Health Canada recommends that you take measures to reduce your Radon levels if those levels are above 200 Becquerel/m3. Reducing exposure further is a good practice in any case, but what action you take may be based on the levels that are measured.

In a home, the radon is trapped and can’t dissipate like it would outside. Diluting the Radon with fresh air will reduce the Radon level somewhat, so good ventilation, especially in basements and crawl spaces is a first step. The second approach is to provide good air filtration to remove the decay particle dust and prevent it from getting into your lungs. If your Radon levels are near, but below the 200 Becquerel/m3 limit, these steps may be effective in reducing the Radon to a safer level.

But the gold standard is to prevent the radon from getting into the house in the first place. New construction techniques add a vapor barrier under the slab and/or around the foundation where it meets soil (this may or may not be done in your area). Radon Mitigation companies will typically install perforated pipes under the basement or crawl space slab and connect it to what is essentially a vacuum pump to pump air out and up into the atmosphere. Since this creates a lower pressure under the slab than in the house, the air under the slab will not seep into the house. But this can be expensive if they have to break up part of the slab to bury the pipes.

In new construction, a “rough-in” of the pipes under the slab may be required, which makes installation of the pump system easier if Radon levels are found to be elevated later. And there’s more good news. If your home is covered by the Tarion New Home Warranty, Radon Mitigation is covered if it is shown that Radon levels are elevated. But the levels must be measured by a Canadian National Radon Proficiency Program (C-NRPP) certified professional.

That’s another important point. You can buy Radon measurement kits at your local hardware store. But it’s very important that the units are placed in the right location in the home, and the measurement is performed for the right period of time. Radon can vary with changes in the home. For example, doors and windows may stay open more in summer, allowing more air flow. People may stay indoors more at certain times of the year. The weather can even have an effect on Radon levels. That’s why Health Canada recommends Radon tests be performed for at least 90 days and preferably during the winter months.


As a home inspector in the Guelph, Kitchener, Waterloo, Cambridge area, we are usually asked to perform an inspection on a home that is in the midst of a real estate transaction. Everything is happening very quickly so we don’t have 90 days to provide a client with an accurate Radon measurement. But there are measurement methods that can be used for as little as 48 hours. Typically, we would deploy our detectors two days earlier to obtain a 48-hour result on the day of the inspection. They will give you a good snapshot of the Radon levels at that time, but we always recommend that a full 90-day test be done as a follow up to confirm high or low Radon levels.

If you’d like to learn more about Radon, here are some links that you might find useful.

Canadian – National Radon Proficiency Program (C-NRPP)

Info on Radon Gas by Tarion

Radon Info By The Government of Canada

Radon Info by the City of Guelph

Region of Waterloo Radon Info

Radon: What You Need To Know – Region of Waterloo

And if you’d like to read more articles like this on other aspects of homes or Home Inspections, please check out our blog

Steve Schroeder

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