Radon and New Home Construction

Anyone preparing to buy a brand new house should be aware of new measures to deal with radon, an invisible, odourless soil gas that occurs naturally in areas across Canada.

The latest version of the National Building Code of Canada incorporates a number of measures to reduce radon in newly built homes. As provincial building codes adopt these, and they become law, all new homes in that province must meet these requirements.

In the meantime, radon-related requirements for new homes vary across the country, and there are areas where they do not exist. Some new home builders voluntarily adopt the new measures, particularly in locations known to have high levels of radon.

Why is it important to control radon in homes? While radon gas released from the soil exists in all air at very low concentrations, it is not a concern unless it builds up to higher levels inside a building. Then it can be harmful to people’s health, when they are exposed to it over a long period of time.

Although some regions in the country are more radon-prone than others, the gas can occur just about anywhere. Even in areas thought to be relatively radon-free, individual homes can still have higher than desired levels. The construction of a home as well as the lifestyle of the residents also have an impact—neighbours living side by side can have vastly different levels of radon in their homes.

Radon has been linked to lung cancer, and smokers in particular are vulnerable to its effects. In 2007, Health Canada recommended lowering the acceptable limit for radon in homes to bring it in line with international standards, and created new guidelines for dealing with radon in both new and existing homes.

When constructing a new home, builders can use a range of approaches, including installing an air barrier under the foundation slab and an airtight cover for the sump pit to prevent the entry of radon, and a rough-in for a possible future subfloor depressurization system, should radon problems emerge. Those are the measures now embedded in the National Building Code.

As a home buyer, your best approach is to talk with new home builders and find out about the building code requirements in your region and how they deal with radon control. It is important to recognize that there is no way to predict in advance if a home will have elevated radon levels, even with these measures in place.

Homebuyers should therefore test for radon once they move in to their new home. There are various do-it-yourself test kits available on the market, or you can hire someone to do it. The best and most reliable tests take time—several months or longer. If necessary, talk with your builder about further measures you can take, including an active depressurization system, to help reduce levels of radon and alleviate future problems.

There is a wealth of great information and advice available from a number of sources, including Health Canada and the Canadian Lung Association to help you learn more about radon and its effects, myths and facts, and how to test for it in your own home. Provincial governments may also have helpful information.

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