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    The Open Door Blog


Whether you own a new home or condo, are considering buying one, or just love to dream about it, the Open Door blog is here to share stories that can help you protect what is likely the biggest investment of your life.

The Open Door blog is published by Tarion, a non-profit corporation that administers Ontario’s New Home Warranty Plan and registers all new home builders in Ontario. Click here to learn more about us.


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It’s Radon Action Month – What’s Radon You Ask?
November 24, 2016
It’s Radon Action Month – What’s Radon You Ask?

Playrooms, game rooms, family rooms, guest rooms, home gyms, laundry rooms – these are just a few of the ways today’s homeowners make great use of their basements. And, why not? Finished basements provide real value to your home investment. Plus, they can make life easier and more fun for everyone living within it.

Before you finish your basement or spend prolonged periods of time in it, Health Canada wants you to be aware of the potential for radon gas build up. Radon is an invisible, odourless, naturally occurring gas found in soil. It seeps into homes through cracks in floors, walls and foundations – access points mainly found in basements.


Radon is an invisible, odourless, naturally occurring gas found in soil. It seeps into homes through cracks in floors, walls and foundations – access points mainly found in basements.

Since radon is naturally occurring, it’s actually found in just about every home. There is no way to test for radon before building a home or predict where it may occur, because generally, open air levels of radon are too low to present a health risk. When radon is released into an enclosed space, like a basement, it can build up and that’s when there becomes a potential health risk. Health Canada says that people exposed to radon levels in excess of 200 Becquerels per cubic meter (Becquerels are a unit of measurement for radioactivity) over long periods of time have a higher risk of developing cancer.

Elliot’s Big Surprise

Elliot (not his real name) is a certified radon measurement provider. So it’s no surprise that he decided to test his three-year old home before finishing his basement. When he discovered he had high levels of radon in his home, he hired a certified radon mitigation contractor and had a mitigation system installed to reduce the radon concentration in his home.

It was only after the work was done that Elliot learned his new home warranty provides coverage for remediating excessive levels of radon. Elliot submitted a claim and then experts in environmental testing began a long-term test.

Before the three-month test could be performed with accuracy, Elliot shut off his previously installed mitigation system. Elliot and his family were safe to stay in their home during the test, but lab results did confirm the home’s high levels of radon. As a result, the warranty reimbursed Elliot for the work completed to install the mitigation system.

Is it time to test your home for radon?

Radon is found in almost every house in Canada, but concentration levels can vary even between neighbourhoods and even neighbours. Concentration levels can even change over time.

If you are concerned, there are two ways to test for radon: Buy a do-it-yourself radon testing kit or hire a radon measurement professional. Both options must be certified through the Canadian National Radon Proficiency Program to be eligible for coverage under the new home warranty.

Ontario is the only province where the builders’ warranty on new homes includes radon remediation coverage. The warranty covers remediation of radon gas in excess of 200 Becquerels per cubic metre and coverage lasts for up to seven years.

The warranty is intended to provide coverage from defects in materials or in the builder’s workmanship and while the presence of radon cannot be tested prior to construction nor is it caused by any type of defect in the home or workmanship, Tarion believes that radon remediation is an important part of consumer protection. We continue to work very closely with the new home building industry and municipalities throughout the province to monitor radon remediation in new homes and ensure that new home buyers are aware of the potential for radon build up and their warranty rights.

Lessons learned

  1. Every home has some level of radon, but Health Canada has set 200 Bq/m3 as the safety limit for radon levels in a home.
  2. Get to know your new home warranty rights before you take on work in your house, including efforts to mitigate excessive levels of radon. You can view Tarion’s information video on radon:

Do you have a story?

Share your story with us, so you can empower other homeowners to stay safe and healthy in their homes.

Additional Resources:

Remodeling: Cost vs. Value
Government of Canada Radon Guideline
Breathe, The Lung Association > Radon

The goal of this blog is to provide you with general information about the warranty process by sharing real experiences from new homeowners. The blog should not be relied upon as legal advice. For privacy reasons, we will not address or resolve current cases in a public forum, so any comments or questions that are posted on this site that describe individual cases cannot be discussed. If you have a question about your warranty or Tarion generally, we would be pleased to discuss your issue, in the context of your particular circumstances and in confidence. We exercise reasonable care to avoid offensive, illegal or defamatory content from being posted, as well as comments that are intended solely for self-promotion or considered to be spam.