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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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How often should you test your home for radon?
November 14, 2018
Door Opening

Radon can make its way into any home – regardless of whether it is old or new, big or small – the invisible, odourless gas can still seep in. This is why everyone should regularly monitor their home to ensure that radon levels are safe.

Do You Know About Radon?
   Click to view full-size.

But this raises the question – how often should you test for radon in your home? Well, to put it this way – how often do you go for health-related check-ups? Similar to your dental or medical check-ups, radon testing should be conducted regularly at least twice a year.

Like people, no two houses are the same. Radon levels can also vary between neighbours, so don’t rely on their results to determine whether or not to test for radon.

Like people, no two houses are the same. Radon levels can also vary between neighbours, so don’t rely on their results to determine whether or not to test for radon.

Can radon levels change over time?

Yes, radon levels can fluctuate from year to year or even throughout the year based on a number of factors:

  1. Seasonal Effects – Seasonal changes can cause radon concentration levels to vary within your home. Tarion and Health Canada recommend testing for radon between October and April and using the 3-month test. If testing is performed during the summer, consider conducting another test in the fall or winter season. With the changing temperature levels, the weather and air pressure can produce different readings during certain periods. For example, having windows open more often during the summer months can often skew test results.
  2. Home Modifications – When major renovations are done in your home, this can affect the ventilation and soil beneath your house, thereby creating new opportunities and routes for radon to enter your home. The gas can pass in through cracks in the walls or foundation, construction joints, and gaps in the floor or service pipes.

If you are planning any structural modifications, such as turning your basement into a living space, it is important to test for radon before beginning renovations. You should also have your home retested after the renovations are complete to determine whether your radon levels have changed.

  1. Changes in Living Patterns – If you decide to start using the basement as a workspace, bedroom or a play room for the kids, it means that you’ll be spending more time in the areas where radon is most likely to accumulate. Regularly monitoring radon levels in this area will ensure that making use of this space is not putting your health at risk.

Ontario is the only jurisdiction in Canada where the builders’ warranty on new homes includes radon remediation coverage. The warranty covers remediation to reduce radon levels if radon gas in your home is in excess of 200 becquerels per cubic metre and coverage lasts for up to seven years.

Tarion continues to work very closely with the new home building industry and municipalities throughout the province to ensure that new home buyers are aware of the potential risks associated with radon build up and the warranty coverage available.

To learn more about radon, we encourage you to watch our video, Radon and Your New Home Warranty and you can visit the Health Canada website. If you are looking for do-it-yourself radon test kits or for a radon measurement or mitigation professional, you can contact the Canadian National Radon Proficiency Program by visiting www.c-nrpp.ca.

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.