Get In touch Today: (519) 742-1114 | [email protected]
  About Us Services Blogs Radon Thermal Imaging Faq Contact 

Property Condition Assessments, Home Inspections, Radon Testing and Mitigation,
Thermal Imaging,
Indoor Air Quality Testing

Get In Touch


Radon Awareness and Tarion's Radon Gas Warranty Coverage


Over the last few years, exposure to radon gas as a potential concernfor new home buyers has recieved heightened media attention. Health Canada issued a report in 2012 -- suggesting that up to 16% of lung cancer cases could be attributed to long term exposure to radon gas. 

Tarion clarified the impact that radon gas issues would have on a home's warranty coverage. If radon gas is found in a home in significant amounts, it will be covered by tarion. To assist Tarion employees in making consistant warranty descisions related to radon gas, a guideline has been developed when dealing with the potential radon-related claims. The reported defect must be that Radon Gas is in excess of Health Canada's acceptable levels of 200Bq/m3, in order for it to be covered by Tarion. These guidelines account for the Ontario Building Code requirements for Radon and soil gas contral.

Warranty Coverage for Radon Claims

1st year: fit for habitation (if radon levels are >200 Bq/m3)

                OBC Violations (if the home is not in compliance with,, and Radon levels are >200 Bq/m3


2nd year:  OBC Health and Safety (if the home is not in compliance with,, or, and Radon levels >200 Bq/m3)


Years 3-7  MSD coverage (if the home is not in compliance with,, or, and Radon levels 200 Bq/m3


A valid Radon claim could potentially be covered by the first year warranty, under the "fit for habitation" criteria or if the home is not in compliance with the OBC guidelines. It could also be potentially covered by the second year warranty if the home does not meet the OBC guidelines. In addition, given the heightened awareness of the potential risks posed by the radon contamination, a claim could fall within the definatition of a Major Structural Defect should the problem be considered one that renders the home uninhabitable.


What Warranty Limits Apply to Radon Claims

Claims that involve radon are limited in the following ways:

  1. Costs incured to substantiate a radon claim are not covered
  2. Personal injury / health issues caused by Radon are not covered
  3. Damage to personal property is not covered

In addition Radon claims paid by Tarion are limited by a financial cap. The financial cap on Radon related claims is set out as follows.


"... the maximum amount payable (...) for damage caused by environmentally harmful substances or hazards, deleterious substances, mould or any other fungal or bacteria contamination, is $15,000.00 per home"


The limit will apply to repairs to remediate a radon problem carried out by Tarion.

In order fro a Radon claim to be accepted, the home owner must provide the following supporting materials:

  1. Test results identifying average radon levels in basment (finished or unfinished, but not from crawl spaces)
  2. Identification of test mothodology (short term test: less than 3 months, or long term test: minimum of 3 months as per Health Canada's Guide for Radon Measurements in Residential Dwellings (Homes) 
  3. Test measurement results from a certified professional by the Canadian National Proficiency Program (C-NRPP)

If the above information indicates average Radon levels > 200 Bq/m3 as indicated in a short-term test, then further investigation is required in the form of a long term test.

If the above information indicates average radon levels >200 Bq/m3 as indicated in a long-term test, then the information is deemed acceptable and the case may proceed to remediation.


The bulletin was put out by Tarion.

Home owners in most cases through conversation I have found out do not have knowledge of this information from their builders. 








Subscribe to this Blog Like on Facebook Tweet this! Share on LinkedIn


Tom Weber
October 13, 2017
show Tom's posts

Latest Posts

Show All Recent Posts



CAHPI OAHI Medallion Solutions RespirCare