Radon Precautions Information

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  • Information

    BCFSA’s information is clear, concise, easy-to-read explanations of the requirements for real estate professionals under the Real Estate Services Act (“RESA”), Real Estate Services Regulation (“Regulation”), Real Estate Services Rules (“Rules”), and other applicable legislation.

    This information is intended for use by real estate professionals, to support their understanding of the standards they must meet in the delivery of real estate services.

Issued: July 30, 2020

What is Radon?

Radon is a naturally occurring, radioactive, odourless, and colourless gas that is generated through soil minerals. It is created through the decay of radium, thorium, and uranium-bearing bedrock and soil and is released into the atmosphere as it rises to the surface of the earth. Because radon is a gas, it can move easily through the soil and cracks in bedrock to reach the air. Generally, it then dissipates into the atmosphere causing no harm. However, if radon seeps indoors it can accumulate to dangerously high levels. The radiation emitted by radon is absorbed by your lungs and has been identified by Health Canada as the second leading cause of lung cancer behind smoking. Among non-smokers, radon exposure is the leading cause of lung cancer. Radon is measured in becquerels (“Bq”) and is expressed in units of Bq/m³ (becquerels per cubic metre). Becquerels are units used by scientists to measure the number of radioactive decay events taking place over time. Radon damage is caused by the radioactive alpha particles (α-particles) it emits. These alpha particles can ultimately damage DNA in both humans and animals if they are exposed to high concentrations over time.

Radon Graphic

Radon Gas in B.C.

Uranium is found in the ground across the country and radon can also be found in almost all homes across Canada. High concentrations of radon are typically found where there are higher levels of uranium in underlying rock and soil including the Prairie provinces and parts of B.C. In B.C., higher levels can be seen along the mountains that border Alberta and along the western coast of the province.

Figure 1 (below) shows the prevalence of radon in B.C. Zone 1 represents the highest levels of radon in the province while zone 3 is the lowest.

Radon BC Map

Radon as a Material Latent Defect

The Government of Canada’s Radon Guideline indicates that if radon levels are above 200 Bq/m³, remedial measures should be undertaken to mitigate the health risks to the property occupants. A material latent defect is created where levels of radon gas in homes or buildings exceed 200 Bq/m³. A number of homes and buildings in B.C. have levels of radon gas in excess of 200 Bq/m³.

As a real estate professional representing a seller or landlord, you must disclose to all parties to a trade any material latent defect that is known to you, before any agreement for a purchase or lease is entered into, such as radon levels that exceed 200 Bq/m3. If you are representing a buyer or tenant, the Rules require that you use reasonable efforts to discover relevant facts respecting any property your client is considering acquiring, as part of your obligations to your client.

How Radon Enters a Home or Office

Health Canada, Evict Radon, and the Government of B.C. have all provided information outlining how radon can impact residential and office spaces. Below are facts complied from those sources. For more detailed information please visit Health Canada About Radon, and Evict Radon.

Air pressure inside a residential or commercial property is typically lower than the pressure in the surrounding soil at the property’s foundation. This is especially true in the fall and winter months (October through April) when properties are sealed up to reduce heat loss. The pressure differential can be exacerbated by bathroom vents, clothes dryers, and the fact that more air is usually expelled from a home than is drawn in from the outside.

When the differential gets too high, air is pulled up through the ground and into the property through gaps and cracks in the foundation. This air often contains varying levels of radon. The larger a property is, the larger the foundation footprint is. The larger the foundation, the greater the chance of radon seeping in becomes.

  1. Single-family Homes
    In a single-family home, or semi-detached or attached townhome, radon levels will typically accumulate in the lowest level. Testing will show higher concentrations in basements versus the main or upper level of the home as the basement foundation floor is where radon will typically enter the premises.
  2. Multi-storey Buildings
    In multi-family dwellings (such as condo towers), and commercial buildings, radon will also typically affect those occupying spaces below grade or at ground level more than those who occupy space on upper levels. Sometimes, however, it is the upper units which experience higher levels of radon. This is known as the “stack effect”. Because warm air rises, it can draw air up through elevator shafts and stairwells allowing radon gas to accumulate on the higher floors.

    Mitigation efforts such as venting parkade air and adjusting HVAC systems can often reduce the stack effect.

Understand Radon Testing

Health Canada, Evict Radon, and the Government of BC have information outlining how to test for and remediate radon in both residential and office spaces on their website. Below are facts complied from those sources. For more detailed information, please visit Health Canada About Radon, and Evict Radon.

1. How To Test
Because radon levels can fluctuate over short periods of time, and change from one season to the next, long-term detectors are the recommended form of testing. Longer term tests last from one month to a year and are most accurate when used between October and April. Health Canada recommends that property owners only purchase Canadian National Radon Proficiency Program (“C-NRPP”) approved long-term radon measurement devices. Radon test kids must meet Health Canada Guidelines.

The most common type of long-term tracker in Canada is the alpha tracker. These can be purchased at most hardware stores, online, and from radon detection and mitigation services. They are simple to set up, do not require any power to operate, and once the testing period has ended, can be mailed back to the manufacturer who will provide you with a report indicating the levels of radon in the property.

image of radon alpha tracker

Other long-term testing options include electret ion chambers and continuous radon monitors.

Some property owners may also prefer to work with a professional to test for radon. In Canada, radon testing and remediation companies must be certified through the C-NRPP. To find a radon tester or mitigation expert in your area, visit C-NRPP Find a Professional.

While there are currently no regulations for radon testing in Canada, Health Canada only recognizes the validity of long-term alpha track detectors and long-term electret ion chambers in determining if a home has high radon levels or not. Short-term measurements are not acceptable to determine radon concentrations for the purpose of assessing remediation needs. Health Canada suggests that any results from a short-term test be followed up with a long-term measurement at the same location.

2. Where To Test
According to Evict Radon, testing for radon should be done in the lowest property level which is occupied for four or more hours a day. In taller buildings such as residential and commercial strata complexes, testing should be done on each occupied floor.

Health Canada’s “Guide for Radon Measurements in Residential Dwellings” states that testing sites should occur near an interior wall at a height of 0.8 to two metres from the floor, at least 50 centimetres from the ceiling and 20 centimetres from other objects so that normal airflow may occur around the testing device.

You should avoid testing in bathrooms, closets, near sump holes or crawl spaces as those are not areas typically occupied for extended periods of time. You should also avoid testing in locations with strong air currents such as near windows, vents, and fans. Some testing devices may also be negatively affected by heated areas such as near fireplaces, heaters, or in direct sunlight.

3. Understanding the Results
If a long-term test result is less than 200 Bq/m³, no further measurements are necessary. While the risks from radon below that threshold are low, Health Canada states that there is no safe level of radon. Mitigation is always an option regardless of the testing level.

If the results are higher than 200 Bq/m³, Health Canada recommends remediation. For levels greater than 600 Bq/m³, it is recommended that remediation occur in less than a year. Between 200 Bq/m³ and 600 Bq/m³, remediation is recommended in less than two years.

Effective Radon Mitigation

Health Canada, Evict Radon, and the Government of BC information outlining how radon can be remediated in residential and office spaces on their website. Below are facts complied from those sources. For more detailed information please visit Health Canada About Radon, and Evict Radon.

There are many types of mitigation that can eliminate radon concentrations or vent high levels of radon gas that may be present. Sealing around drains, sump pumps, and cracks in the floor and walls is an effective first step to try and reduce the amount of gas entering the home.

The most common, effective, and reliable mitigation method is known as sub-slab depressurization. This technique employs a pipe with a fan attached that is installed through the foundation floor and connected to the outside through and exterior wall or up through the roof. The system can reverse air pressure differences and vent radon gas before it accumulates in the home.

Homes with a crawl space may need to use other methods such as sub-membrane depressurization. Consult with a radon remediation specialist to determine the most effective method for your client’s property type.

Once full remediation has been successful, radon levels can be reduced by up to 90 per cent. Follow up testing should be done every five years.