How to Remediate Radon

Back to Menu

Radon Part 2

Q: We just had our home tested for radon and the results have exceeded Health Canada guidelines. How did radon get inside our home and what can we do to lower the radon level?

A: First, let me congratulate you on getting your home tested for radon gas. A recent survey has reported the shocking results that less than 4 per cent of us have had our homes tested; which means that over 96 per of Canadians have not tested their homes for this cancer-causing gas! Health Canada and the Canadian Cancer Society have reported that over 16% of lung cancer deaths are caused by radon exposure, which makes radon the second-leading cause of lung cancer in Canada. That is why it is so important to remind folks that there is no such thing as a radon-free home and the only way to know if your home might be at risk is to have it tested.

Radon is a radioactive gas that occurs naturally from the breakdown of uranium in soils and rocks and is released every day from the earth into the outdoor air, where it is quickly diluted and is not a concern. However, radon is also the heaviest gas in nature so when it is released into enclosed living spaces, it can sometimes accumulate to elevated or high levels in the lowest level of a home, which also tend to be poorly ventilated. During the cooler winter months the air pressure inside our homes is lower than in the soil beneath our foundations and this difference in pressure will draw out any soil gases, including radon, from the earth into our homes which is sometimes referred to as a stack effect. Radon gas can enter our homes through any crack or gap in the basement floor or foundation walls, such as around service pipes, sump pumps, drains, etc.

Now that you know your radon results have exceeded the Health Canada guidelines you should hire the services of a C-NRPP Certified Radon Mitigation Professional, because they have been specifically trained to interpret radon test results, and can determine the most effective way to manage radon concentrations within your home. Canadian – National Radon Proficiency Program (C-NRPP) is a certification program designed to establish guidelines for training professionals in radon service and their website can direct you to a radon professional in your area.

The most effective and reliable method used by most C-NRPP professionals to reduce radon levels inside a building is a sub-slab depressurization (SSD) system. With this type of solution, a pipe is installed through the basement concrete floor and up to a specialized fan-powered vent, which is then directed to an exterior wall at ground level or up through the roof line. This system is designed to achieve a lower sub-slab air pressure relative to the indoor air pressure by drawing air from beneath the concrete foundation to the exterior of the home. The negative pressure under the foundations will draw any radon and other soil gases from below the concrete slab and pushes it to the outside before it can enter your home. This type of system may help reduce the radon level in a home by over 90%.  

So if you have friends, family or love ones who have not yet had their home tested for radon, please share this “Public Service Announcement” from Mike Holmes (PSA) and suggest they contact their local Lung Association or hardware store to purchase their own 91-day Radon test kit. 

Lawrence Englehart (Global Property Inspections) is a Registered Home Inspector and be reached at or or