How to eliminate or prevent the entry of radon

How do you get rid of radon in a home?

If radon tests in your home show radon levels below 200Bq/m³, there is no cause for concern. However, if the radon concentration is between 200Bq/m³ and 600Bq/m³, you should take corrective measures within two years, or sooner if the radon level exceeds 600 Bq/m3. 

Depending on the characteristics of your home and the radon levels detected, the necessary corrective measures can vary, as can the cost, which can range from a few hundred to a few thousand dollars. They include: 

• Sealing cracks in the concrete of foundation walls and floor slabs 
• Sealing gaps around utility connections such as pipes and ducts in foundation walls or floor slabs 
• If there is no concrete slab, covering the crawl space floor with a polyethylene membrane (minimum 3/1000 of an inch), commonly called a vapour barrier, and sealing the joints and edges 
• Sealing openings at the top of concrete block walls with mortar or expanding foam 
• Installing traps in the floor drains that allow water to drain, but prevent radon infiltration 
• Sealing open sumps 
• Installing more efficient ventilation in the basement, and possibly throughout the rest of the house, including an air exchanger 

In cases where radon concentrations are very high, it may be necessary to install a depressurization system to remove radon trapped under the floor slab. This is an exhaust vent that runs through the floor slab to the outside of the house. The radon is then drawn in by a fan and expelled outside. This technique is more invasive and obviously more expensive, but it generally allows radon concentrations to be reduced by about 95%. 

Find the right specialist for your work

Be sure to choose a qualified radon mitigation contractor who has the tools needed to perform multiple simultaneous measurements in larger buildings. Mitigation specialists can analyze your situation and recommend solutions, and handle or supervise the mitigation work in accordance with the protocol and standards established by the Canadian National Radon Proficiency Program (C-NRPP) and the National Radon Safety Board (NRSB).i Find a mitigation specialist: 

• CAA-Quebec Approved Residential Suppliers 
• Canadian National Radon Proficiency Program 
• Canadian Association of Radon Scientists and Technologists 
• Health Canada 

Want more information on radon or need to find a mitigation specialist? Contact a professional from our Advisory Services. 

How do you prevent radon from infiltrating a new home?

Obviously, it is difficult to predict the potential radon levels in a home before the home has even been built. 

However, there are some simple measures that can reduce the risk of future infiltration, such as: 

• Installing a flexible mastic sealant between the floor slab and the foundation walls 
• Installing a waterproof polyethylene membrane under the concrete 
• Installing a drainpipe under the concrete slab, which can later be connected to a depressurization system if necessary 
• Installing an adequate ventilation system 

Most of these measures will only add a few hundred dollars to the total cost of construction, so why not go ahead and be proactive?