Reducing Radon (Radon Mitigation)
What do I do after I test my home and get my results?
The Canadian guideline for radon in indoor air is 200 Bq/m3.
If you’ve tested your home, and the Radon concentration is above the Canadian guideline of 200 Bq/m3, Health Canada recommends that you take action to lower the concentrations. The higher the Radon concentrations, the sooner action should be taken to reduce levels to as low as practically possible.
While the health risk from Radon exposure below the Canadian guideline is small, there is no level that is considered risk free. It is the choice of each homeowner to decide what level of Radon exposure they are willing to accept.
How do I reduce Radon concentrations in my home?
Health Canada recommends that homeowners consult with a Radon professional certified by the Canadian National Radon Proficiency Program (C-NRPP) to determine the best Radon reduction method.
The effectiveness of any one Radon-reduction method will depend upon the unique characteristics of a home, the concentration of Radon, how it’s getting into a house or building and how thoroughly the job is done. A single method may do the job but sometimes, a combination of several methods must be used.
Radon-reduction methods include:
Active soil depressurization (or sub-slab depressurization)
- A pipe with a fan attached, is installed through the foundation floor and connected to the outside through an exterior wall or up through the roof. This system draws the radon from below the house to the outside to stop it from entering the home.
- This is the most common method of Radon reduction when large reductions are necessary.
- Can reduce the Radon concentrations in a home by over 90%.
- Costs range from about $2500 – $3000 including material and labour. There is also a small operating cost for electricity for the fan (approx. $50-$75 per year depending on the size of fan and energy rates)
- Must be installed by a C-NRPP-certified Radon Reduction Professional.
Sealing major entry routes for Radon
- such as open sumps, floor drains, floor wall joints, exposed soil, voids in concrete block walls and foundation wall and floor cracks.
- Sealing cracks and other openings in the foundation is a basic part of Radon reduction and can help increase their effectiveness. Proper preparation of the surface area to be sealed in very important to create an effective and long-lasting seal.
- Costs of sealing entry routes can range from a few hundred dollars to $2000 or more.
- Material costs are low but it is very labour-intensive and as the house ages and settles, the seals can deteriorate and new cracks or entry routs can appear.
Increasing mechanical ventilation of the home with heat recovery ventilator (HRV)
- The effectiveness of ventilation for Radon reduction is limited and only appropriate for situations where only modest reductions are needed.
- Increased ventilation will be most successful in houses that are more airtight and have low natural ventilation rates.
- An HRV might reduce Radon concentrations by 25-50%.