Radon can be easily prevented from entering most properties. This is usually quick (1-2 days’ work) and, even for the most drastic (but effective) of interventions, it still only costs about the same as replacing a few windows. The important thing to recognize is that determining if your home has high radon will not devalue your property, as it is so easily solved. Homes that have been ‘mitigated’ for high radon tend to have the lowest achievable levels – and have amongst the healthiest of indoor air. In other parts of the world, a radon mitigation device is seen even as a selling feature. When considering mitigation, always find someone with C-NRPP (Canadian National Radon Proficiency Program) certification. C-NRPP certification is approved by Health Canada.
Active Soil Depressurization
Sub-slab depressurization (also called active soil depressurization) is the most effective and reliable radon reduction technique. It is also the most common method used by C-NRPP certified professionals.
This method involves installing a pipe through the foundation floor slab and attaching a fan that runs continuously to draw the radon gas from below the home and release it into the outdoors where it is quickly diluted. This system also reverses the air pressure difference between the house and soil, reducing the amount of radon that is drawn into the home through the foundation. One, or sometimes multiple, suction points are inserted through the floor slab into the crushed rock or soil underneath to effectively reduce the radon level in the home.
The sub-slab depressurization pipe is vented at the ground level of the home. The fan can be placed in the basement or an area outside of the living space such as in a garage. If the fan is placed inside the living space of the home, it is usually vented sideways through the rim joist at ground level, with the fan close to the exhaust location. When the fan is placed outside of the living space (e.g. garage) then it is typically vented upwards above the roof. When any active depressurization system is installed, it is recommended to make sure that its operation does not cause back-drafting of combustion appliances such as a furnace, water heater, fireplace, or wood stove in the home. Backdrafting can happen when a room with a combustion appliance is depressurized so much that smoke and combustion gases spilling into the home instead of venting outdoors. Backdraft testing may be done by a trained radon-reduction specialist or a heating contractor.
For more information on mitigation, please visit: the Health Canada website.
To find a local C-NRPP professional, please click on the button below:Find a C-NRPP professional in my area
High radon is a solvable problem. We have studied high radon properties, before and after mitigation and found C-NRPP installed systems to be extremely effective at reducing radon to safe levels. You can see the full, free to access research article by clicking on the figure below.
Long term (90+ days) residential radon before mitigation (red bars) and after installation of a C-NRPP certified mitigation system (blue bars)