High Radon Test?
Mitigation begins with a free on-site consultation to determine the best radon reduction system for your home. Mitigation is the procedure used to reduce radon gas levels. We use proven scientific methods and this is what makes us unique. We follow Health Canada guidelines to illustrate that our design is engineered to maximize efficiency and minimize cost.
The radon reduction strategy is discussed and approved by the homeowner prior to proceeding with system installation. Our goal is to reduce radon levels below 100 Bq/m3.
Radon entry points are identified and sealed. The most effective and reliable radon reduction technique is called sub-slab depressurization (also called active soil depressurization). This is the most common technique used by our C-NRPP certified scientists.
Best location for system is determined after discussion with homeowner. A 5" hole (suction point) is cored in basement floor.
Next, a diagnostic Fan Size Optimization analysis is conducted. Proper fan size is critical in successfully lowering radon level, as well as ensuring maximum efficiency to reduce power consumption. This procedure uses field extension testing to determine how easily air can be drawn from a test hole to a monitoring hole under the concrete floor. This information determines the optimum fan size and number of suction points needed for the radon reduction system design. Typically one radon fan and one suction point is all that is required. In unusual cases where non permeable soil is under the basement slab or inaccessible crawlspaces are encountered, extra suction points or larger size fans may be required.
A sub-slab depressurization system requires installing 4″ Schedule 40 PVC pipe through the concrete slab and attaching a fan that runs continuously. The fan draws radon gas from below the slab before it can enter the home. The pipe exhausts radon through the top of the foundation wall where it is quickly diluted outdoors. This system reverses the air pressure difference between the soil and the home which reduces the amount of radon that is drawn into the home through entry points in the foundation and floor.
The soil in a crawlspace or home with a dirt floor basement can be exhausted using a similar technique called active sub-membrane depressurization. Radon matting is installed over perforated PVC piping and made airtight by securing the matting to the foundation walls with screws, battens and caulking. The Schedule 40 PVC piping is attached to a radon fan and vented outdoors.
If home ventilation is required to further reduce radon levels or to provide indoor air quality control, Heat Recovery Ventilation (HRV) systems are designed and installed by our HRAI certified Residential Mechanical Ventilation technicians. We also balance and clean HRV’s as part of our normal mitigation service. HRV systems help reduce radon by exhausting stale air and providing fresh air into the home.
A short-term 4 day home test is started after the system is installed to confirm the radon levels have been reduced. A Post Mitigation Plot and Assessment Report is included and discussed with the client. A complementary long-term test kit is included with every mitigation installation. Health Canada recommends a 91-day long-term radon test is performed during the next home heating months to verify the radon reduction system performance.
We identify combustion appliances with potential down-drafting (woodstove, gas/oil-fired furnace) and ensure that they have a make-up fresh air duct in place (if not, we install ducting). This is critical for reducing the possibility of carbon monoxide entering the home.
Mitigation systems offer additional benefits beyond reducing radon. Radon fans exhaust moisture from the house resulting in reduced mould and mildew.
Sub-Slab Radon Mitigation System Installation
Coring 5" suction point in slab
Flow Meter Station
Determining airflow with micromanometer at 3/8" test hole
A hole is drilled through the exterior wall for radon fan exhaust pipe.
PVC piping with radon fan is installed and properly labelled with U-tube manometer indicating system is operational.
Sub-Slab Depressurization System
Heat recovery ventilation systems are cleaned and balanced by certified residential mechanical ventilation technicians to insure home is receiving optimum fresh air supply.
A 4 day radon test is started after the system is operational to confirm radon level has been successfully reduced below Health Canada’s 200 Bq/m3 Action Level. Our goal is to reduce level below 100 Bq/m3. A post-mitigation plot and assessment report are provided to discuss installation details and radon test results.