Radon Mitigation in Quebec
Achieve a lasting reduction in radon concentration in your home with a C-NRPP certified active soil depressurization system.
Health Canada recommends corrective action above this level. Between 200–600 Bq/m³, act within 2 years. Above 600 Bq/m³, act within 1 year.
Radon is the 2nd leading cause of lung cancer after smoking. The higher the level, the faster you should act.
Only a test confirms your actual level
The solution: active soil depressurization (ASD)
We design and install mitigation systems adapted to your foundation, soil, and building. ASD can reduce radon by up to 99% in some conditions, often below 100 Bq/m³.
What is radon mitigation?
Radon mitigation includes all work to reduce the amount of radon entering your home. For existing homes, the primary method is active soil depressurization (ASD), also called sub-slab depressurization.
This technique intercepts radon under the foundation before it reaches living spaces. A specialized fan creates slight negative pressure under the slab and exhausts soil gases outside through sealed piping.
ASD works in two ways: it reverses the pressure difference between the home and soil, and it reduces radon concentration directly under the foundation. It is the main mitigation method recommended by Health Canada for existing buildings.
How does radon enter a home?
Radon comes from natural uranium decay in soil and rock. Air moves from higher to lower pressure zones. When indoor pressure is lower than soil pressure, underground gases can be drawn through foundation openings.
- Cracks in the concrete slab
- Joint between slab and foundation walls
- Penetrations around pipes
- Unsealed sump pits and floor drains
- Concrete block walls and dirt floors (crawl spaces)
How does a radon mitigation system work?
A typical system includes:
- One or more suction points under the slab
- A suction cavity in material beneath the foundation
- Sealed PVC or ABS piping
- A radon mitigation fan
- An exterior discharge positioned to limit gas re-entry
- A manometer or operation indicator
- Sealing of major foundation openings
The fan runs continuously, drawing air and gases from under the slab and routing them outside before radon enters the home.
A system adapted to each foundation type
There is no one-size-fits-all system. The method depends on foundation type, basement, drain, sump, sub-slab communication, and required airflow.
Home with concrete slab
A suction point is created through the slab. A suction cavity under the concrete allows the fan to extend negative pressure. Diagnostic tests may show one or more points are needed.
Home with sump pit or foundation drain
When the sump communicates with the area under the slab, it can sometimes be integrated into the system. The sump must be sealed with an airtight lid while remaining accessible for maintenance.
Crawl space or dirt floor
A durable membrane can be installed on the floor and sealed to walls. The system draws gases from beneath the membrane — called sub-membrane depressurization.
Why do we perform diagnostic tests?
An effective system is not sized by square footage alone. A sub-slab communication test verifies whether suction at one point reaches across the entire slab. These checks determine optimal location, number of points, airflow, and fan size.
What results can you expect?
Active soil depressurization is generally the most effective method for reducing radon in an existing home. A well-designed system can achieve reductions of up to 99% in some conditions, with targets below 100 Bq/m³ often achievable.
Exact results depend on starting level, foundation, soil, cracks, and installation quality. Every home is different — the example below is a real case, not a universal guarantee.
480 Bq/m³ → < 15 Bq/m³
Real Quebec client example.
Where is radon exhausted?
Piping routes gases to an exterior discharge point away from openings and air intakes to reduce re-entrainment risk. Discharge location and pipe sealing are critical design elements.
How do you verify the system is working?
An active system should include a suction indicator — often a liquid-column manometer on the pipe. It does not measure radon directly but confirms pressure difference is maintained.
- Check manometer liquid level periodically
- Do not unplug the fan — it must run continuously
- Contact a professional if the manometer reads zero
- Perform a radon test after installation
- Repeat long-term testing to confirm annual average exposure
Our 7-step installation process
- Review your radon test result — level, test duration, location, and home characteristics
- Foundation inspection — type, basement, cracks, sump, drains, combustion appliances, piping routes
- Diagnostic tests — sub-slab communication to properly size the system
- System design — suction points, piping, fan, discharge, sealing
- Installation — suction point, piping, fan, manometer
- Commissioning — pressure, airflow, sealing, noise verification
- Post-mitigation measurement — confirmation of radon reduction
Why choose a C-NRPP certified professional?
Radon mitigation requires building science, airflow, pressure, ventilation, and safety knowledge. Health Canada recommends a professional certified by the Canadian National Radon Proficiency Program (C-NRPP) when levels exceed 200 Bq/m³.
- Proper diagnostics and method selection
- Correct fan and duct sizing
- Reduced re-entrainment risk
- Operation verification and recognized best practices
Real results from our Quebec clients:
What our clients say
"We went from 312 to 22 Bq/m³. Fast, reassuring service."
"Clean work, site protection, and clear communication throughout."
"355 Bq/m³ in basement → 38 Bq/m³ after commissioning. Truly professional."
One-day installation · Permanent system · Automatic 24/7 operation · Performance guarantee
How much does the fan cost to run?
Typically $1 to $10 per month depending on the model. Full analysis of electricity costs.
Learn more
Radon mitigation system cost in Quebec Radon system installation steps Radon mitigation solutions 50 real Quebec case studies Radon risk map Canada Request a free quoteFrequently asked questions about radon mitigation
Must the fan run continuously?
Yes. The fan must run continuously to maintain negative pressure under the foundation. Extended shutdown can allow radon to build up again.
Is the system noisy?
A well-designed system is relatively quiet. Noise depends on fan size, airflow, duct diameter, and equipment location.
How many suction points are needed?
Some homes need one point; others need several depending on size, interior footings, or poor sub-slab communication.
Will installation damage my home?
Work includes controlled slab coring and piping. Locations are chosen to minimize visual impact.
Can the sump pit be used?
Yes, when the sump communicates sufficiently with the area under the slab. It must be sealed with an airtight lid and remain accessible.
Is an HRV enough?
Ventilation may temporarily lower levels, but ASD intercepts radon before entry and is generally the primary method in existing homes.
Should I keep testing for radon?
Yes. Post-installation testing confirms results. Periodic retesting is prudent, especially after foundation or ventilation work.
At what level should I act?
Health Canada recommends action above 200 Bq/m³. Between 200–600 Bq/m³, act within 2 years; above 600 Bq/m³, within 1 year.
Your result exceeds 200 Bq/m³?
Send us your test result plus photos of your basement, sump, and exterior. A Gaz Radon Québec certified professional will review your situation and propose an adapted system.
Radon mitigation in Quebec City, Montreal, Laval, Longueuil and across Quebec. Order a radon test.
Need more information?
Contact information
Have a question? Email or call us — we respond quickly.
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Address 1360 rue Garnier, Québec, QC G1S 2S9
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Email INFO@GAZRADONQUEBEC.COM
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Phone 418-681-7964