Last updated: June 2026
A radon mitigation system, called sub-slab or Active Soil Depressurization, uses a sealed pipe and a quiet fan to draw radon from beneath your foundation and vent it safely above the roofline. This keeps radon out of your living space and typically cuts indoor radon by 90% or more. Most systems are installed in about a day.
What is Active Soil Depressurization?
Active Soil Depressurization (ASD) is the standard, proven method for lowering radon in a home. "Sub-slab" means the system works under your concrete floor slab. "Depressurization" means it creates slightly lower pressure under the slab than inside your home, so radon is pulled away before it can enter your rooms.
How the system works, step by step
- Suction point: we core a hole through the slab into the gravel or soil beneath.
- Sealed pipe: a sealed PVC pipe connects that point to a vent route.
- Radon fan: a quiet, continuously running fan creates suction under the slab.
- Exhaust above the roofline: the pipe carries radon up and releases it safely outside, above the roof, where it disperses.
- Sealing: we seal cracks and major entry points so the system works efficiently.
Why does it reduce radon so effectively?
Radon enters through the path of least resistance, usually gaps and pores in the foundation. By keeping the area under the slab at lower pressure, the system reverses that flow. Instead of radon being drawn up into your home, it is drawn into the pipe and vented out. Done correctly, ASD typically achieves a 90% or greater reduction.
How do you confirm it worked?
We re-test after installation. A post-mitigation measurement confirms your radon is below Health Canada's 200 Bq/m³ action level. If it is not, we adjust the system until it is. [TENANT TO CONFIRM guarantee terms]
Does the system run all the time?
Yes. The radon fan runs continuously and uses very little electricity, similar to a low-wattage light bulb. That constant operation is what keeps levels low year-round.
Explore more: Radon Mitigation · System Installation · Cost · Radon in the Okanagan · FAQ
Curious whether your home needs a system? Call (236) 506-3301 for a free assessment.