Many modern mountain homes in Western North Carolina are built with passive radon piping—a simple 3-inch or 4-inch PVC pipe routed from the gravel subgrade through the roof without a fan. Unfortunately, natural thermal buoyancy is rarely strong enough to overcome high mountain radon levels. We upgrade passive builder pipes into high-efficiency active suction systems by adding exterior or attic inline fans, differential manometers, and performance testing.
Before mounting a fan, we verify that the existing builder-installed pipe extends properly into clean gravel subgrades and features airtight solvent-welded joints. We perform communication testing to ensure adequate airflow before selecting fan capacity.
Building codes prohibit installing radon fans inside conditioned living spaces. We cut into the existing PVC pipe in the unconditioned attic or exterior chase, install flexible vibration-absorbing rubber couplings, and mount an energy-efficient RadonAway inline fan.
Safety codes require an electrical disconnect within sight of the fan motor. We wire an unswitched electrical circuit with a weatherproof toggle switch or dedicated GFCI outlet to power the continuous-duty radon fan reliably.
We drill into the vertical suction pipe in your basement or utility room and mount a calibrated U-tube differential manometer. Following a 24-hour stabilization period, we execute a post-activation continuous radon test to verify that levels have dropped safely below 2.0 pCi/L.
Passive pipes rely purely on natural thermal stack effect. In cold weather or during heavy rain, soil gas pressures easily overpower passive buoyancy, allowing radon to enter living areas.
In accordance with national safety codes (ANSI/AARST), the fan must be mounted in an unconditioned attic, garage, or outside the building—never in a basement or finished bedroom.
A passive-to-active conversion typically takes 2 to 3 hours, followed by a mandatory post-mitigation continuous radon test to confirm system efficacy.