Radon Month: One Fix That Cut Your Readings

In a recent ground-level retrofit, passive sealing wasn't enough. The decisive step we took was installing an active sub-slab depressurization system. We cored through the foundation and installed a continuously running suction fan to reverse the air pressure relationship, venting soil gases above the roofline before they could enter the home.
The data validated the investment: our readings plummeted from a hazardous 14 pCi/L down to a safe 0.8 pCi/L within 48 hours.
My single tip for testing is to avoid short-term 'snapshot' kits. Radon levels fluctuate wildly with barometric pressure and weather; use a continuous digital monitor for at least 7 days to get a weighted average that reflects the true risk.

Many homes have a passive radon stack that only works by natural draft. Adding a quiet inline fan turns that stack into active under-slab suction. The fan creates steady negative pressure under the slab and pulls gas outside. A proper roof vent keeps the gas away from windows and living areas.

A small gauge can show that the system is drawing as designed. Energy use is low, noise is minimal, and readings often drop fast. Install a rated fan and confirm results with a follow-up test today.

An open sump pit can act like a straw that pulls radon into a basement. A sealed, gasketed lid blocks that path while still letting the pump work. Clear covers with bolts and a tight rubber seal on the drain line keep it airtight yet easy to service. A check valve on the discharge line prevents backflow that can leak gas.

Sealing the lid also reduces odors and damp air from the pit. This simple step pairs well with a mitigation fan for better results. Fit a gas-tight sump cover and retest the air this week.

A heat recovery ventilator can lower radon by bringing in fresh air and sending out stale air. Balanced airflow avoids pressure swings that can draw more soil gas. Proper sizing, duct placement, and setup are key to steady results. While not a cure for very high levels, it can trim moderate readings.

It also improves indoor air quality and helps control humidity. Filters and the heat exchanger need regular cleaning to keep performance strong. Have a pro size and balance an HRV and confirm the change with testing.

Exposed soil in a crawlspace is a common entry point for radon. Laying down thick polyethylene and sealing every seam creates a barrier. The membrane should be fastened to walls and wrapped around piers. A vent pipe beneath the liner can connect to a fan if levels stay high.

Encapsulation also cuts moisture, which helps protect floors and ducts. The space becomes cleaner, drier, and easier to maintain over time. Seal the crawlspace and verify the drop with a long-term test soon.

Small gaps in concrete let radon slip in around pipes, joints, and cracks. Using polyurethane sealant and foam backing closes these paths for soil gas. The floor-to-wall joint, sump edges, and pipe sleeves are key spots to seal. Sealing reduces leaks caused by rising warm air and supports any fan system.

This work also blocks bugs and moisture from entering the home. Though not always enough alone, it helps readings move in the right direction. Walk the basement, seal every gap you find, and order a follow-up test.