How to Save Thousands on Radon Mitigation

There’s a Smarter Way to Reduce Radon

Radon mitigation is often treated as an all-or-nothing decision: install a fan-based system, accept the cost, and live with the ongoing energy and maintenance expenses. But in many homes, radon levels can be reduced more efficiently by addressing how radon enters the basement in the first place.

Radon gas typically enters through concrete pores, cracks, joints, and other direct soil pathways. By reducing radon entry at these points, homeowners may be able to lower indoor radon levels, reduce the size or operating demands of mechanical systems, or avoid unnecessary costs altogether.

How Radon Actually Enters the Basement

Radon forms naturally in the soil and moves upward toward areas of lower air pressure—often the basement. When a home sits on or near radon-producing soil, the foundation becomes the primary interface between the soil and indoor air.

The most common radon entry paths include:

• Microscopic pores and capillaries within concrete slabs and walls

• Floor and wall cracks

• Control joints and cold joints

• Pipe penetrations and utility openings

• Sump pits and uncovered drains

These openings provide low-resistance pathways for soil gases to enter the basement. Even when a basement appears dry and intact, radon can still migrate through concrete and accumulate indoors. Limiting these entry points reduces the amount of radon entering the home and often lowers baseline radon levels before any mechanical mitigation is considered.

Seal Concrete to Reduce Radon at the Source

RadonSeal® Deep-Penetrating Concrete Sealer works inside the concrete itself. Instead of forming a surface coating, it reacts within the concrete’s pore structure to reduce air, vapor, and soil-gas movement.

When used as part of a radon-control strategy, sealing concrete can help:

• Reduce diffuse radon migration through slabs and foundation walls

• Lower baseline indoor radon levels

• Improve the efficiency of fan-based mitigation systems

• Eliminate energy loss caused by continuous air exhaust

RadonSeal is water-based, non-toxic, non-flammable, and applied using a standard garden sprayer to bare, unpainted concrete surfaces.

Repair Cracks, Joints, and Direct Soil Pathways

While radon can migrate through concrete itself, the most concentrated radon entry often occurs through direct openings that connect the soil to indoor air.

Effective radon reduction should also include sealing:

• Floor and wall cracks

• Floor-to-wall cove joints

• Control joints and construction joints

• Pipe penetrations and utility gaps

Addressing these defects blocks low-resistance radon pathways and significantly improves the effectiveness of concrete sealing or mechanical mitigation. This step is recommended whether a fan-based system is planned, already installed, or being avoided if possible.

Cost Comparison: Fan-Based Systems vs. Source Control

According to the EPA, professional radon mitigation systems typically cost $800–$2,500, with an average around $1,200, depending on the home and system design.

In addition to installation costs, fan-based systems:

• Run continuously, increasing electricity usage

• Exhaust conditioned indoor air, raising heating and cooling costs

• Require periodic fan replacement and system checks

By contrast, sealing concrete and repairing radon entry points typically costs hundreds of dollars, has no ongoing operating cost, and requires no mechanical maintenance once completed.

Actual costs and results vary by home, climate, and radon level.

For details, see Operating Costs of Fan-Based Radon Mitigation System.

When Sealing Alone May Be Enough — and When It Isn’t

Sealing concrete surfaces and radon entry points can significantly reduce radon levels in many homes, particularly when initial levels are moderate and the foundation is accessible.

However, sealing is not a replacement for fan-based mitigation in every situation.

Homes with very high radon levels, highly permeable soils, or complex foundation designs may still require active mitigation to reliably meet EPA recommendations. In these cases, sealing concrete and repairing entry points can still reduce system size, fan power, noise, and long-term operating costs.

Radon levels should always be verified through testing before and after mitigation.

How Radon Professionals Control Long-Term Costs

Many radon professionals use a layered approach:

1. Seal obvious radon entry points

2. Reduce soil-to-air pathways through concrete

3. Add mechanical mitigation only if needed

Lowering radon entry at the source first often improves reliability, reduces energy loss, and limits maintenance requirements—especially in finished basements and energy-efficient homes.

Reduce Radon Risk Responsibly

There is no known “safe” level of radon exposure, and the EPA recommends action when indoor radon levels exceed 4.0 pCi/L. Reducing radon levels lowers long-term health risk and helps preserve home value.

By sealing concrete and repairing direct soil pathways first, homeowners can often reduce radon levels and significantly lower the cost of mitigation, while improving energy efficiency and indoor comfort.