Does Crawl Space Encapsulation Stop Radon?

March 9, 2025 | Brandon Russell | Encapsulation

Radon gas is a silent threat in many homes, often seeping through foundations and crawl spaces. Invisible, odorless, and radioactive, it poses significant health risks, making radon a critical concern for homeowners. One potential solution is crawl space encapsulation, a process frequently recommended for improving air quality and addressing radon in crawl spaces. But can it truly help prevent radon in crawl spaces and reduce exposure to this dangerous gas?

This guide explores the connection between crawl space encapsulation and radon risks in crawl spaces. You’ll discover how radon infiltrates homes, the health risks associated with it, and whether encapsulation is an effective way to reduce or prevent radon in crawl spaces.

How Does Radon Enter Homes?

Radon is a radioactive gas that forms from the natural decay of uranium in soil. While it typically disperses harmlessly in open air, it can accumulate indoors, becoming a serious health concern. Homes with crawl spaces are especially vulnerable, as these areas provide direct pathways for radon to enter the living space.

Common Entry Points for Radon

Exposed Soil in Crawl Spaces: Dirt or gravel floors in crawl spaces act as open gateways, allowing radon to seep directly into the home.
Cracks in Foundation Floors and Walls: Even small cracks in foundations can allow radon to infiltrate, increasing the level of radon in your home.
Open Crawl Space Vents: Poorly sealed or improperly installed vents can unintentionally enable radon gas to flow inside.
Utility Penetration Points: Gaps around pipes, wires, or other utility entries provide additional access points for radon.

By understanding these entry points, homeowners can better identify radon gas reduction methods to protect their living space from harmful radon concentration.

Why Radon is a Risk Worth Addressing

Radon is more than just an inconvenience—it’s a serious health hazard. The U.S. Environmental Protection Agency (EPA) identifies radon as the second leading cause of lung cancer and the primary cause among non-smokers.

Health risks become significant when radon levels reach 4 pCi/L (picocuries per liter) or higher. Since radon is odorless and invisible, testing for radon is the only way to determine its presence and concentration in your home.

To prevent dangerous buildup, it’s essential to install a radon mitigation system if elevated levels are detected. These systems are specifically designed to reduce radon concentration and protect the health of your household. Addressing radon in your home isn’t just about safety—it’s about peace of mind.

What is Crawl Space Encapsulation?

Crawl space encapsulation involves sealing your crawl space with a durable vapor barrier, often made of polyethylene plastic. It also involves sealing all foundation walls, vents, and openings to create an air-tight environment.

Benefits of Crawl Space Encapsulation

While protection against radon is one of the most crucial benefits, encapsulation serves to:

Control Moisture: Reduce humidity levels that contribute to mold growth and wood rot.
Improve Air Quality: Minimize allergens like mold spores entering the home.
Create Usable Storage Space: Make your crawl space cleaner and more accessible for storage.
Increase Energy Efficiency: Reduce energy loss from drafts and excess moisture.

Beyond making your home more livable, crawl space encapsulation extends the lifespan of your property’s structure by reducing moisture damage.

Does Crawl Space Encapsulation Reduce Radon?

The short answer is yes, but there’s more to the story.

Crawl space encapsulation creates an initial defense by sealing off the ground and foundation walls, cutting off pathways for radon gas to enter the crawl space air. When paired with a radon mitigation crawl space system (such as a radon fan), the sealed environment becomes highly effective at reducing radon levels.

However, encapsulation alone may not lower radon to EPA-recommended levels. A radon reduction system, installed by a qualified radon mitigation contractor, is often necessary to fully vent radon outside the home and ensure a safer indoor environment.

Why Could Radon Levels Still Increase After Encapsulation?

Although encapsulation should reduce radon levels, it can occasionally result in unexpected spikes. This can happen if the crawl space was improperly sealed, leaving gaps in the barrier or leaks in the system. Reduced airflow from sealing off vents can also sometimes trap radon gases inside the space.

If radon levels rise after encapsulation, it’s essential to retest and address any deficiencies in the installation. The EPA recommends allowing several days for radon levels to stabilize post-encapsulation and utilizing a mitigation system if needed.

Crawl Space Encapsulation and Radon Reduction Solutions

Protect your home with expert crawl space encapsulation and radon prevention services from DFX Foundation & Waterproofing Experts. With over 20 years of experience, we help homeowners in Tennessee, Mississippi, and Northeast Arkansas improve air quality, energy efficiency, and radon safety.

Encapsulation is key to preventing radon from entering your home, and combining it with a radon mitigation system ensures the best results. Our licensed and insured team offers affordable financing starting at $79/month, making it easy to keep your home safe and dry.

Contact DFX Foundation & Waterproofing Experts today for a free evaluation and personalized recommendations!