What Is a Vapor Barrier and How Does It Help Prevent Radon Entry?
A vapor barrier is a protective material, usually made of plastic sheeting, that is installed over the soil in crawl spaces or beneath concrete slabs to block moisture and gases, including radon, from entering a home.
How a Vapor Barrier Helps Prevent Radon Entry
- Seals the Ground Surface – Radon naturally rises from the soil. A vapor barrier acts as a shield, preventing radon gas from seeping through exposed dirt floors in crawl spaces.
- Works with a Radon Mitigation System – When combined with a sub-slab depressurization system, a vapor barrier helps direct radon gas toward a venting system rather than into your home.
- Reduces Moisture and Mold – By blocking moisture, a vapor barrier also helps prevent mold growth and improves indoor air quality.
- Enhances Energy Efficiency – Keeping moisture out reduces humidity, which can lower heating and cooling costs.
Where Is a Vapor Barrier Installed?
Crawl Spaces
Placed over dirt floors and sealed along the edges to stop radon infiltration.
Under Concrete Slabs
Under Concrete Slabs – Installed during construction to prevent radon and moisture from rising through the foundation.
Should You Install a Vapor Barrier?
If your home has a crawl space or you’re concerned about radon levels, installing a vapor barrier is a smart and cost-effective way to reduce risks. Pairing it with a radon mitigation system provides the best protection.
