Green Renovation: Dealing with Toxic Radon Gas, Part 2

Jim Mallery

Part 1 explained how carcinogenic radon gas can build up in your home to dangerous levels, but it's easy to test for. In this second and final part of the series, we explore what to do about high levels of radon.

If your home tests high for radon, you must take mitigating measures to bring the levels down. Even if your tests are below the Environmental Protection Agency's 0.4 pCi/L recommendation, you might want to take precautionary steps to drop it even lower.

Why Get Professional Help for Mitigating Radon Levels?

While you may be the consummate do-it-yourselfer, the EPA recommends that mitigating radon be left to professionals. The fixes can get complicated, and the danger of the gas is too serious to risk a botched fix.

Even if you suspect radon is entering through your old house's foundation cracks, simply filling the cracks is unlikely to be your solution. You may miss some cracks, the filler can break down over time, and new cracks can appear.

Sub-Slab Pressurization

The surest way to mitigate radon infiltration is to stop it before it can enter your home. If you have a concrete slab floor, or a basement, this is done by running a series of pipes either through the slab into the gravel underneath, or under the slab. The pipes are connected to a vent and a fan pulls air through the pipes and out the vent.

The outlet of the vent must be as high as the roofline and at least 10 feet from windows and doors.

This system draws radon out of the soil before it can enter the house and is the most effective method. It's probably going to cost $1,500 to $2,500, but when compared to the cost of your life, and the lives of your family members, that's precious little to spend.

Eliminating Radon Gas from a Crawl Space

Crawl spaces use a similar system to get rid of radon. A dense plastic sheet is spread over the dirt in the crawl space, and a vent pipe and fan draw air from under the membrane to the outdoors.

Other crawl-space systems will simply draw air from under the house, without covering the dirt with a membrane. These systems are not as effective, and can add to heating costs by continually pulling cold air under your floors.

Block Foundations: A Bit More Complicated

Cinder block foundations, often found in older homes, can be problematic because they are so porous. Proper sealing and vapor barriers are a must, and there also is an efficient pipe-suction system similar to the sub-slab pressurization method that is designed for use with block foundations.

Other Solutions for Mitigating Radon

There are other ways to reduce radon in your house, though none as effective. Natural ventilation, such as opening windows, will bring fresh air into your home, as will air exchange systems in which fans are used to bring air both into and out of your home.

While it is disturbing that your house may have unsafe levels of carcinogenic radon gas, it is comforting to know that it can be safely mitigated. And while the cost is significant, in most cases it is not prohibitive, so don't put off getting it resolved.

About the Author

Jim Mallery, a semi-retired journalist and onetime registered contractor, has extensive experience remodeling, repairing, and rebuilding homes.

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