Radon Remedy

Deciding If Remediation is Needed

• The U.S. Congress has set a goal for indoor radon levels to be as low as outdoor levels, which is around 4 picoCuries per liter of air. These units are a measurement of radiation decay rate. What they mean to you is that if repeated testing throughout the years averages out to levels lower than this, then remediation isn't urgent and may not reduce the levels much.

  Don't have the same person who you would use to perform the remediation also perform the testing. A conflict of interest might, for example, lead a tester to cherry pick just the readings that are above 4 picoCuries per liter.

Selecting a Contractor

• The first step of radon remediation is selecting a contractor. You can use the EPA link in the Resources section to find one that is state-certified. As with other home repairs, get at least two estimates and request references. Prices range from $800 to $2,500 in the United States. The difference mainly depends on the remediation method and the house size.

Types of Remediation

• One way remediation methods differ is in whether they reduce radon levels in your home or they prevent the radon from getting into your home in the first place. The EPA recommends the latter approach. Remediation systems can be further grouped by house foundation design. Houses with concrete slabs on the bottom level (as opposed to a crawl space under the house) most commonly use sub-slab suction. This entails putting pipes under the concrete slab (either from inside or outside the house) and creating a sub-slab vacuum. Either fans or passive methods (natural pressure differentials and air currents) create this vacuum. The passive suction method is the less effective of the two. The vacuum causes air in the house to be pulled down into the ground and out through the pipes. These approaches reverse the direction of airflow that drew radon into the house. Note that this will also suck the heated or cooled air out of the house and therefore increase utility bills.

Crawlspaces

• The EPA recommends an approach called "submembrane suction" for crawlspace houses. This entails covering the earth under the house with a high-density plastic sheet and sucking the air out from under it with a vent pipe and fan.

Afterward

• Check the contractor's work afterward. Any exhaust fans should be located either outside or above all occupied floors. A warning indicator to signal if the system stopped functioning should be in place. The contractor should also leave you with written instructions for the system's operation. Have the original tester perform a post-mitigation test 1 month after remediation, to verify that radon levels are now below 4 pCu/L.