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Radon Gas – A Concern For Householders

Radon is a radioactive gas produced by the decay of radioactive elements, such as urantum, in the soil. It is tasteless, odorless and colorless. Prolonged exposure to radon may cause damage to lung tissue and result in lung cancer. A recent study by the Environmental Protection Agency (EPA) estimated that 8 million homes contain potentially dangerous levels of radon.

Radon flows from soil into basements through cracks in the foundation, sump pumps or pipes. Low pressure indoor air then sucks the gas up into the house where, without proper ventilation, it can accumulate and cause risk to the inhabitants. If ventilated properly, radon becomes diluted in the outdoor air and no longer presents a health hazard.

Fortunately, elevated levels of radon are very easy to detect and possible to reduce. Testing for radon is very simple. A small collector is placed in the house for a pre-determined period of time and then a lab measures the radon buildup. The simplest form of testing kit is a charcoal canister that absorbs the gas and, within a few days, registers the level of radon. It is important to keep in mind, however, that radon levels may fluctuate on a daily basis depending on varying conditions, such as open windows. Other tests require a period of several months to report an accurate reading. The cost of EPA approved testing kits range from $10 to $50.

The EPA approved tests provide instructions for administering the test. The lab results will report the level of pCi/1 (picoCuries per liter of air), a standard measure of radiation. The EPA’s A Citizen’s Guide to Radon provides information on understanding levels of radon and suggested means of mitigation. Theguide is available free of charge. For information on obtaining a copy of the guide, contact your state EPA office.

There are two general responses to the presence of radon: prevention of radon entry into the structure or removal of radon from the structure. Solutions vary in complexity and expense, and it is advisable for you to consult an EPA certified radon removal/home improvement firm before proceeding with major mitigation procedures.

Strategies for reducing radon levels range from simply improving your home’s ventilation with window or ceiling fans, to piping the radon-laden air out from under the foundation a process which ranges in cost from S800 to $1,500. If radon is detected in your home, you may wish to employ some of the suggested “do-it-yourself solutions, such as installing a window fan or covering any open area near your sump pump, and then retest The cost of having radon removed by professionals will depend on the means of removal, rather than the radon level. Low levels cost just as much as high levels if the same method must be used.

As a homeowner, it is important to be aware of the possible presence of radon. If radon is present, it is important to determine the level of risk and costs involved before proceeding with mitigation strategies. What does this mean for home-buyers and sellers? Concern about radon is no reason not to buy a home since any problem can be corrected easily. The National Association of Realtors has worked closesly with the EPA to inform association members, formulate policy and to educate the public. The association’s board of directors has adopted a radon policy supporting increased efforts by both the private and public sectors to evaluate the extent of indoor air quality problems and to encourage the development of meaningful and affordable monitoring and mitigation strategies. The only way to know if you have a radon problem is to test your home.


Seal Floor & Wall Radon Entry Routes

Caulk and seal openings in the concrete or wood floor and foundation walls where radon can enter the structure.

Seal Crawl Space

Install a gas impervious membrane over the entire soil floor and seal it to the foundation walls with a special adhesive.

Seal Sump

Install a large plastic lid with a built in Plexiglas inspection window over the sump hole and seal airtight so radon does not escape into the structure.

Submembrane Depressurization System

Apply suction under the crawl space membrane using a radon fan, venting the exhaust to the outdoors, at least 10 feet above ground and 10 feet from doors and windows.

Subslab Depressurization System

A/K/A: Subslab suction

             Subslab ventilation

             Active soil depressurization

Applying a negative pressure under the sub-floor, concrete or wood, using an in line centrifugal radon fan which draws radon an air through a PVC plastic pipe and vents it to the outdoors, exhausting at least 10 feet above ground and 10 feet from doors and windows. This fan runs constantly at 40 to 90 watts and costs approximately $30.00/year in electricity.

System Failure Indicator

A “U” tube micromanometer (a plastic U shaped clear tube with a red non-toxic liquid inside) mounted on the PVC pipe which indicate air flow in the pipe so that you can see if the system is working.

Diagnostic Smoke Test

A test performed to indicate soil permeability to determine how much suction is needed by the system. It involves drilling two or more small holes in the concrete floor, attaching a vacuum to one hole and shooting a chemical smoke in the other(s). If the smoke is pulled down the hole by the vacuum, the permeability is good, therefore a high suction system is not needed, only a low suction system is necessary.