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The Inside Outside Guys: Radon – A hidden danger

Ken Calverley and Chuck Breidenstein
Special to The Detroit News

A lot has been written in the past 20 years about radon. Alarms have been sounded while many questioned the need for concern. Why is this an issue now when it hasn’t been before?

A part of the answer to that question is the reality that we are building houses “tighter” than ever before. When houses leaked air to the extent we had to wear three layers to maintain warmth, indoor contaminants were not so much an issue since they quickly migrated outside through old windows or lap siding.

In a tighter home, an indoor pollutant is much more likely to accumulate and even flourish. Witness the mold issue.

Other parts of the answer include the fact that radon was only discovered in 1990 and studies show up to 21,000 deaths a year are attributable to lung cancers caused by radon exposure.

Radon is a product of the decay of natural uranium in rock, soils and water. It is a very small, single atom element that is carcinogenic and can easily infiltrate small gaps and cracks in foundation systems. It can also penetrate gypsum, concrete block, most paints and even thin plastic.

 A byproduct of radon as it decays, called radon daughters, can attach itself to dust and other breathable indoor particulates. Radon can also be found in water. If you have a water well, it is generally advised to test the water for radon, especially since higher concentrations may be present. According to Jarad Beauchamp, owner of Beauchamp’s Water Treatment, Granulated Activated Carbon (GAC) filters are generally very good at filtering radon out of water.

Radon is said to be virtually anywhere in the soils. There are tables in our building codes to indicate, by county, where it is most likely to be found in heavier concentrations. In counties where levels are known to be particularly high, remediation systems must be incorporated into the construction of new buildings. There are several such counties in Michigan alone.

Monitoring and testing can be done by certified air quality specialists, through home test kits or even by in-home use of air monitoring devices such as those used by home inspectors. Short-term self-test devices range from $12-15 each while a home monitoring device may run about $200. Many local health departments will provide in-home test kits that can be sent to a lab for analysis.

Testing in the home is generally initiated in the basement for two reasons; radon is nine times heavier than air and it likely infiltrated the home through gaps and cracks in the foundation and basement floor. It may also be brought into the space through water moving into the sump crock from weep tile surrounding the footings.

Radon is measured in levels of concentration in the air based on Pico curies per liter of air, pCi/l. A threshold level of 4pCi/l is considered an “action” level by the federal government. Although there is long-running debate as to the veracity of this level, it is widely accepted.

Testing in the home is generally initiated in the basement for two reasons; radon is nine  times heavier than air and it likely infiltrated the home through gaps and cracks in the foundation and basement floor.

You may get a reading of 4pCi/l near the basement floor or sump, but read only 1pCi/l in various places throughout the main floor of the home. The best initial management step is to caulk all basement floor and wall cracks and put a sealed lid on the sump crock. Sealing the basement floor with advanced proprietary coatings like those offered at Motor City Floors and Coatings can also minimize radon.

Good air circulation throughout the basement and the home, especially at floor level in the basement, is another strategy to lower concentration levels. If this is done through the HVAC system, a good filtering system can help, especially with the radon daughters.

Passive remediation minimally involves a 4” PVC pipe running into the gravel beneath the basement floor and rising vertically through the house to exhaust above the roof. An active system could be created by adding a fan to the passive system.

Maintaining a positive air pressure in the home, particularly in the basement, is another effective radon management tool.

The best defense is knowing. Get your home and your water tested so you can manage the fight against this invisible intruder.

For more home improvement advice, listen to the Inside Outside Guys every Saturday and Sunday on News/Talk 760, WJR-AM from 10 a.m. to noon or contact us at with your questions.