SOURCE OF RADON GAS Radon gas results from the decay of radioactive materials (Uranium, Radium, etc.) that are found in the soil and bedrock. Not all soils contain radioactive materials. However, developers do not test sites that may contain radioactive materials before constructing houses, as it is difficult to predict indoor radon concentrations from the tests performed on the building site.

HOW RADON GAS ENTERS THE HOUSE The radon gas, if present in the soil, enters the house through the cracks and joints in the concrete floor slab on the ground, or through the joints in framed floors over crawl spaces. The radon gas can also be released from well water into a house if well water contains radon gas in a dissolved form.

HEALTH RISK EPA estimates the number of lung cancer deaths attributable to radon gas ranges from 7000 to 30,000 per year. According to EPA, radon concentration in excess of 4 pCi/L in the home can cause lung cancer. An estimated 6% of the existing homes in the USA have annual average radon concentrations above 4 pCi/L.

THE RADON TEST

To test the presence of radon gas, our Inspector places two charcoal canisters in the appropriate locations of the lowest floor of the house. The house must remain closed to outside air for 12 hours prior to placing charcoal canisters in the house. The attic fan is turned off, all windows and doors are closed (normal entry is allowed), fire dampers are closed, and the air conditioner must be set to recirculate mode. The canisters are left in place for a minimum of 48 hours. This is enough time for the charcoal to absorb the radon gas. After 48 hours, the canisters are sent to the testing laboratory. A result should be expected within 3 days. The result is mailed directly to the home owner. If the lab result shows radon concentration in excess of 4 pCi/L, then remedial measures will be required to lower radon concentration to below 4 pCi/L. A contractor, who has expertise in radon remedial measures, should be hired to install a sub-slab depressurization system and seal all cracks and joints. The cost of radon testing is $75.