This past Saturday, we had Radon Mitigation done on our house in response to a at home test kit, indicating 3.6 pCi/L (picocuries/liter). Radon is cancer causing radioactive gas due to the natural decay of uranium in soil. It is found everywhere to a certain extent. Radon accounts for 800 of the 21,000 annual cases of lung cancer. The original recommendation was 0.4 pCi/L which 2/3 of homes in the US would fail. The EPA set a limit of 4.0 pCu/L and the World Health Organization set a limit of 2.7 pCi/L.
We had our house tested when we moved in and our levels were between 2.7 and 4.0 pCi/L. We tested again in April and our level was 3.6 pCi/L. This time we opted for mitigation.
The crawl space was sealed with heavy plastic draped across the crawl space and sealed to the concrete. The concrete corners were sealed with silicone as was all the PVC pipes exiting the concrete. The next step was a PVC outlet attached to the sump pump. This was connected to a fan outside the house which connects to another PVC outlet extending above the roof line by 11 inches. This was capped with mesh.
When operational, the fan should pull fouled air out from under the house and expel it rather than letting that gas sit in the basement. It will take 4 days for all of the seams to dry and the fan to do its thing. In two weeks, we are supposed to do another charcoal test to check Radon levels, which are guaranteed to be 3.9 pCi/L or lower. Given our current levels, a reasonable estimate would be around 2.0 pCi/L.
Bill from Ace Radon did a good job. The transferable warranty is good for 25 years. The fan is guaranteed for 5 years. No routine maintenance is required.
UPDATE: Retest showed our Radon levels at 1.0 pCi/L. I am still planning on getting a continuous monitoring system, but I am in less of a hurry.