Radon Mitigation System in a Sealed Crawl Space; Topping, VA

Challenge

This Topping, VA homeowner was looking for a radon system in their crawl space. The homeowner previously had another company install a reinforced liner on the crawl space floor, that stopped at the foundation walls, seams were taped, but the liner also had U-shaped stakes through it. They also had thin foam board insulation on the walls and dehumidifier.

Radon is a product of the breakdown of uranium and radium rock in the soil. This varies from home to home, and levels are determined by the concentration of uranium and radium in the ground. Radon works its way into the home rising from the soil beneath it and finding its way through cracks in the home’s building envelope and into your living space. Inside the home, radon gas is not diluted, while outside, fresh air dilutes the gas. Radon is the second leading cause of lung cancer, second only to smoking. The EPA recommends mitigating homes that test at 4 pCi/L (picocuries per liter) or higher while the World Health Organization recommends remediation at 2.7 pCi/L.

Solution

To install an effective radon system, we need to completely seal the crawl space from the earth and prevent radon gas from leaking into the crawl space and ultimately the home. Approximately 50% of the air in your homes comes from the crawl space or the basement and comes in through natural gaps in your home’s construction.

First, we installed a corrugated pipe under the existing liner then resealed it. The pipe connects to the radon fan which is installed on the exterior of the home. The Radon fan sucks air and gas from under the liner and up through a discharge line that exhausts above the roofline of the home. The fan comes with a moisture guard to protect the fan and motor from moisture and water damage. Radon is exhausted above the roofline of the home so that it does not find its way back in the living space, it must be away from any windows as well. Exhausting radon into fresh air, away from any access to the home allows it to naturally be diluted.

We sealed all the U-shaped stakes through the homeowner’s existing liner and ensured that the entire existing liner was sealed to itself and the foundation walls and piers to prevent gas from escaping into the crawl space. The Radon system also comes with a Manometer that allows the homeowner to visually check the pressure of the system and ensure that it is working properly. 

After a radon mitigation system is installed, post-testing is required to ensure that the radon levels were successfully controlled and reduced below 4 pCi/L. The system in this home was successful in improving the indoor air quality for the homeowner.