Radon is an odorless, invisible, radioactive gas that can enter your home from the ground through cracks in the foundation, basement slab and crawlspace. A known human carcinogen, radon is the second-leading cause of lung cancer.
New homes like older homes can have high radon levels. Older homes do have more cracks, but radon is a single-atom gas, which can penetrate many materials commonly used in construction. According to the EPA, nearly 1 in 3 homes checked in 7 states had screening levels over 4 pCi/L—the EPA’s recommended action level for radon exposure. The EPA’s website has a map by county of radon levels. If your county is classified as Zone 1 or 2, then I highly advise getting your home checked for radon. Just search for “radon levels by county.” Winter is the best season to measure radon levels. Use an EPA-certified radon detector and have it run a minimum of 24 hours to get an accurate reading. However, I suggest not purchasing a detector because most radon specialists provide this service at little-to-no cost.
So how do homeowners mitigate radon from their home?
Radon is nine times denser than air, and typically gathers in a home’s basement and crawl space. This wasn’t a big issue until basements became living spaces and incorporated mechanical systems. Mechanical systems and their ducts located in the basement or crawl space can distribute radon throughout the house, which is a major concern, especially in bedrooms.
For new homes, the solution is very simple. A PVC pipe is installed vertically from the underside of the basement slab to above the roof line. The pipe helps create negative pressure under the slab, which allows the gas to escape out the top. This is called a passive mitigation system. If the radon is present in the basement, and its levels do not decrease, then an in-line fan—typically located in the attic space—is installed to create an active mitigation system.
When constructing a new home, this cost is minimal. PVC pipe is inexpensive and requires no specialized training to install. Given how serious the health issues can be, and how cheap it can be to mitigate, there’s no reason not to do it. The only issue is planning, which can be done during the design phase. At Hoffmans Architecture, we design our homes to ensure a simple vertical path is available for a radon-mitigation system. On our Home Building Resource page is a Department of Energy radon mitigation sheet outlining critical components to the system. It can be found under Additional Downloads. It’s a great document to provide your builder before starting construction.