The Pennsylvania Department of Environmental Protection calls for all homes in the state to be tested for radon. Their testing guidelines state that a radon test should be performed in the lowest livable level of each “structural zone” of the home. A “structural zone” is defined as a foundation that independently contacts the soil. Three main types of structural zones are displayed in the graphic below.
Most homes are built with only one of these three types of foundations and would require only one radon test. However, custom homes or older homes that have had additions will often feature an additional structural zone. One example would be a sunroom addition built on a slab or crawlspace. These homes require a second radon test. In some larger homes you will find multiple basements, slabs and crawlspaces. In these homes multiple radon tests must be taken. Our company has taken as many as four tests in one home.
Tests are to be performed in livable basements, in living areas built on a slab, and in livable areas above a crawlspace. Radon tests are not to be performed in kitchens, garages, laundry rooms or bathrooms.
Special note: There is a mistaken notion that homes with “daylight” basements or homes built on a slab do not need to be tested because they won’t have radon. This is false. Having performed hundreds of radon tests in the state, I can attest to the fact that high levels are found in all foundation types. This is an unfortunate misunderstanding that can result in harm to one’s health. The photo taken below shows five “daylight” basement homes, all of which have radon mitigation systems installed because of high radon. You will notice the tell-tale white exhaust pipe rising above the roof line of each home.