Radon gas enters the same way air and other soil gases enter a home: through cracks in the foundation floor or walls, hollow-brick walls, and openings around floor drains, pipes and sump pumps. You can use a kit to determine whether your home has elevated levels of the gas.
Radon kit order form (PDF)
Dealing with a radon problem
Sealing cracks and other openings in the foundation is a basic part of most approaches to radon reduction. However, by itself, sealing has not been shown to lower radon levels significantly or consistently. In most cases, venting systems with pipes and fans — called "sub-slab depressurization" — are used to more effectively reduce radon. Other methods may also be used, depending on your home’s design and specific situation.
Hennepin County community health department can provide a list of certified radon mitigators in your area. Most homes can be fixed for roughly the same cost as other common home repairs – such as having the house painted or a new hot water heater installed. The average cost is about $1,200, but actual cost can range from $500 to $2,500, depending on your home’s construction and the strength of the radon source.
New home safeguards
Simple and inexpensive techniques can reduce radon levels on average by 50 percent. The same techniques often also decrease the potential for basement moisture problems. The cost to incorporate radon-resistant features in new construction typically is in the $350-500 range and can be as small as $100 since they are consistent with standard building practices to control moisture and increase energy efficiency.