Mitigation is the process of reducing the indoor radon level. In most cases, mitigation is accomplished by directly addressing the cause of radon entry, the pressure difference between the soil and the lower level of the home. Radon Diagnostic Services does not do mitigation.

Usually,. The most effective and economical approach is "Active Soil Depressurization." This refers to the approach of developing a greater vacuum in the radon source than generated in the home by its stack effect. Typical approaches are sub slab depressurization or sub membrane depressurization, where a pipe is placed through the concrete slab or polyethylene crawl space cover, then routed to a small fan, then to a discharge point above the eave line of the home.

Various names given to active soil depressurization include sub slab suction, drain tile suction, sump pit suction, sub membrane suction and foundation suction. All of these names refer to active soil depressurization.

The cost of a radon mitigation system is totally unrelated to the radon level or the size of the home. Factors that affect the cost include the permeability of the soil under the concrete slab, the magnitude of the stack effect of the home, the size of the fan req1uired to power the system, the amount and routing of the radon pipe and the number of suction points required.

The national average cost of a radon mitigation system is $1,200. The typical St. Louis home costs about $750.00 to mitigate. However, several factors can affect the cost and it is necessary for a qualified contractor to examine the home.

Q) What are the advantages or disadvantages to have a radon mitigation system?

A) The primary advantage is that you will have lower in-home radon levels if the system was installed correctly and it is operating properly.

The secondary advantage, at least in many parts of the world, is that you will see of much lower level of humidity (dampness) inside the building, especially in houses with basements or slab-on-grade floors. The type of mitigation system will be a factor in this situation. In other words, if the system is an active "sub-slab-suction" design or has incorporated a vapor barrier over the bare soil, then this may be one of the additional benefits. In many cases, we have heard of folks getting rid of their dehumidifier after seeing how dry the basement was after switching on their mitigation system.

One of the disadvantages is that you will pay a small energy penalty with an active design because of the energy required to run the small fan). Most will only draw about 50 watts). There is also a small amount of reverse flow inside (conditioned) air that you may have paid to heat or cool. Another possible problem, in a poor installation, is that you may be able to hear the fan running. Fortunately, this complaint is seldom heard and if it is, it is usually easily fixed.