Receiving radon test results that are higher than the EPA action level of 4 pCi/L can be frightening at first. After all, inhalation of radon gas is the 2nd leading cause of lung cancer in the United States! Luckily, there are a number of effective methods to mitigate high radon concentrations. The mitigation technique that will be most effective depends on a few factors, most important of which is the type of foundation (crawl space, basement, or slab-on-grade). This brief guide will explain the mechanisms of the different mitigation techniques as well as the situations in which they are most effective.

Types of Radon Mitigation Systems:

Active Subslab Suction

Active subslab suction (a.k.a. subslab depressurization) reduces radon concentrations in the home using suction pipes inserted into the rock/soil underneath the home. The suction pipe can be inserted into the floor slab itself, or through the same cap that the sump pump uses, or even into the drain tiles that surround the foundation of some homes. The pipe creates suction via a radon vent fan connected to the pipe. As the name suggests, this type of system requires a slab to perforate, and thus will only be a viable option in homes with basements or slab-on-grade homes. Active subslab suction can require one or many suction pipes depending on how easily air moves beneath the slab (a product of soil/rock porosity) as well as the concentration of radon.

Passive Subslab Suction

This type of subslab suction draws radon up and away from the home without the use of a radon vent fan, hence it is considered a 'passive' mitigation system. I will only very briefly describe this type of radon mitigation because it is difficult, if not impossible, to implement a passive system in a home that is already built. Passive subslab suction