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Types of Radon Mitigation Systems

WILL COUNTY RADON uses standardized techniques to stop radon entry and reduce indoor radon concentrations. IEMA recommends hiring a licensed Mitigation Professional such as Will County Radon to reduce your indoor radon concentrations.



The most effective measures for reducing radon, without costly renovations, are ones that limit soil gas entry into the building.  Radon is pulled from the soil and rock below the floor slab then exhausted above the home.

One common and very reliable method uses Active Sub-slab Depressurization (SSD). This method uses a radon mitigation exhaust system to reduce the pressure below the floor slab so that the air between the building substructure and the soil flows out of rather than into the building. Sub-Slab Depressurization systems are customized for each property, to address specific mitigation requirements. 





A sub-slab depressurization system consists of PVC piping installed through the basement slab floor with a fan connected to the piping. When the system is on, the fan applies a vacuum beneath the slab and the radon in the soil beneath the building is suctioned into the pipe, then exhausted. 




A  U-tube manometer is mounted to the Sub-slab depressurization system vent pipe. The manometer is used to monitor the operation of the system fan. When the liquid levels in the legs of the manometer are uneven, a pressure differential exists, indicating correct operation of the fan and system. Conversely, if the manometer liquid levels are even, the fan or system is not operating properly and needs repair. 



Covers are installed with observation ports for performance monitoring. This process keeps radon gas from seeping out and it also keeps conditioned air from being drawn into sump.




A Sub-Membrane Depressurization (SMD) may be required for crawl spaces that have exposed gravel or dirt and are not concrete covered. With the SMD method, a plastic sheet (Polyethylene or similar) is permanently installed over exposed rock and soil. A fan is then installed to create suction under the plastic sheeting, drawing the radon out from the soil into a PVC pipe, then safely exhausted away from the home, minimizing radon from entering ambient indoor air, similar to the SSD method.

Both Sub-Slab & Sub-Membrane Depressurization systems must run continuously to be effective. These systems use little electricity, are relatively quiet, and require very little maintenance.  It is recommended that a professional inspect the system periodically to ensure proper performance​


Exhaust fans and piping are typically mounted on the exterior "equipment" side, of the building, towards the back, in the most inconspicuous space.  Optional fan housing units are available for aesthetic purposes. 

Exhaust piping is standard 3 inch PVC. Both the pipe and the fan housing may be painted to match the exterior or the home siding or trim.



Floor cracks are sealed with radonproof caulking.  This caulking is only intended to stop radon from entering the home, it is not a waterproofing technique.  If you have problems with water entering basement or have flooding problems, you will need to have this addressed seperately by a waterproofing specialist.


The State of Illinois requires that a state tag be affixed to every system installed in this state.  Only state licensed Mitigators such as Will County Radon can aquire these tags.  Will County Radon supplies this tag at no extra expense to our customers.

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