Radon Mitigation Methods
The most common method for mitigation is an active sub-slab depressurization system. This system most commonly involves a hole being cored into the basement floor slab. A PVC pipe is then run into that hole going deep enough to reach the sub-slab aggregate. The PVC pipe runs continuous to the exterior of the home, up an exterior wall and above the roof line. On the exterior near ground level there will be an in-line fan, which draws any potential radon gas from the ground under the slab, through the pipe and to the exterior of the home, thus preventing any radon gas from entering the home.
There is also an active sub-membrane depressurization system which is used when crawlspaces are involved. This system is similar to the sub-slab system, but instead a perforated PVC pipe is run horizontally along the surface of the crawlspace. The crawlspace is then completely covered with a radon resistant plastic membrane which will run up and be sealed to the walls, thus forcing any radon gas coming into the crawlspace to go into the PVC pipe and to the exterior of the home.
The two above mentioned technique descriptions are a very basic and simple examples of what can be done. Every home is unique and the method will be different. Other methods used can/will be sealing sump pump pits, sealing large cracks/gaps in the floors and walls and passive systems with no fan.