Radon Mitigation - Techniques

There are certain techniques that are used for almost every type of radon mitigation procedure. They include: Sub slab depressurization, SSD with a crawl space, sealing openings, and air exchangers.

Sub slab depressurization (SSD)

Many homes have a “Sub slab depressurization” system, which uses a fan and PVC pipe to draw air from below the basement floor and then release it above the roof.  The radon fan creates a vacuum under the basement floor.  Smoke will blow back in your face if you turn the fan off.  There is literally no underground air entering the home when the fan is running. This is a very popular choice for radon mitigation.

SSD with a crawl space

Does your home have exposed dirt in a crawl space? If so, the dirt will normally be covered with a special plastic that is sealed to the perimeter walls.  Next, a tee is placed in the pipe of the SSD system. The arm of the pipe will go into the crawl space and then through the plastic.  The fan runs and it draws air from under the basement floor.

Sealing openings

This process isn’t as reliable as other methods for radon mitigation. Sometimes it works, other times, it doesn’t. Through sealing, you can get radon reductions ranging from 0 to 50%, not exactly what you would want.  Sump holes and large cracks near the suction point will usually be sealed to maximize the performance of a SSD system.

Air exchangers

Some homes have unusual conditions under the floor or have large crawl spaces that are inaccessible. SSD systems don’t work sometimes. Instead they are fixed using an air exchanger which has two fans, one blowing air into the house and one blowing air out of the house.  Much of the heat in the exhaust air is saved and returned to the house.  The air exchanger dilutes radon by combining it with outside air.  Because it costs twice as much air exchangers are the last choice for radon mitigation.