Radon Mitigation

Radon mitigation systems installed with a floating slab or perimeter trough around the basement. When installing the system the trough or gap at the wall should not be filled, as this will prevent water from draining into the trough. The reason for the perimeter trough is to allow water penetrating into the basement walls to seep or drain into the trough. The water will then drain to the sump pit and not leak onto the floor of the basement. An installed sump pump will then pump the water out of the basement. 

When installing a radon mitigation system in a house with a perimeter drain system, the installer must take special precautions to allow the system to continue to operate as a perimeter drainage system.

1.  Depending upon the level of the Radon, the perimeter though could be left open to allow the drainage system to operate as designed.

2.  The trough can be filled at the bottom with a foam backer rod and then a flowable urethane caulk can be installed over the rod to seal the trough.

3.  The backer rod should be held up from the bottom of the trough to allow any water that drains under the foundation to drain to the sump pump.   

4.  With a block foundation, holes can be drilled into the block below the backer rod, which will allow the water to drain into the bottom of the trough. The caulk can be installed even with the floor with this procedure.

5.  The trough should not be filled with cement or foam, as this will not allow the water to drain into the trough. The cement will also shrink and crack, allowing radon gas to enter the basement.

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