Installing a Radon Mitigation System
Here are a few photos of the installation of a typical radon mitigation system. The system
is called a "sub-slab depressurization system" as it slightly lowers the air pressure
from under the slab and around the foundation, preventing airflow into the house. While
each installation is a little different in order to adapt to the individual house, the
principals are all the same. Installations in finished basements are not uncommon. Be
sure and discuss this when choosing a certified contractor.
| Part of installing a radon mitigation system requires the sealing of
cracks, crevices, and joints to prevent radon gas from being drawn into the house. Even
a hairline crack is large enough to allow airflow into the house. Here a contractor uses
polyurethane caulking to block the airflow between the foundation wall and the floor slab. |
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The contractor will drill a hole in the floor slab to fit the size of pipe
used in the system. This is typically 3" or 4" diameter PVC pipe. The end of the
pipe fits through the hole and is directed upwards to exhaust radon gas from under the
slab and around the foundation. |
| This is an example of an exhaust fan used to pull radon away from the slab. In
this case, the fan is located in an attic above a garage. The end of the pipe is located on
the outside of the house, in this case above the roof. From the street, it would look like any
ordinary vent pipe commonly found on any roof. |
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This is a U-tube manometer, used to show the fan is in operation. It contains
only colored water. As long as one side of the tube is higher than the other, you know that the
fan is operating correctly and that there is adequate suction to the system. |
Typical costs in the Kansas City area for a system installed in an existing house are
about $800 (as of March 2008). If you use radon-resistant
construction techniques, the cost is about one-third to one-half the cost. You can
discuss this with your builder prior to any construction. Systems installed pre-construction
and post-construction are basically the same but the post-construction system is visible.
Click here for EPA architectural drawings of a passive radon control system for new construction
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