What's Wrong With This Picture?
ANSWER: Improperly Installed Radon Mitigation System
There are times when we home inspectors stumble across something so wrong it's hard not to get really excited! This was just such a case. What you are looking at above is a perfect example of how not to install an active radon mitigation system.
The Problem Areas?
The fan is installed in conditioned air space (a living area). The system was on a timer. The draw point was an unsealed sump pit. And, the vent piping appears to have been sealed with duct tape.
Problems Explained
This fan was in the basement. Active radon mitigation system fans must always be installed in
non-conditioned air space, usually at the exterior of the home or an unconditioned attic. It was wired to a timer. Fan are supposed to be on a dedicated electrical circuit to run 24/7 (although in this case that would have made things worse! As I'll explain later). The suction point was a piece of plywood laying over the sump pit. While it is acceptable to draw radon gas from a sump pit, it should always be properly sealed (though again, in this case, it would have actually made things worse) Lastly, if for any reason the vent piping throughout the system is loose or not properly fitted, duct tape is not an acceptable fix.
The Real Danger
Incidentally, when this house was tested for radon with this configuration, the radon reading was reported by the lab to be 224 pCi/L. (The highest levels occurred when the fan was on! Because the fan coupling was not sealed to the exhaust pipe, radon was actually being pumped into the home when the fan was running). So that reading, again, was 224 pCi/L! Remember, the EPA action level for radon is 4.0 pCi/L, and the level in most homes can be successfully reduced to below 2.0 pCi/L with a properly installed active radon mitigation system.
The Lesson
These pictures illustrate why even after testing for radon, another extremely important step is proper installation of the mitigation system--and proper system maintenance from that point on. Remember also, that even after testing once, and even after installing a mitigation system, it's important to continue to test periodically to make sure the system is continuing to operate properly.
