My radon evacuation system has been in place for about 10 years and it operating efficiently. However, the caulk that was used around the outdoor fan has deteriorated. When I cleaned up the area to ready it for a new application of caulk I discovered that some of the air is exhausting out at the fan output connection.


enter image description here

Is this ok? Should I caulk the spot where the air is leaking out which is just below the gasket that attached the exhaust pipe to the fan unit? I have photos and a video.

  • 1
    If you have leaks I would want to verify there are no obstructions, most of the pipe should be under a small vacuum, after the blower motor there is pressure but it should be a clear shot to outside pushing the air and any radon outside. I would want to seal any leaks to get all the possible nastys outside. – Ed Beal Jun 11 '19 at 15:11
  • 1
    Your title is correct (mitigation system) - detection (as in the first sentence) is not a feature of any radon system I'm aware of, you need to send samples to a lab for that as far as I know. – Ecnerwal Jun 11 '19 at 15:30
  • Thanks Ed. I posted a video of the leak on youtube: youtu.be/tXO0lUmCpCQ Should I caulk under where the leak is? or maybe replace the gasket? – KATHLEEN M MAKA Jun 11 '19 at 15:33

Since it's low-volume and outside I wouldn't worry about it, but Ed's right that there's some indication of blockage. There should be very little back-pressure on that pipe.

However, I've never seen downspout used for radon systems. I'm not sure how you'd reliably seal that (and it may not be legal where mitigation is required by code). My guess is that it was never completely airtight. I'd be replacing it all with welded PVC or ABS and replacing that mangled no-hub coupler.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.