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Community and Q&A

DIY Radon Mitigation Solution

drewintoledo | Posted in Expert Exchange Q&A on

OK so I know none of this is code and could be considered unsafe, but….
I’m installing a fresh air intake system.
In my area is is recommended to install a radon mitigation system.  The area is rated at 4-5.99 pCi/L radon.
Is there any reason I couldn’t just plumb an exhaust line from the fresh air intake unit to the sump crock area and add a fresh air supply line somewhere in the basement?   I know negative pressure is desired to mitigate radon but I feel it might be possible to seal the crock enough to create this effect.
I understand this violates code, and that if the exhaust and intake somehow bleed I could pump radon-laden air into my house…or if the fresh air system fails I could find a build up of radon in the basement.
I know this, but I am just talking theory here.  In theory, is there any reason this couldn’t work?

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  1. Expert Member

    There are a ton of things that could be made to work, but I would at least fine a way to avoid crossing the streams. Otherwise, it's fairly easy to add an exhaust fan to the sump basin, assuming the sump basin has drain lines leading into it. That would meet code, and the sump basin lids are already built for it.

  2. plumb_bob | | #2

    Common radon mitigation plans include basic mechanical ventilation, simply ensuring the air inside the house is exchanged with fresh air from outside.
    The best first step would be to test for radon. The kits are cheap and easy to use and very available.
    If you end up having radon at unhealthy levels then you should put in a dedicated system designed by a professional. If not, no need to worry outside of the normal concerns for air quality.

  3. Expert Member
    BILL WICHERS | | #3

    I'm not sure what you're trying to do here. All you need to do for a basic radon system is to have a small exhaust fan that exhausts to the outside. You could just connect this to a sealed sump, which would be better than nothing. There is no way you're going to create negative pressure in the sump without an extraction fan.

    I would NOT use any kind of fresh air intake fan or anything else on your normal HVAC system if that's what you're considering.


  4. Expert Member
    Akos | | #4

    Why not a passive vent for the sump? You can even leave provisions for a powered vent if needed. An ERV stale air pickup can be installed in the basement near the floor, this way any radon that settles there can also be vented.

    This pretty much accomplishes what you want without any code violations plus it makes better use of the ERV.

  5. drewintoledo | | #5

    I guess the thought here is less exterior penetrations. Since the ERV already has a system which removes stale air from the house and because the exhaust outlet and intake inlet are to be placed at a distance apart as to not cross contaminate stale air with fresh air, adding a sepate radon exhaust seems kind of redundant when an exhaust already exists. The exhaust and intake of the ERV are not able to transpire from one to the other. Outside of code, it seems like a waste to add something that's already there.

    1. Expert Member
      Akos | | #7

      Roof vents are easy to air seal properly, this is the wrong item to try and minimize.

      For a house, any passive system is your friend so if you can manage the radon with a passive vent a the cost of an extra roof hole, I would call that a win overall. As a bonus, it doesn't violate code.

  6. prometheanfire | | #6

    I had similiar radon levels (4-8), what I've done and seems to have worked so far is to seal all the cracks at the edge of the slab in the basement (and any other cracks). I also installed a radon sump lid. That alone has me going up to 3.5 at the high end only and averaging below 2. I still have to seal one crack that's in a hard to reach place as well. That said, I do intend to install a pipe next to my sump exhaust eventually, it's just a lower priority now.

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