I'm looking for information and advice about installing a radon remediation system. I know the basics such as cutting a hole in the slab, digging dirt out, and piping it outside with a fan yo create negative pressure under the slab. I've been monitoring my radon level and it seems to be right around 4.5. I want to take action and get it corrected. I have some questions however that I can't seem to find answers to.

I do have two Sump pits, but really don't want to use them for my radon remediation. I don't want them to be sealed since I do like to test the pumps and make sure everything is working. I have a finished basement with an internal French drain along the permiter which empties into the Sump pit, the pits are side by side.

My plan is to put the mitigation system on the opposite end of the basement, but a new hole in the floor and dig out some. Underneath the slab is packed gravel which I know isn't optimal for air flow. How much would I need to dig in depth and diameter?

Would I still need to seal up the Sump pits in order to get thr mitigation system to work properly?

 

Take my thoughts with a grain of salt since I've looked into this in the past but never done it (low enough radon to make it optional).

Hole cavity size: fill a 5 gallon bucket with what you pull out and that will be good

Yes, you'll want to seal the sump pump pits. Otherwise you likely won't get the full negative pressure since it will be sucking air from inside the house. I sealed my sump pits using vapor barrier plastic and tyvek tape. Around the pipes I put one of those roof penetration collars that seals pretty well. Easy enough to cut the tape and check it out as needed. I just leave a roll of tape down there to redo it when needed.