DIY Radon Mitigation Super Basic Empty Sump System

Disclaimer: I'm not a radon technician. This may violate your local code. It's a temporary vent setup as you're supposed to vent something like 10 feet from windows or doors of occupied spaces (meaning insulated + lived in). If you do what I do you may violate law or endanger your health. But hopefully this helps someone because this stuff is no joke. Keep reading for more on that.

The way I filled the hole back in, is... I placed the pipe in level. Connected it to the other horizontal pipes in the setup. Then once everything was almost done, I started putting the majority of the rocks back in the opposite order they came out, mostly larger ones first. Filled some gaps with smaller rocks. Then I left about 4" of space above the rocks and used your typical pro triple expanding gap insulation foam, which is closed cell. My hope is this seals as good as cement and it probably will. I saw another radon tech use it as a sealer for test holes and he only caulked with it.

Also, just FYI, the electrical & exhaust I have setup is temporary.
Long term I'm going above the roof line, but I just needed something
pest proof and waterproof temporarily. The fan cost me $142 + extension
cord + plumbing materials. The whole project was about $350 depending
on the extra plumbing materials I did/didn't use. I think also if I get
it 15' in length or more you'll get a better draft, similar to a wood
stove and it'll probably pull a lot of air on it's own out the top more,
making it more efficient.

Backstory:

I live in the Granite State... it just so happens the majority of my area has high levels of radon in at least half the houses that is over acceptable levels. Granite means Uranium and Uranium means Radon off-gas and a bunch of other nasty off-gassing. I guess the ground needs to breathe too...

So it turns out I finally bought an electronic radon meter (because I kept forgetting the mail in lab ones) and it was reading levels about 20x danger levels in certain areas. It's so bad that I think it's been affecting my health for the past couple years. Something like the equivalent of smoking more than a cigarette an hour in some areas of the house. I have a split basement, but after recognizing the area of my sump seems to be the main collection area of my radon gas emissions from under the slab, I decided to stick a 4" pipe in it and put a radon fan on it to suck the radon outside. Thankfully my basement is very well drained, and hasn't flooded to my knowledge, so the sump has no pump, and I was able to just turn it into a radon hole. There's no guarantee if you do something similar here to what I do, that it'll lower your levels. Even after this I'm dealing with remaining levels and residual particles (that stick to dust), looking into further sealing, and I'm not sure, but I may need to add a second system or more powerful fan in the near future.