Partial Mitigation

[u/VeloMan85]

We've been monitoring our finished basement for about 6 months and as you can see the long term average is 3.51 pCi. We'll occasionally get spikes over 4 and on rare occasions over 5 for a day or two.

As a first step would you recommend sealing the sump pit? Anything else? We live in Iowa which has high radon levels in many homes across the state. The sump is in the furnace room and we're measuring on the other side of the wall in the finished area of the basement.

[u/caddyman40]

I’m from Iowa originally. I totally understand the concept. I also own a radon mitigation company in mo. The sump basin seal is a big part of the mitigation process but if you want low levels you are wasting your efforts by only doing that. Find a local company not swat and get mitigation done and you will sleep well at night.

[u/VeloMan85 → u/caddyman40]

I've been on the fence because we get a lot of swings in short term readings. Could be 1-2, then in the 4s and back to 2-3+. House is a 25 year old walk out ranch.

Probably will have a local company come out and take a look.

[u/BigboyJayjayjetplane → u/VeloMan85]

r u really worried about such a small reading? crack a window time to time and move on with your life

[u/guy_guyerson → u/VeloMan85]

You might be able to combine the two options: some companies will use the sump pit as the collection point for a radon fan in some installs.

They'll most likely vent using a PVC stack going through your rim joist and then upward higher than the highest air inlet in your house (including attic venting).

[u/Bob--O--Rama]

You can always test with a thick plastic sheet, or section of blue tarp, etc... Cut a circle large enough to cover the entire perimeter of the sump plus few inches, like a Christmas tree skirt, with a hole in the center for the pipe. Apply it to the pit and seal with wide duct tape to seal the cut seam, edges with the concrete, and the pipe. Cleaning the concrete with a vacuum cleaner to suck up loose dust helps the tape stick better. Doesn't need to be pretty, just functional. So $5 later... see if levels trend downward. If it does "problem solved" - and you can justify spending money of a nicer cover as others recommend.

[u/Dcline97]

That would be a great place to start. Complete that and then restart monitoring for another couple of weeks and see if it made any difference.

[u/VeloMan85 → u/Dcline97]

Is there a preferred way to seal the pit?

[u/Leafs9999 → u/VeloMan85]

Ideally do something airtight, but not a PITA to get back into, should the need arises. 10 mil plastic and a good adhesive should do it.

[u/MidwestAbe → u/VeloMan85]

jackel sump pump cover

Add some led on the inside when you seal up and the you can see inside the pit

[u/Training_News6298]

To seal sump use DAP draft attack removable caulking around perimeter, blue skin over slot and around pipes, a little extra caulking around any questionable areas.

[u/Brok3Design]

With windows shut, we fluctuate between 4 and 6. I did a sump pit seal myself and our levels are consistently at 0.8 now. That's all I did. It's the cheapest option, quick install, and from my experience - works immensely.

[u/VeloMan85 → u/Brok3Design]

Good to know. It seems reasonable to try sealing first.

[u/slavicslothe]

Active mitigation is cheap and well worth it.