Radon problems..

[john]

This is the 2nd time i've tested my house for Radon and its come up above the normal levels both times. The first time around 4.2pci and the most recent 8.0 pci. (these were 48 hour short term tests)

I already had it planned to rip out my carpets on my foundation level. (1st floor - bi-level house) So I was going to try it on my own first with ripping out the carpets and filling in the foundation cracks. (if any are found...which there should be) I would rather go this route first before spending a $1000 or more on a Radon system.

Does anyone recommend what I should use to fill in the foundation cracks? Regular cement caulking in a tube...is that ok ? And should I use some type of sealant coating on top after the cracks are filled?

My sump pump / well water area is closed off and sealed well.. Plus its closed off. (door) so im not worried much about that area.

I do have a sink down there in which i'll have to use a sealant to caulk up the small gap and the bottom of the pipe. Thats another thing... the EPA hotline guys said I should use a polyurethane sealant... while the Kidde radon company I used to test my radon levels recommend using a Silicone sealant for that area.. so im not sure which one to go with there..

Any help would be much appreciated. You guys are the best at giving general advice.

John in PA

[Caesar Romano]

On Wed, 31 Oct 2007 00:39:07 -0400, "john" wrote Re Radon problems..:

Either one will work well.

[hobbes]

Hi John,

I did this in my basement for Radon. I posted my experiences on alt.home.repair as Caulking Hell and Subsequent Redemption. So here is my story again ....

The biggest crack I had was between the basement wall and the concrete slab floor. The floor concrete tends to pull away from the wall as it dries. The gap varies from almost zero to maybe 1/4 inch. You want to fill this crack and make it gas tight.

The process I ended up with is two stage:

1) Use a polyeurethane caulk, which is *NOT* seal leveling first. This will seal up most of the gap but it will not be gas tight.

2) Use a *self leveling* polyeurethane caulk over the other caulk.

Notes:

Both caulks are polyeurethane based. This is because they will stick to concrete and they will stick to each other. You want to use the thicker one first because if you do not, the gap is so large that the self leveling caulk will just drain away into the crushed rock base below your basement slab. Note you do not have to wait untill the thicker caulk dries, I just proceeded with step 2 right away and it worked fine. I really recomend spending the extra 4 dollars on the best caulk gun you can get your hands on. After caulking 150 feet of basement perimeter your hand gets real tired.

For hairline cracks in the concrete slab itself. I used a concrete filler. It somes in a sort of squeezy bottle and comes out like a wet paste. I used a plastic putty knife to smooth it over. Your basement floor will remain dead flat, no bumps.

After I did all this I also ended up installing a radon fan. The caulking is useful in that you keep the warm air in the house and not being sucked out. Some web sites say that sealing alone, although useful, may not lower significantly radon levels. This is because you may miss a bit, basement stairs, near the boiler where you cannot reach etc. Also because the radon gas that remains is more concentrated, you sealed up most of the gas where it could escape. Hence the net lowering of radon levels is not that great if you do not use a fan.

Best, Mike.

[hobbes]

Sorry ... one more thing ... I bought my polyeurethane caulk from Home Depot. Some internet "Radon specialist" sites sell the same stuff at ridiculously high prices.

Best, Mike.

[john]

Mike, I dont understand why you'd use the concrete tube for the very small hairline cracks. Im picturing that the concrete would be so hard to get in there.

Do you know the exact name brands you got? Does the 'seal leveling' brand say its 'seal leveling' on the item?

Another thing..it would probably be difficult to install a radon system in my house because you cant drill down from inside the house. I have Radiant Heating. (heating within the foundation)

[Frank]

Personally I think there has been over kill on the radon issue:

and OSHA have a habit of extrapolating animal test data to zero where in real life there are no effect levels. I would seriously question the 21,000 deaths they attribute to radon caused lung cancer. That said, radon is a gas that comes out of the soil and any non-porous barrier that helps vent it outside will reduce it - even paint on a cement wall. I would do minimum and continue to test until you are satisfied.

Frank

[Clark]

"john" wrote in news:mpudnQxBrbuRAbXanZ2dnUVZ [e-mail]:

[snip]

There are other approaches than going through a hole in the floor. I installed a system that used the drain tile and it worked quite well.

[DonC]

Another approach is to simply install ventilation to exhaust the radon gases. Probably not applicable to clod winter climates.

[hobbes]

Hi John,

Sorry I did not explain it very well. For the hairline cracks I use a concrete paste. It comes in a plastic container. It has the consistency of mayonaise, sort of paste. I am trying to find it on the internet. I got it at Home Depot. It is for concrete crack filling. Ah got it (Sakrete is the manufacturer)

The self leveing Caulk I used from home depot are:

One is self leveling, one is the ticker kind.

As for the Radiant heating .... I do not know ... sorry ... no real idea how to solve that bit ....

Best, Mike.