On Oct 31, 12:39 am, "john"
wrote:
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

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.