I detected some Radon exposure in my basement and am trying to seal it
up to stop the Radon gas seeping in.
I have a concrete basement, walls and slab floor. What I am trying to
seal up is the gap between the slab-floor and the concrete walls. The
gap's width is about 1/16th to 1/4 of a inch and varies depending on
where you look in the basement.
This is probablly a dump question but what is the best way to plug
that gap? I tried using SikaFlex SL (Self Leveling) concrete caulk.
But it just seems to pour into a bottomless void. I guess it must be
the crush rock beneath the slab. I thought I would use this because I
think if would give me the best air tight seal.
1) Am I using the wrong Caulk? I.E. Should I be using a non self
leveling one. That way it would not drip into that bottomless pit. Any
2) Foam backing rod. Could not find one thin enough, so ended up using
window foam insulation. This does work, but it takes ages to slip into
that crack and I have like 300 feet perimiter to do.
3) Should I be trying to fill the crack with some concrete first? If
so is that a bad idea because you want some give in your basement to
allow for thermal expansion etc.
4) How would a professional Radon company seal a basment? Can I
replicate what they would do? i.e. am I doing this all wrong?
Thank you for your kind help.
Warmest regards, Mike.