Basement subfloor and Radon - ideas?
I have a minor radon problem in the basement (below the "Action Level") but given the medical history of my family, I am not taking any chances.
To remediate radon, there are two options:
1 - concrete wall isolation
2 - active soil decompression
I am going for option 1 since option 2 is a crapshoot due to the unknown porosity of the soil under the slab. Long story.
For option 1, I am first treating the concrete (slab and walls) with a sealing compound (a reactive type, sodium-silicate based) to minimize the porosity of the concrete. On top, I'll paint with a gas-resistant water-based membrane (i.e. Blue Seal).
So far, no problem.
However, now I need to add a sub-floor and frame the walls.
The whole issue is that the sub-floor needs to have a high R value AND, here is the tricky part, the concrete should not be pierced (nor the walls nor the floor). Traditional sub-floor building process is to use 2x4 on the flat side nailed to the concrete. This is a no-no for me.
How about this?
Step 1: A sub-floor of 2x4 on the thin (not flat) side floating on the painted concrete on top a flexible layer of plastic sheet. Between the sleepers, expanded polystyrene. On top, traditional OSB T&G.
Step 2: Traditional framing for the walls, but nailed/screwed to the ceiling rafters and the sub-floor (not the concrete).
Would this be acceptable (Ontario, Canada)? or does the sub floor absolutely, positively needs to be nailed to the concrete?
Any ideas would be *very* welcomed!
Oh, I forgot. If the idea above is OK, how do I deal with the sloping near the floor sink? I mean, I think the concrete floor still needs to slope towards the sink but what about the subfloor? Does it need to slope too? Or do I just level it?
Last edited by globus999; 06-16-2010 at 01:03 PM.