We are hoping to find an architect familiar with SIP - ICF construction near Little Rock Ar. to work with us on blueprints in the next few weeks.  i  am wanting to have some design ideas nailed down to present .

i  really like the idea of Bill Chaleff's Airfloor and it will fit great with the solar gain we anticipate incorporating. However,  i  have a couple of questions / concerns :

  1. Do  i  need to put down vapor barrier then 2" rigid foam and what about sealing all the joints to create
       an airtight seal ?  (concerned about humidity, mold, radon infiltration)

  2. Will it be beneficial to put down some electric cables in the slab before the pour ?
  
Thanks for the great advice....P K

Yes, a vapor barrier is necessary to control moisture. One modification that I recommend is the installation of 6" of stone with drain tiles under the insulation. This is because of the heavy clay soils in our area, western KY, which create high water tables and poor natural drainage. The drain tiles are routed to daylite or a sump as necessary. Check with your local building officials, they should be able to give a fair appraisal of your soil conditions. They should also be able to discuss the need for radon mitigation. That need varies greatly depending on the soil conditions in your area. In my city, we have no radon to deal with, but 50 miles east and it is a major concern. If you need mitigation, the stone bed above is the starting point for most below slab mitigation schemes.
As to the electric cables in your slab, that is up to your preferences. Possibly in the bathrooms, if you like the tile floors very warm.
If you can't find an architect in your area, contact me. We did a SIPS design project near Little Rock a couple years ago, and would be glad to discuss yours, as well.
Wes Shelby
Design Systems Group
1-877-659-1950
[email protected]

Dear PK ~ The Air Floor system we have used for over 200 installations over 30 years is always evolving. We originally never put down vapor barriers or attempted to seal up the system. My thinking was that it needed to be designed to let water OUT. I believe that the higher temperature would keep moisture from coming up, but I was concerned that mopping or washing the floor would introduce water into the system that I didn't want lying there..... So, what we do these days is install a vapor barrier, but make sure it is pierced or open at the low points; along the bottom edge of the supply manifold so "bulk" water can get out. I don't think it is at all necessary to caulk or otherwise seal all the joints in the foam. Blower door tests confirm there is no measureable air leakage down into the ground. Radon is another matter entirely. My region is NOT a radon one and I have not given any thought - until this - as to how this would be mitigated with the Air Floor design. Perhaps, as the air in the system is part of the house air it would be exhausted just like any other stale and undesireable air through a HRV or ERV system - which you know you should have with any SIP building. Best of luck with your project,

PK ~ Aare we talking about conduit for electrical lines or electric cables as in "electric radiant heat?" The Air Floor never gets as warm as a hydronic or electric radiant slab, it doesn't need to, also that would compromise its ability to store heat as a necessary element of a passive design building. Bill Chaleff 631-726-4477 Water Mill, NY