Hello,

We are wanting to build a new slab home using ICFs. We are in Zone 4 Midwest US, with a frost depth of about 30".  For frost heave protection, my plan is to pour a footing 30" in the ground and then build up our ICF walls from there, around 12 ft high.  Then backfill the inside with rock to get the slab height above grade and pour it.  The information that seems be lacking when building this type of home is how to properly pour a slab after the walls are complete.  My original thought was to use the brick ledge ICF form on the interior, at the slab height, so when we pour the slab it will be tied to the brick ledge.  However, I read instances where builders say to just float the floor over a good compacted base, not tying it to the walls at all.  Can moisture come up between the walls and slab in this case?

I dont like the idea of setting the walls on a monolithic slab.  It seems wrong to put all the weight of a icf wall on the edge of a slab, not centered over the footing.  Is that wrong of me to worry about?

Thank you in advance for the help!