I'm looking to build a single story, 2000-2500 square foot ICF home in San Jose, CA (zone 3). I'm trying to keep costs down and was wondering what slab & foundation construction design would result in least labor and/or material cost, while also providing a reliable and comprehensive thermal break. I'm thinking a monolithic thickened edge slab with gravel, foam, vapor barrier extending continuously from slab, under footer, and up outside of footer would provide the desired thermal properties while also being possible to complete in a single concrete pour. Is this reasonable and/or possible? A product like the MonoSlabEz seems like it would help keep labor costs down since it would just stay in place, but maybe this is not the case. I'm not sure if post-tensioned would be desirable or not in this application and what the considerations there are. What do people think?

A foundation will beat a floating slab every time. Make the dimensions to match full ICFs and then be a little flexible, as they might be a hair less than 4' long. Don't skimp on the structure. Cut corners on finishes.

Posted By ICFconstruction on 03 Apr 2019 12:47 PM
A foundation will beat a floating slab every time.

Care to qualify that?

I have usd the Monoslab EZ form. Take your time getting it level and straight before the pour. no moving things after. I recommend driving at least two steel pins in to each 8' section on a diagonal, with nails through the holes in the pins to prevent lift. Backfill isn't too important, but leveling the pad the Monoslab forms are placed on is critical.