Frost-protected shallow foundation
I’m still not clear how a heated building frost-protected shallow foundation (FPSF) and unheated building FPSF differ in design and theory. I’m about to try to build myself a small home/shop and I don’t know how far I’ll be able to get before the dead of winter here in Vermont. The cold doom and a potentially unfinished home puts me in the unheated classification for a month or however long it takes me to get insulated but back to heated when I’m finished.
I’m looking to use 3.75″ EPS under slab and 2″ XPS for perimeter. How balanced is the FPSF foundation system, can I add extra under slab or will it stop too much heat loss and freeze below?
I’ve found plenty of construction details but not enough information to understand this aspect.
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