Re: Crawl space foundation
Howdy one item to consider is the groundwater/ soils type you have. Another is the norm in your area. Alternative is to install 2 to 4" of foam an not vent but super insulate the crawlspace and add a 10 mil vapor barrier. An why not spend slightly more an have a basement instead of a crawlspace.
Why any crawl space? slab on grade is less expensive again one can super insulate below the slab. An if the room is with a southern exposure then use the slab as a heat sink an take advantage of passive solar heating. Colored concrete floor makes the slab even more attractive...
Any an all of my comments are just my opinion and not to be confused with facts.