Does anyone have any links for the earth temperatures under a slab on grade, including under the footer and out a bit from the building? I've seen a very few that are close, and some isotherms w/out temps, but I'd like specific information geared to cold climates (14K dd) with 4" of XPS under the slab, ICF foundation walls, and with/without spacing between the under-slab insulation and the foundation wall. Kind of picky, I know, but that is what I need. Thanks. john