Frostproofing an existing slab on grade
I am a residential designer working out of northern Wisconsin. I have a project I am working on that has an existing house with a full basement built about 10′-0″ from an existing slab-on-grade garage. I would like to attach the garage to the house with a breezway-type addition. Is there a way to frostproof the existing garage either by digging down 4′-0″ vertically & sliding rigid insulation into the trench, or I believe I have seen shallow frostproofing where rigid insulation is laid horizontally just below grade out to a point out 4′-0″ from the edge of the slab. Or a combination of both? If anybody has any solutions, or input I would greatly appreciate it.
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