Insulating garage with 6” floating slab – GreenBuildingAdvisor

Hi all.

Just purchased a home in Maine that has a garage I’d like to convert into a wood shop. The garage is 24×24 and has no footings. It’s just a 6-8” thick pour on grade with no raised stem wall. I’m not familiar with this style slab, but the surface is in really good shape (no cracks, no heaves) The double sill plate and siding are really low to finished grade and there are rotted corners I’ll need to repair. But before I get into that my question is, if I ultimately want to insulate and condition this space, is there any insulation I should be doing at the slab if there is no frost wall? Is it worth the effort and material? Like I said I plan to insulate the rest of the space, and I’d like to keep it dry in there.