Frost Wall Dampproofing, drain necessary?

I’m doing a slab on grade foundation that sits on concrete 4′ frost wall below grade, 8′ out. Do I need a drain or dampproofing for the 4’ frost below grade ?… I’m doing a slab on grade foundation that sits on concrete 4′ frost wall below grade, 8′ out. Do I need a drain or dampproofing for the 4’ frost below grade ?…Read MoreGreenBuildingAdvisor