First post here so apologies if it's been covered. I'm planning to build a decent insulated workshop from the ground up but I'm stuck at the slab. I want the slab to be insulated and plan to build the timber frame off it but if I do the usual hardcore, sand, insulation, damp-proof membrane and slab, the edge of the slab will be exposed to the elements & therefore cold. See my drawing with problem area in the circle. No doubt I'm overthinking this but has anyone got a simple solution for insulating the edge of the slab?