Underfloor Reflective Insulation Because this house is a slab on stumps, it gave us the opportunity to insulate under the concrete slab. It's a great thermal mass but not a very good insulator. So normally under a floor, you would use the polyester rolls between the joists, which are fantastic. But under this floor is [...]The post DIY Projects: Underfloor Reflective Insulation appeared first on ecoMaster.