Both our HeatTrak Mats and HeatTrak Pro (Commercial) Mats can be placed on many surfaces such as: Concrete Grass Turf Wood Gravel* Composite* Stamped Concrete* *Barrier required. A thin layer of insulation, or "a barrier", is required under the heat mats to prevent heat penetration. The following are suggestions for insulation: Consider a pressure-treated plywood segment (Helpful Hint: Home Depot and Lowe's offer complimentary cutting services), with a thickness of just 1/4". Insulation options also include 1/4"-thick polyethylene or neoprene foam.