I have a new pleasant hearth LWS2200 on 6 inch legs. The manual says I need an R value of 2. I've been going through on the threads and Micore seems to be the best option but I can't find any at local building supply stores or Menards. Can I use a foam or roxul insulation under a regular cement board with either cermaic tile (grouted) or granite slab on top of that? I will have laminate floor under the pad.