I am going to be building a hearth for my Oslo to sit on, and I want to over engineer thinking ahead to the future (in case I get a different stove that needs a higher R value). The installation is on the first floor with wood floor joists and 3/4 decking. I am planning the layers as such: 1. Micore 2. steel 3. Durock 1/2" 4. thinset 5. tile I found these panels that someone linked to @ tractor supply: They are micore with steel over them and an R value of 1.5. I would like to use them instead of 2 seperate layers (micore then sheet metal). My question is, will it matter if the seam for this is under the stove? My hearth is going to be 72"wide X 60", so I will also have a durock seam under the stove. Should I seal the seams with something? If so, what? Also, can I use the cut off from this panel to fashion a blockoff plate (existing masonry chimney), or would the micore not be good that close to the flue? Thanks in advance.