OK here goes. I'm new to wood stoves but have been doing a fair bit of reading on line. We are putting in a hearthstone Tribute. I am having the install done, but I am building the hearth my self. I have the R factors all figured, and the design for the raised platform that the pad will be fastened to. My question is about the tile. I have found many web pages that talk about ceramic tile, but haven't seen much of anything about porcelain. I have picked out a nice porcelain tile, that is .394 inch thick. I have met the R factor with the pad without the tile, but I am curious about it anyway.