I'm getting ready to install my insert in the next week or so and i am going to be installing new tile work. Im just checking on what you guys think as far as the hearth area goes. I poured a 4 inch thick slab as a base and was going to lay down hardybacker on thinset then I would thinset the tile on top. I wanted to run the tile a little bit under the insert an inch or two to make everything look sound and tite. I had found a few globs of dryed up premixed thinset from the last tile job and decied to try to burn it with a lighter. Well it lit up without any problem so now I am concered about what to do next. So what have you guys used in the past to set the tile? Should I be worried? Does it get hot under the insert? Any help in answering any of the questions will be great!!