I am pondering adding a wood burning fireplace in my living room, which is a cathedral ceiling, with a 2x12 construction floor.
First question: ever seen custom zero clearance fireplaces? It would eliminate the need to bash a huge hole in the floor and pour a footing.
Second question, if I am forced by esthetics to go totally masonry, has anyone experimented with thermal breaks, above or below? I find little discussion about this on the web, and it would seem a major source of heatloss. I imagine the chimney could be steel even on a masonry fireplace, making it easier. The base could be insulated to some extent, but I was thinking with the fairly short height to the floor[~3 feet from the ground to the floor surface] one could pour a footing and support the fireplace structure on heavy steel columns, cutting the thermal exposure to a fraction.