I have just purchased my first home, or should I say shell of a home and have a lot of really good renovating ideas and quite a bit of know how. But, here, I am stumped. I have a 9 foot wall where I would like to put a fireplace. It is an inside wall (originally 2 1/2 foot deep adjoining closets) so venting would be quite a job. I got a great deal on a 24" vent-free natural gas log unit but am not at all impressed with the available fireboxes. I would like to build my own firebox using 16 x 16 inch, 1/2 inch thick slate tiles. Is this doable? What would I use to build the frame of the firebox (what would I attach the tile to... sheetrock, backer board...etc.) What would I use for the roof of the firebox?