The required clearance to combustible materials for this gas fireplace/heater is 1/2" at the rear and sides and 0" at the floor. There is a noncombustible zone about a foot high above the metal frame of the glass and a few inches to the sides. The manufacturer's installation instructions say: "If installing Tiles or Faux Rock, first install a ýâ thick (minimum) Cement Board (Hardibacker or Durock Brand) over the face of the fireplace and framing members. Follow by applying Thinset mortar (no polymer additives) using üâ square notched trowel on the cement board surface. Finally, install tile to reach a finish material depth of 1 inch." "If installing Marble or Granite slabs as fascia materials, specify that the inner edges that will be adjacent to the Glass Door are polished ... Attach Marble or Granite slabs to face of unit and to drywall surface using adhesive that does not offgas when hot." I'm going to guess that the problem is some kind of plastic in the backing or setting materials behind the cladding that off-gases or softens from the heat of the fireplace. If this model has heating blowers in it, that might also contribute to the problem. Typical building codes requires that factory-build gas fireplaces be installed according to the manufacturer's instructions and so should your contract. This post was edited by Renovator8 on Sun, Jan 25, 15 at 9:33

To me stacked stone fireplaces look quite modern and seem very versatile in terms of decorating around them. I have had custom-made elegant wood fireplace surrounds with marble tiles, one white painted wood with white marble streaked with gray lines and the other stained wood in a honey color with beige-veined marble and they looked wonderful with Axminster carpets and English-style decor. If that's too traditional for you a stacked stone fireplace seems like the perfect answer. Just picture in your mind's eye what draws you in and go with that. I can't quite picture a stacked stone fireplace for me because the antique Chinese porcelain I collect calls for something a little more formal. Ours is made of bricks which are painted over with a cream color and that's right for me, not too formal and not too informal. We didn't have a choice, it was already there, but it was painted two-tone in beige and brown and that had to be changed immediately.

Linelle, It basically comes down to what material they have and what you want. In my previous house I had black marble tile and loved it. When we built this house, I was going to do the same thing but my fabricators were out of the tile. They simply fabricated from a marble slab exactly as you described above-3 pieces. However, the price difference went from $ to $$$! It is more custom and I guess you could say "historical" looking, but honestly the other way gave almost the same effect to anyone casually glancing at my fireplace.

Others will have better suggestions, but I can't imagine stacked stone looking appropriate with an antique fireplace. What is the style of the fireplace? Victorian? Craftsman? Georgian? If you have an image from the Web that looks similar, I think you'll find great suggestions here.