We're going to be putting up 2x4 and metal studs in front of the old stone veneer to have the fireplace stick out rather than be flush with the wall. This is a real fireplace that was rebuilt after a tornado took half of it out. Previous owner hooked up a propane tank to gas logs but was originally a wood fireplace. My question is, if we extend it out, is this a problem with a wood burning insert in regards to the gap above and the two sides from heat getting between the new fireplace exterior and previous stone veneer? There will be a granite hearth below it. I'm not very good at explaining so hopefully you get what I'm saying. The total extension out will be approx 6".