I have a gas fireplace and I am going with a wood stove, I was wanting to use the existing fireplace but it is only a fake box on the outside, I was wondering if it would be safe to put the imperial board on the bottom, top, and the sides and put the double wall stainless pipe up the flu. I can get good clearance up the flu, but wonder about the firebox if the board would keep enough heat off of the 2x4 stud to be safe