Hi - I'm building a natural gas fire pit on a wood deck. I'm trying to insulate the wood deck from the heat - even though I really don't think its going to be a huge problem. It's a 12" high pit with a 24 inch fire ring. The fire ring sits 10 inches off of the deck. The pit is made of stones with vents on all four sides at the bottom. What I'm looking for is a good material to shield the fire ring from the bottom of the deck. People have suggested a piece of stainless steel... but would anything else work? Another metal? Perahps durock or cement board? Or maybe fire bricks? What would be the best idea? Thanks!