Tom this is ringing in my head as I have the local lumberyard (smalltown mom and pop...not the big box!) looking for insulation. They found 1.5x24x48 mineral wool with a 1200 deg rating. I realize that the Roxul that SmokerParts has is rated to 2000.back in the day I found some a little closer and a little cheaper but it wasn't worth it. It was a real pain in my tail.