Use of Cement Backer Board?

[sheffd]

I can't remember who posed the question of using cement backer board. I was doing some research for a new oven and was seriously looking at some type of cementitous product. (other than weight, a great insulating property) I found that the standard concrete backer board has a fiber substrate that is combustable at around 300 degrees.

Now, on the other hand, if you are still interested, I also found out that Hardi plank or Hardi backer board would be perfect to line the oven. It is totally noncombustible. It even comes in larger sheets (size is 4' X 8')than the regular concrete backer board (3'X5'). The Hardi plank does not conduct very much heat and can be an excellent choice for lining the inside of the oven. This can certainly cut down on the amount of insulation needed in the wall space. Weight is even less than that of the standard cement board.