Insulating Brick vs FB Board?

[LKJR]

So the supplier I'm talking to has the equivalent of the FB board for $65 a sheet; but also has insulating brick for super cheap. (roughtly $30 for the whole floor)
He says the brick will work better and is a cost savings.

Thoughts?

[RandyJ]

You need at least twice the thickness of IFB to equal the ceramic board. If you have the room to go up then it might be worth it to do the bricks. I have 4" of ceramic board so that would be 8" of bricks to be close to the same value. It all depends on how far you want to go. The insulation is a fairly small portion of the over all build cost, so make sure you do it how you want as you can't go back and redo it later.

Randy