Tip; make sure you put a bed of thinset mortar under the backerboard then fasten it down with screws, nails or staples.
also dont get any backer board over 1/4 " its really difficult to cut. And a bit of an overkill if you ask me.
[This message has been edited by bradbo (edited August 25, 2003).]
Your critical areas are going to be your perimeters. You need a good caulking around the edges.