Just what is backerboard and why do I need it for my tile installation?
So what is this stuff and why do you need it? Backerboard, or cement board, comes in sheets much like drywall and is used in a couple of ways. It is used on flooring installations as a means of creating a stable and easier to work with subfloor. It is also used in shower and tub enclosures (or anywhere with significant wetness issues) as a means of helping to create a moisture barrier. Unlike drywall, which is not water proof, or green board, which is merely water resistant, backerboard is water proof and when used with a proper moisture barrier help to mitigate headaches down the road.
Check out this ARTICLE by Andrew Hunt for more information about backerboard and how it is used.