Does Backer Board Have to Be Replaced When Re-Tiling a Bathroom?

Backer board does not necessarily have to be replaced when you are re-tiling a bathroom floor. Many times the backer board will be damaged or destroyed when you take up the old tile and thinset. However, if you are able to get the tile up without damaging the backer board, you should be able to reuse it. If you only slightly damage the backer board, you could potentially put some self-leveling compound on the top of the backer board. If the backer board is severely damaged, you should take it up and put a new layer of backer board down.