I need some guidance on replacing the shower wall tiles and backer board. Recently, my boyfriend accidentally damaged the shower by putting too much weight on the soap dish, which caused it and two tiles to fall off. When we looked behind them, we found that the backer board is completely rotten. It seems like the grout wasn't sealed properly by the previous owner, leading to this issue. I've done tiling before but I've never dealt with waterproofing or replacing backer board. Any tips would be really appreciated!
2 Answers
First, it’s important to check what kind of backer board you’re dealing with. When you say it’s rotted, it might be a sign that it wasn’t properly waterproofed. Make sure to remove all the damaged material before installing new board. If you can, use cement board as your new backer, since it's more water-resistant. Also, make sure to seal all the joints properly with waterproof membrane before tiling again. Good luck!
You should definitely take a picture of the shower wall for better advice. Backer board itself isn't waterproof, but it should resist moisture as long as it’s not damaged. If it’s plaster as you mentioned, replacing it with a cement board is the way to go. Also, don't forget to thoroughly seal the new grout once you tile!
Thanks for the advice! Just added a photo to show the damage better. It’s clear now that needing a replacement is a must.

Yeah, definitely use a waterproof membrane. It's crucial for avoiding future damage. Good call on getting rid of the bad stuff first!