In our coach, we had several tiles falling down before this past summers heat hit. The dealer replaced them 2 times and they fell again. On 3rd trip back to dealer for same issue,I requested that Keystone supply ALL NEW tiles and I would install them and hold them harmless for any more tile issues on our coach.
The DW and I removed the loose tiles, cleaned the wall with alcohol cleansing wipes, let it dry thoroughly, the we applied a very thin coating of clear silicon over the back adhesive. We made sure to get the 4 corners and center of the tile (more like an "X" pattern) and small dabs in the center edges of tile, then applied them back in place. They still haven't moved since that day's now we have 3 full boxes left, minus the 6 pieces we replaced.
DW took the old falling tiles apart and separated and cleaned them, we installed them the same way around the bathroom sink. It ties it all together nicely! (PS..this was all her idea, and I stated it wouldn't work, boy was I wrong, and heavent heard the end of that either,lol).
Darwin & Carla
2018.5 3701LK Montana
2019 3500HD Denali Dually Duramax