I have a tub and shower with no means of placing bottles of wash or shampoos except for around the edge of the tub. I tried to put in a make-shift shelf tower but it does not fit. I wanted to put porcelain shelves in the corners but I need to do it over existing tile. I have done it before without removing the original tile but it was about 9 years ago and I can't remember how I did it. I tried to remove some of the existing tile to place one shelf but managed to pull out Sheetrock that now has to be replaced. I am not going to ruin any more of the tile or wall.