Uploaded July 2020 | Updated September 2026, 2 weeks ago
We had our shower tiled recently, and put in a slate threshold as a shelf. The slate was sealed twice with 511 Grout Sealer, but that product was worthless. Within weeks, white stains appeared under soap dishes and soap and shampoo bottles. It is not clear what the stains consist of. Perhaps soap, perhaps coloring from the soap, perhaps hard water residue. Nothing removed the stains: we tried isopropyl alcohol, vinegar, and commercial stone cleaners.
We finally ended up re-sealing the slate using an "enhanced" (what a strange term) sealer that makes the stone look wet. While that hid some of the stains, some remain. Pretty frustrating to have this kind of damage happen so quickly and have neither the slate seller nor the tile installer protect us from this problem.
If you have slate in your shower, you need to be very careful to avoid the stains from the start. This might mean sealing "properly" (whatever that means) or it might mean making sure to rinse and dry the slate after each use (which is annoying). In our experience, once the stains occur, there is very little you can do to remediate.
We had our shower tiled recently, and put in a slate threshold as a shelf. The slate was sealed twice with 511 Grout Sealer, but that product was worthless. Within weeks, white stains appeared under soap dishes and soap and shampoo bottles. It is not clear what the stains consist of. Perhaps soap, perhaps coloring from the soap, perhaps hard water residue. Nothing removed the stains: we tried isopropyl alcohol, vinegar, and commercial stone cleaners.
We finally ended up re-sealing the slate using an "enhanced" (what a strange term) sealer that makes the stone look wet. While that hid some of the stains, some remain. Pretty frustrating to have this kind of damage happen so quickly and have neither the slate seller nor the tile installer protect us from this problem.
If you have slate in your shower, you need to be very careful to avoid the stains from the start. This might mean sealing "properly" (whatever that means) or it might mean making sure to rinse and dry the slate after each use (which is annoying). In our experience, once the stains occur, there is very little you can do to remediate.
