What is this under my shower tiles?

https://preview.redd.it/wf2r9ctwdrle1.jpg?width=3072&format=pjpg&auto=webp&s=cde049bcd8fa1bc12cdd6d35a7280ff8aaae4f9a Is this mold or something else under my shower tiles?! Context: I recently regrouted my shower floor but the grout around the drain would not cure, regardless how long I left it and even with a space heater. I was trying to remove all the grout around the drain one more time and let it 'air out' for a few days before trying to regrout one last time but one of the tiles came loose. Under it I found this black powdery substance that I believe might be mold. The house is about 7 years old and the shower is located on the second floor of the home. I did post to r/Tile and one comment mentioned 'That is your mud bed under the tile. You have an older style "water in, water out" shower system that isn't working as intended. The drainage weep holes have likely clogged'. What can I do to fix it or is it a total re-do job? submitted by /u/nellscene [link] [comments]

Feb 28, 2025 - 13:38

https://preview.redd.it/wf2r9ctwdrle1.jpg?width=3072&format=pjpg&auto=webp&s=cde049bcd8fa1bc12cdd6d35a7280ff8aaae4f9a

Is this mold or something else under my shower tiles?!

Context: I recently regrouted my shower floor but the grout around the drain would not cure, regardless how long I left it and even with a space heater.

I was trying to remove all the grout around the drain one more time and let it 'air out' for a few days before trying to regrout one last time but one of the tiles came loose. Under it I found this black powdery substance that I believe might be mold. The house is about 7 years old and the shower is located on the second floor of the home.

I did post to r/Tile and one comment mentioned 'That is your mud bed under the tile. You have an older style "water in, water out" shower system that isn't working as intended. The drainage weep holes have likely clogged'.

What can I do to fix it or is it a total re-do job?

submitted by /u/nellscene
[link] [comments]