Take clear photos in normal lighting
Send one wide photo of the entire floor, closer photos of the tile surface and grout, and any area where water tends to collect. A short video can help if the layout is hard to understand from photos alone.
Share what you know about the tile
Tell the contractor whether the floor is ceramic, porcelain, stone or another material if you know. Also mention whether it is polished, textured, newly installed or previously sealed or treated.
Describe when it feels slippery
Does the problem appear only with soap? Only after mopping? Around the shower? This helps distinguish drainage, cleaning and surface issues.
Ask about a patch test and appearance risk
A professional discussion should cover the possibility of dulling or colour variation, especially on dark or decorative surfaces. Where practical, a patch test lets you see the expected result before a full-floor treatment.