Water can reach behind the finish
Tiles and grout alone are not a complete waterproofing system. Even premium two-component grout does not replace substrate preparation, a membrane and sealed junctions. Design the wet area as a whole, including floor, walls and pipe penetrations.
Continuity matters at every junction
Pay particular attention to corners, floor-to-wall junctions, the drain, threshold and fixings. Use a compatible system with the preparation, tapes, collars and curing times its manufacturer specifies. Mixing unrelated products without checking compatibility introduces avoidable uncertainty.
Test before tiling
After the required curing period, test watertightness in accordance with the selected system. Test conditions and duration depend on the materials and assembly. A fault can then be found and corrected before the finished tiles conceal it. Also check that water drains toward the outlet.
Keep a record
Keep photographs of the substrate and junctions, product details and test records. When glass, furniture or accessories are installed later, coordinate fixings with the waterproofing already in place: a new penetration becomes another wet-area detail.