Wet room tips and ideas

Practically all grout, apart from epoxy grout, is water resistant, but not water impermeable. Which means that water will not damage it, but it will let water through. The mould on the solid wall in the picture on the left is a result of lack of waterproofing and heavy usage.
I highly recommend using epoxy grout on wet room floors. If you are thinking of using it yourself however, you should know that it is not easy to work with. The problematic bits are the reduced working time, sagging and clean up.

Waterproofing a wet room is best done with a liquid waterproofing membrane, with fiber mesh reinforcement for all corners or areas where movement and cracks are likely to occur and the floor.
I prefer this to any other seemingly more solid solution, like ready made membranes and wedi boards because it is just as reliable and at the same time easier to install and cheaper to buy.
All ready made products inevitably have to be joined, and the wedi system uses dowels /5 to 8 p/m2 / wich pierce the board. As much as all joints are waterproofed with products similar to the liquid waterproofing membranes, any superiority which, for example, wedi boards may have are cancelled, as a waterproofing installation is only as good as its weekest point is.

Creating the correct fall can either be done on the spot with exterior grade 18mm ply, or ready made trays can be bought, Aqua-Dec for example. Although theoretically the ready made trays make life easier, in real life I always custom make the floor.
Complications which can arise in the process of fitting such a tray, even if you are lucky enough to find a suitably sized one, are misaligned or out of level joists and less-than-square walls, to mention the most common. You also need to make sure the drain hole in the tray will end up more or less in the middle of the space between two joists.