tiling wet room

[groucho]

about to tile a wet room with 33 x 33 porcelain. using ardex d 30 for walls. Wet room will have UFH. power shower. do the shower walls have to be tanked? what happens if customer says they dont want it done. On the set up is it best to set up from the floor to see where cuts go? On the shower tray you have to split the tiles for the fall. Any help would be great. ta very much Groucho

[Dave]

Tell the customer that's the whole idea of a wet room...to be tanked.....