I have underfloor heating which i belive is water running through pipes but powerwed but eletric as we have no gas in the village. In the bathroom the pipes are under concrete floor by about 2mm i think or 2 cms not sure. I Planned to get the bathroom tiled. can i pick any tiles or have i gotta pick somthing special. I know i gotta get some special expandble grout. Thanks for you help peeps.