we are planning to renovate our top floor bathroom. the flooring has a sheet of vinyl thus we were always at peace that the water on thebathroom floor will never leak through. now we plan to put tiles instead, as the vinyl is looking awful after so many years. How do we make sure that the water does not leak through tiles and inbetween the grout? When living in an apartment, our top neighbour was washing her bathroom when it leaked through and started dripping in our apartment's bathroom. We dont want something like this to happen in our house that we moved in.