I would like to floor tile a shower room at the back of the house. The floor used to be a slabbed outside yard, but for the last 20 years it has been enclosed and heated and the slabs have never shown any signs of sucking damp up from the ground even with a rug over them. It would be nice now to make it a little smarter and lay ceramic tiles. I don\\\'t want to fetch the slabs up and lay a DPC. Does anyone have any comments or tips?