I've been asked to tile over Wavin thermoboard and this particluar water ufh system only allows a floating chipboard/plywood floor or s/c screed to go over it before the floorcovering, I'm going to recommend Karndean vinyl tiles on 18mm ply as I don't know of a floating floor that is solid enough to tile on given that the thickness has to be kept to a minimum as I think they didn't think through the height issues that tiles would cause before they laid the heating! Anyone know if there is yet anything suitable that won't cause issues with porcelain tiles?