Hi. I have just had ceramic floor tiles layed in my bathroom. We had the concrete floor re-levelled and under-floor heating installed. Two days after the tiles were layed we noticed that two had become discoloured. It looks like a water-mark under the glaze. Three days later this has spread to almost all of the tiles.
Could this be moisture being sucked through the bottom of the tiles? If so, could they dry out? Otherwise we are faced with removal of all the tiles (+ the UF heating). Our builder is looking puzzled. He has referred to the tile suppliers who have in turn referred to the manufactureres. But we are not getting very far and the proble is getting worse.
Any cocmments or advice would be most welcome.