Hi, I have approximately 80 m² open plan area tiled in 800 mm x 800 mm porcelain tiles. The whole installation is creaking and moving and it has become apparent that the Tiler has used a dot and dab method through out to fix the tiles. I have asked him to come and inspect the installation and give me some advice on the failure but he has denied that he has any culpability saying he has always laid tiles that way. I also have a wet underfloor heating system underneath covered by celectra screedboard. I have told him it doesn’t conform to any TTA regulations or indeed British standard 5385. Any comments would be welcome