Mikey P said:
In a previous life, I was a tile inspector and I have seen it a few times. Most of the time it was not due to anything to do with the substrate. Most of the time it was to do with a poor quality tile (no matter what type it was). After firing, most tiles have a small 'growth' stage. This should be sorted out and stopped by the times tilers come to lay the floor though.
However in some instances (normally where there is high humidity on a hot day), moisture is sucked in through the biscuit of the tile or stone, and it will start to increase in size again. This is why there needs to be expansion/control joints in floors. A few years ago, there was a major tile manufacturer that had almost a 60% failure rate - and everytime, it ended up like the photo's you posted above. It turned out to be a very costly mistake, but, like always, it took a long time for the tile manufacturer to admit their error. Their standard excuse was it was the tilers fault, or there was problems with the substrate etc....
But you didn't cause this issue Mike, so relax 8)
Jim
