QUESTIONContractor installed tile in 3 different rooms. Kitchen and foyer have same tile, 6x18 ceramic tile bought at a discount warehouse, and bathroom with 4x4 tile bought from big box store. The grout is flaking up in all 3 areas, and some of the larger tile are shifting. Contractor says it’s because the discount tile was “warped” and the humidity was too high. He states he scored and regrouted some areas, but the problem persists. Is this a product problem or an installation problem?
ANSWERANSWER - Normally when grout is soft and flakes it is because the grout was mixed with too much water and/or they used too much water during the the cleanup stage when grouting. The excess water causes excess shrinkage and will tend to pull the cement out of the grout that makes it weaker. Sometimes the grout may have dried too fast and it did not completely hydrate to allow it to adequately cure and get strong. In that case you can re-wet the grout to see if that will cause it to harden further.
So it is more likely the flaking grout is an installer error, but occasionally the manufacturer will maybe have a problem where they didn't add enough cement to the grout. Either way it is the installer's responsibility to take care of the problem; assuming he purchased the grout.
Installed tiles should not shift in any way. The tiles should be well bonded to its substrate. Warpage in ceramic tile is normal from the manufacturing process, but there are tolerance standards that limit what is acceptable. If the warpage was excessive, then the installer should have noticed it as he started installing them and should have not installed them. Humidity should not have had anything to do with a ceramic tile warping, unlike it can affect other types of floor coverings. There are ANSI A108 installation standards for workmanship and ANSI A137.1 manufacturing standards for ceramic tile that mush be met.
The only way to fully understand and verify what the problems are, and what caused them, is to perform a forensic inspection and possibly laboratory testing. Although it may not be practical to spend the money for that investigative work.