We recently had 2000 sq feet of tile taken up and new tile put down. The contracter did an amazing job. After two months, my husband noticed he got grout dust on his hands when he ran them down a joint. The contactor came back and took out all the grout and replaced it. (Looking at the one bag of grout mixture from the first time the floor was grouted that was left over showed the grout was two years old.) Now it is ten days after the new grout has been installed, and we have the same situation. (This time the grout mixture was only two months old.) The contractor is coming back today, and he is at a loss as to what to do. Any suggestions?

I lived in AZ where we used a lot of ceramic tile and we were always told to paint the grout with a sealant. This makes it water-proof and would take care of any chalky problem you're talking about. Grout is mixed with water or other liquid from a powder in the first place so it makes sense to me it would dry right back to a powdery texture.