Our house has a stone tile kitchen floor installed by a previous owner. Since we bought the home 15 years ago, we've had a problem with the grout between the tiles crumbling in certain places. I learned shortly after we bought the house that the grout had been recently repaired in spots. There were issues within the first few years we owned it, which I repaired myself with sanded grout. It crumbled again, so I brought in a professional to do it a few years back. Once again, there are portions of the floor where the grout has crumbled and worn away.
Since these repairs were done by different people with different materials over the years, I'm thinking that the problem is with the floor itself. Perhaps it shifts just enough in certain places to cause the grout to break up.
Is that a reasonable hypothesis? If so, how would I go about making a repair that will last more than a couple of years? Can (or should) I put some kind of metal separators between the tiles to keep them from shifting?
Best Answer
I suppose another way to determine subfloor setup, is if you have a transition to another floor. You could look there. But I suspect the subfloor is not thick enough, allowing the tile to move, causing the grout to crumble. You could try a non-sanded grout, or a siliconized grout.