How do you repair grout that comes loose so it doesn't continue to happen?


We renovated our upstairs master bathroom 2 years ago. We used 12X24 porcelain tiles. We opted for very thin grout lines, the grout is coming out and there is movement in the tiles. The contractor said he put a thick layer of cement underneath but to fix the problem he would have to remove the dining room ceiling and add support beams. Does seem like the best fix or should we remove the grout and re-grout.


ANSWER - Grout joints in a 12x24 inch tile should be at least 1/8" wide otherwise the grout can't fill the joint as it should.  If the grout joint is 1/16" or less then chances are that is part of the problem.  If the floor has too much deflection that could be the problem or at least a contributing factor to the problem.  There are building code standards and tile standards that state that the floor should not have deflection greater than L/360 (L stands for Length of the span).   If the tile installer knew the floor had too much deflection then he shouldn't have installed the tile, which is stated in the standards.  Sometimes the deflection might not be noticeable, but that much deflection shouldn't cause a problem unless the grout joints are too narrow.  If the grout joint is wide enough to fill with an epoxy grout that may or may not help prevent the grout from coming loose.  You have to remove the existing grout first before you install the epoxy grout.

5 thoughts on “How do you repair grout that comes loose so it doesn’t continue to happen?

  1. Sophie says:

    I believe I have that white powdery substance called Efflorescence coming up through my tiles i my basement bathroom where the grout is causing loosening of the tiles and white powder everywhere. Can I clean the grout out and put a concrete sealer down and then re-grout? How do I clean up the efflorescence coming up?

    • Donato Pompo says:

      The grout should not cause the tiles to become loose. The loose tiles can cause the grout to crack and come loose. To determine if the white power is efflorescence, scrape some up and put it in a small dish and pour vinegar over it. If it effervesces and dissolves then it is efflorescence. If not, it could be latex leaching from the adhesive or grout.

      To get efflorescence you have to have moisture to dissolve the minerals and transport them to the surface of the tile. Removing the grout and using a sealer won’t prevent continued moisture and the sealer will act as a bond breaker. If the tiles are loose, you need to remove them and fix the problem. There are specific products sold at stores for removing efflorescence. It is temporary in removing it, but it doesn’t prevent it from continuing.

  2. Donna says:

    We are going to sell our house. We had most of the main floor of the house tiled 11 years ago, about 565 sq. ft. of it. Much of the grout has disintegrated due to poor installation. It was done by a new crew member who wasn’t properly trained, and wasn’t supervised. I am told we need to tear out the entire floor and start over. The estimated cost is $12000. Could we possibly scrape out the old grout and replace it? If not, we will probably have to stay here. Felling desperate and depressed.

    • Donato Pompo says:

      To determine how to fix the problem, you have know what is the problem and what caused it. The disintegrated grout is likely the symptom of the problem. If you replace the grout without fixing the problem it will likely reoccur.

      It is possible that the installers over-wet the grout that caused it to be weak and maybe the grout is the problem. If so you can grind out the grout and re-grout.

      The problem might be that you have a wood subfloor and there is too much deflection in the floor that is causing the grout to crack and degrade. In this case you need to cross brace the floor joists to make them sturdy and then re-grout. When you re-grout you can use an epoxy grout that will be more resistant to movement. The epoxy grout is more expensive and more difficult to install. When you cut the grout out you have to be careful not to chip the tile edges.

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