Grout in Kitchen Keeps Coming Out.

Help!
Earlier this year, we had a new tile floor laid in our kitchen. The contractor was recommended by friends. They tore out the vinyl floor and old subfloor, put down new subfloor and laid the tile. It looked wonderful! Well, for about a month.
We then noticed that grout was crumbling in a few areas. The rest was fine, but these stops the grout just fell apart and came out. The company returned and did the grout over in those spots (taking out the old) and it looked great for a couple more months.. when the grout started coming out of the same spots!
The company who did the work has since split up as it was very small so we have no one to call to have them come back again.
Someone told us the problem would be the subfloor is moving slightly under the tiles in those areas (we have an older home) and it is causing the grout to crack and break away. Unfortunately, we can't exactly tear up the floor again.
The areas are small, but unsightly and we have guests coming around the holidays. I am embarassed to show off this new floor and grout missing in spots.
This may sound nuts, but is there anything like "flexible grout" that would have some of the qualitites of caulk? I am thinking if they made grout that was not so bittle and would flex a bit, it wouldn't crack apart in these areas.
Just an idea.
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<snip>

It may very well be movement of the floor, is it "bouncy" at all? If it is, and you have access to the underside, you could consider beefing up the structure underneath by adding blocking or sistering the joists. If the floor is moving much, it's going to keep causing problems and you may even get cracks or popped tiles. Ceramic tile need a very stiff floor to have a long life. What size are your tiles? The problem gets worse with larger tiles.
Do you know if the contractor added latex modifier to the grout instead of just plain water? That makes it stronger and also helps it adhere better to the tile. And did they use sanded grout ?(normal for floors with grout lines wider than 1/8 inch or so.)
You could use color matched silicon caulk instead of grout, but I would not recommend it. It won't match the look of the grout, and is hard to do so it looks at all decent. And if the problem really is floor movement, it's probably only a matter of time until you get cracks or popped tiles, even if the greater flexibility of the caulk gets around your current problem.
HTH,
Paul
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wow, thats a real problem, how long did it take for the grout to come out? ive never used it on my house, because its an appartment, but thats some dodgy work they have done
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The tiles are 12 x 12 and it takes about a month or two for the grout to come out again. We do not detect any movement or shaking in the floor at all, it was just a suggestion from someone on what COULD be the cause.
It's odd, there are three areas in the kitchen where the grout has now come out twice. The rest of the floor is perfectly fine. I just need to find a solution where the grout STAYS.
Dizze102 wrote:

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Get another pro out to look, a real one this time, you probably have movement but cant see it. Nor can we.
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Ryan wrote:

One possibility that hasn't been mentioned yet is that maybe there's excess thinset in these particular groutlines that they failed to clean out.
This would result in minimal grout thickness which would look OK after installation but soon be weak and crumbley.
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Ryan wrote:

Did they put down hardiback boards before installing the tiles? If they didn't that's why the grout keeps popping out. The subfloor mustbe flexing in those areas.
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for tile 1.5" of wood subfloor is usualy safe.
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Ryan wrote:

Home Depot sells matching sanded and no-sanded caulk/grout usually used where tile meets a wall or tub. It's very flexible and should work. As long as the tile stays down, which it should. Many colors are available, comes in a caulk tube or squeeze bottle. Or you can get additives to put into grout which will make it more flexible.
Rich
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