Flooring Tile - What's wrong with my tile?

About 2 months ago, I had the floor of my stall shower replaced, and the bottom 5 rows of tile on the enclosure were also replaced.

I noticed yesterday that the grout has fallen out between some of the tiles, and I can rock some of the tiles back and forth. When I rock them, water oozes out from the grout.

What did the contractor do wrong..and what is the recommended repair? Must all the replaced tiles come off? What about the wallboard underneath?

Thanks!!

While it could be several things, it sounds like they used mastic to set the tiles, a nono in showers. As mastic is water based, when it gets wet it softens up and the bond fails. Also what kind of backer did they use on the walls.

Sounds like the guy who did it doesn't know what they are doing.
More than likely all the tile will have to come off, If they used drywall as a backer that will have to be replaced with a suitable backer, then reset the tiles using thinset.

Also, if he tells you he has been using mastic in showers for umpteen years and he hasn't noticed any problems with it, tell him I said thanks for helping keep me in business fixing his mistakes. :)

Thanks for the tip regarding the mastic. The contractor is coming back later this week and I'm going to see what he is using. If it is mastic, I 'm going to suggest using thinset...even if I have to go and get it myself.

FYI, you CAN NOT get thinset premixed in a bucket, no matter what the label says.

It must be a dry mix in a bag that you add water and/or latex additive to.
Anything in the bucket is subject to failure in wet areas like bigmtk sayd.