If the grout is cracking and coming out, then the tile is loose as well. No
amount of grouting will fix the problem permanently. You will need to
re-tile the floor. This will have to be done properly, and on a floor that
doesn't move/vibrate. The rule of thumb is that the plywood base should be
at least 1 1/4" thick, then you add the cement board and thin-set mortar and
tiles. Yours probably is done the way I see too many TV shows doing it, with
glue or thin-set directly onto the plywood subfloor -- a guarantee of
failure in the future.

"Stu Pidassle" wrote in message
...
Hi,
We are preparing to spruce up our laundry room. The room has a tile
floor with several areas where the grout has broken up. My assumption
is that this is due to the vibration from the washing machine and that
the issue will re-occur if I simply repair the situation with standard
grout. Even though the best approach would be to remove the tile and
replace it with something else, we would like to avoid taking on the
mess and effort of this approach. Can anyone recommend a type of
grout that would be suitable for use on floor tiles, that would flex
enough for use in a laundry room?

Thanks,
Stu