persimmoncf said:
unfortunatley it sounds like your ceramic tile was not put down over a sufficient sub-floor. To do the job right the tile needs to come up and a subfloor (sheets can be purchased at Lowes) installed over the plywood. Lots of work, so you may want to just clean out the areas you have missing/loose and replace with grout. I have found the premixed latex grout to flex more than the powder mixed with water does. But, This will only temporarily fix it.
I have absolutely, positively, 100% garuntee that the floor was probably not laid on the proper sub floor. I got schooled when we did the kids bathroom. Ripped up the vinyl and there was plywood and what was under the plywood you ask??? Why it was paneling. Yes, I did say paneling, you know the stuff you hang on walls? That's what was there and we ended up gutting the bathroom and starting over.
The kitchen sits up a good inch and a half above the hardwood in the living room. I'd put money on that flooring having something under it it's not suppose to as well. Lemme see if I can dig up a picture.
The Florida room while the tile looks good for the most part if you look closely there are hills and valleys. It's not flat! I have no doubt the sub flooring is something it's not suppose to be.