Hello. The grout in between the procelain floor tiles in the bathroom is breaking up and coming out in chunks. My 2 year old handed me a large piece this morning!! How do I remove and replace the grout without damaing the tiles...and what is the best grout to use. Note: the floor seems to move under the tiles too...no DIY experience so all the advice you can give me would be much appreciated. It would seem like the best thing might be to lay a vinyl instead but the tiles were very expensive. Thank you.