We had tiles put down in our kitchen and hall way about 4 years ago. Some of the tiles are now breaking, possibly due to movement. The grout looks terrible and is falling out. We think that the tiles were not stuck to the concrete underneath properly. Would anyone have any suggestions as to whether we should remove all of the tiles or just re grout? If we re grout, will the problem of movement within the tiles be fixed? Thank you for any advice.