I had a tile floor in my kitchen installed about 5 years ago by a very professional guy. He was meticulous. About 2 months ago I noticed a crackling sound when I walked on one of the tiles (14" tiles). I looked but saw no crack in the grout around the tiled area. Just so happens about a week ago the crackling sound went away. My question is ....... is it possible some loose cement under the tile happened and over a two month period of stepping on the floor the loose cement became powder and this is why the sound went away ? The last thing I wanna do is rip up the tiled area and fix it and worry about matching grout if there may be no need to. I know no one can answer this question definitively, but I'm just looking for ideas if this is a common type thing.

Hello. I have 4x4 tile in my bathroom. I would like to put 16x16 ceramic tile down. Can put the new tile on top of the old tile? Or should I remove the old tile then install the new? Any sugesstions would be appreciated. thanks...