QUESTIONMy house was built in 1956. I have owned it since 2012. There is ceramic tile on the floor in the second floor bath. It is the original tile with no signs of repair or cracks in the tile or grout. There is an area about 15x15 inches that makes a crackling noise when you step on it. It is not near the tub or the sink and not a place where it get wet (at least not from the top). It only makes the noise when it is stepped on.
Since this has only occurred in the last 4 weeks, something has changed. I have never had ceramic tile before so I have no idea. I can live with the noise but don't want to ignore it if it will become a larger problem. Could it be water leaking underneath the tile? Any suggestions/ideas will be GREATLY appreciated.
ANSWERANSWER - I assume that the crackling noise that you are hearing can also be considered a squeaking sound that some say they hear on tile floors over wood sub-floors.
Because you say that the tile floor in question is on the second floor, I am going to assume that the tile is installed over a wood sub-floor. There may be a cement backer board or a mortar bed between the tile and the wood sub-floor or it could be that the tile is bonded directly to the plywood sub-floor or over a wood underlayment.
Since the crackling or squeaky sound you are hearing when you step on those tiles is over a relatively small area, and that it recently started making the sound, there are a couple of reasons of what is causing that condition.
One reason the tiles could be making noise when you step on them is that the tile might have debonded in that spot, so when you walk on those tiles they move and make that sound. The reason it may have debonded might be because you don't have movement joints at the perimeter of tile installation where it transitions to the walls or in other locations where there should be a movement joint.
Movement joints are grout joints filled with a resilient sealant that is normally a silicone sealant. Tiles can expand as they are subjected to moisture in the form of humidity or water, or if they are subjected to temperature changes or if the tile floor has excessive deflection. So that is why you have movement joints to mitigate the anticipated movements that the tile floor can be subjected to. If the tiles expand and are constrained, then the tiles can be subjected to stress that is greater than what they can resist, which then can cause the tiles to debond.
Another reason why tiles could be making noise when you step on them, is if they are installed over a wood substrate. If the underlying plywood is degrading either from moisture or excessive deflection, then the layers of the plywood can come loose causing the noise. Or if the plywood was installed without 1/8" gaps between sheets, then if the plywood is subjected to moisture it can expand and buckle up that can cause the tile to debond.
The only way to determine what has caused the tiles to make noise when you step on them, is to remove the tiles and evaluate the underlying conditions. Since there is no visual damage, I would just keep an eye on it and see if you notice any moisture or cracking later on, and then if necessary do some exploratory inspections.