QUESTIONMy tile covers my kitchen and all areas in the dining room and living room hallway. I heard a horribly loud cracking sound that went on for at least 15 seconds year ago and never was able to figure out what happened. I later noticed that some of my tiles make the crackle pop sound (like there's no glue) and when knocked on are not solid as others are. This type of tile issue has moved into the kitchen and grows with less tiles solid and more sounding hollow. There are no visible cracks on the tiles, in the grout, or at the walls or edges. Not sure what to do? What is meant by exploratory inspections?
ANSWERANSWER - There is a good chance your tile floor has tented. This is a condition when the tile is installed without resilient movement joints at the perimeters of the rooms, and then the tile expands from increase temperatures or from underlying moisture. When the tile expands and is constrained, then that puts stress on the tile. If the tile isn't bonded well to its substrate, then the tile will debond and sometimes some portions of the floor will actually rise up to a small degree. The fact that you heard the crackle sound and then some tiles sounded hollow, but others did not, suggests that the tile tented causing some tiles to debond.
Although you say there are not cracked tile or cracked grout joints, if the tiles are in fact unbonded, they will be more susceptible to damage if things are dropped on those tiles or if something heavy is rolled over them. Hollow sounding tiles does not mean the tiles have debonded, but it could be a symptom of that condition. The only way to determine the problem to know how to repair it is to remove some tiles to determine if they are bonded or not. If you don't have movement joints at the perimeters of the room then you should install them.
You could just observe the tile for awhile and see how it performs. Or if you want to investigate the problem and try to repair it, then you have to do the intrusive inspection and evaluation by a qualified inspector such as CTaSC provides. This is what is meant by an exploratory inspection to determine what the problem is, so you know how to fix it.