In many cases the crack is not the result of an inferior tile.
Tile floor cracking sound.
Subfloors need to be quite flat.
Depending on what s happening underneath the flooring these kinds of problems may be caused by among other things structure settlement or weak underlayment.
Sometimes you might walk across your floors and hear a popping or creaking noise.
In far more instances the crack was caused by anomalies under or around the tile.
Laminate flooring materials don t tolerate humpy and bumpy subfloors.
On the other hand if tiles are not bonded well then tiles and grout can crack and make a noise as they crack.
The snapping sounds are almost always traced to an uneven subfloor.
Perhaps the tiles are still partially attached at the corners or somewhere in the middle but it s just a matter of time before a hollow tile begins to crack.
Answer answer 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.
This can occur when a mortar bed method is used and the mortar has delaminated from the supporting layer or when the subfloor itself is not sufficiently thick or well attached.
If the paint is blistering then that could be a symptom of a water leak.
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.
Grout hugs the edges of floor tiles and sometimes seamlessly blends with the tiles exposed surface.
Cracked tiles on floors and walls is a problem because it can be difficult to track down the source of the crack.
If your tile s crack seems to run along the tile s outer edge closely inspect the crack to determine if it s really on the tile or just.
If your wood floor is already down this might mean you have to pull up the section that squeaks to repair the subfloor and then put down a new section of flooring.
If the floor has too much deflection that grout can crack among other things.
The question to determine is where is the water coming from.
Floors that make a popping sound.