Cracking Sounds On Tile 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.
Cracking sounds on tile floor. Tiles laid over existing cracks usually crack due to uneven floor movement along the tile. While this doesn t mean your floors are defective there are various reasons it can occur. 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. Sometimes you might walk across your floors and hear a popping or creaking noise.
Creaking sounds may come from the subfloor or from the wood flooring itself. If your floors are nailed down to the subfloor the popping noise could be coming from the nails. In far more instances the crack was caused by anomalies under or around the tile. Cracked tiles on floors and walls is a problem because it can be difficult to track down the source of the crack.
On the other hand if tiles are not bonded well then tiles and grout can crack and make a noise as they crack. If the paint is blistering then that could be a symptom of a water leak. If the tiles are on your patio a common cause for cracking is the freeze thaw cycle. The glue will fill the hollow gaps while at the same time strengthening the bond.
If the floor has too much deflection that grout can crack among other things. To counter this apply an uncoupling membrane to the concrete before the tile is installed. At times some floors appear to amplify creaking sounds and make them sound much worse than they really are. In areas with cold winters porous tiles like terracotta contract at freezing temperatures and then expand during mild spells eventually leading to cracking.
The question to determine is where is the water coming from. In many cases the crack is not the result of an inferior tile. Thermal expansion one of the main causes of cracking and popping noises that seem to occur randomly in a house mainly deep within the walls floors and ceilings is known as thermal expansion. The advantage of flexible grout is that if there is any movement in the floor the grout flexibility dissipates stress that would otherwise put pressure on the tile and cause cracking.
Generally creaking floors are not caused by settling or soil movement however you may want to check your foundation for cracks or other problems.