Floors Creaking, Cracking and Popping

Every new building undergoes diffential settling of floors if constructed on a pier and beam footing system. Within two years all final settling should have occured and cracking should be minimal.

If after that time you have found that a) the movement was extensive, or b) the movement is still occuring, then you should look to whether a geotech report was done for the area before building. Not all soil tyles are the same, and cohesive soils need to be using different piering systems.