Most problems with the house foundation can be traced back to moisture intrusion. Variations in water and moisture levels swell or shrink soil, which in turn shifts underneath a house’s foundation. When soil moves unevenly, things like uneven floors, foundation movement, sinking foundation, problems with the floor joists, and horizontal cracks in the walls can appear.
Foundation settlement is another problem. In older homes, it's less of an issue because their settling took place long ago. However, in newer homes, it's often seen in the first few years, especially in areas of expansive soil.