After the construction of a house is complete, many times homeowners see problems with their house, either due to poor design or poor construction practices or both.
Differential Settlement of foundations is one of the most frequent problems after construction is complete. It can cause so many unpleasant effects which ranges from small hairline cracks on the plaster, to door frames getting out of place and beams cracking, to the point of imminent collapse of the structure.

How can this be prevented?
Both design and construction practices play important roles, in order to prevent differential settlement of foundations. First of all, the soil must be analysed properly with a qualified geotechnical consultant, and the foundation system must be designed per his recommendations, by the structural engineer. This includes soil type and ground water table considerations, loads that are transferred from the structure to the ground, and the foundations that can take that load, without causing settlement above tolerable limits. Not only the bearing capacity of the soil is considered, but the calculations must be done so as to limit the settlement, which is the determining criteria. The result obtained for the individual foundation sizes can sometimes be too wide that the individual foundations start to touch each other which is the point where you make it a single mat foundation. Depending on the soil and loads, piles can also be used, in order to transfer the loads adequately to the ground, and on top of piles you construct pilecaps and then footings. During the construction phase, the geometry and details of the plans must be followed. Note that a local official will want to check the foundations, before you can continue with the construction above it, for the safety of general public so plan your schedule accordingly.