Notes

Pier and Beam Foundation Problems: More Than Meets the Eye
Problems related to pier and beam foundations can be quite challenging to pin-point as foundation problems with there being many things happening with pier and beam foundations that could normally stop seen in a typical slab on grade foundation, such as the actual sagging of the beams involving the piers, or lateral movement with the piers, or uneven loading of the piers (the industry sort of foundation failure).
So not simply may a pier and beam foundation be subject a similar conditions a normal concrete slab on grade foundation could possibly be susceptible to, but a pier and beam foundation might have additional conditions that might have nothing about the soil supporting the piers. Let's briefly talk about some of such non-soil related problems.
One of the main conditions you may have using a pier and beam foundation has regarding either deterioration (rotting) in the beams spanning between piers (if using wood beams) or excessive deflections (sagging in the beams). As wood beams mature, they have an inclination to disintegrate because they're not thoroughly protected in the environment. As the years pass, the beams begin to increasingly sag, so that everything that those beams are supporting may also sag. A wall being supported by these beams begins cracking, giving the illusion that you have a foundation problem. A structural Engineer would usually be able to show you if this describes a problem
Another very common problem for pier and beam foundations is the lateral movement from the piers. In many instances a floor with a pier and beam foundation is several feet out in the ground, we've even seen houses around town with over 4ft away through the ground. As you'll be able to imagine, if the wind pressure pushes from the house these wind forces must be somehow transferred to the ground which means the top of such piers work as flag poles, swaying backwards and forwards while using wind. It may 't be noticeable for the human eye, however the little movement is sufficient to develop some cracks inside the walls, providing you again the illusion that there is a foundation problem. Once again, useful content educated Structural Engineer would manage to determine if this describes a problem.
Uneven pier loading is an additional common problem for pier and beam foundations. This is usually a problem with all the design of the foundation mainly because it concerns knowing best places to squeeze piers. Heavily loaded areas (like load bearing walls) and lightly loaded areas (like in the middle in the lounge) could settle differentially from each other in the event the design was not done efficiently from the beginning; that's, the piers for the heavy loaded may "sink" beyond the piers inside the lightly loaded areas if the piers were not properly engineered. This differential movement causes cracks in the floors (if using brittle finishes) as well as cracks within the wall. This is the groundwork problem, but this is extremely hard to verify it because it could be easily mistaken for soil movement due for the soil moisture changing. Your best bet is to buy a Structural Engineer to assess the challenge.
We have gone through just a couple instances of problems that you may face using a pier and beam foundation, so that as you will see, not all problems have to do with the inspiration. It is a lot more than meets the eye. The moral of the story is, even though the thing is that a crack it doesn't mean you have a foundation problem, of course, if you want a reputable and unbiased opinion then get a Structural Engineer that doesn't help a foundation repair company.
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