When you have a house or other structure built, you assume that the contractor has taken proper steps to ensure that the structure is going to be stable. The last thing that you expect is to find out that there are foundation problems that could have been prevented if the area had been properly prepared.
Before a foundation is laid, the build pad must be prepared. Of course, this is only the case in on-grade constructions where the foundation sits on the ground. The build pad must be compressed so that the soil beneath the foundation remains firm and solid. Failing to compress the build pad can lead to portions of the soil beneath the foundation expanding or contracting based on the weather conditions.
There isn't too much of a problem when the soil beneath the foundation expands and contracts as one large unit. The issue lies when only parts of the soil beneath the foundation move. This is when the foundation can become cracked or unstable.
Another thing that can impact the foundation at the time of the build is what the soil conditions are like then. If the soil is soggy when the work for the foundation is started, there is a chance that the edges of the soil will begin to dry while the middle remains soggy. This poses a problem, and it is why soil conditions must be considered at the start of every build.
If you have an issue with foundation problems, you need to learn about the options that you have for addressing those problems. You shouldn't be held liable for foundation defects and the cost to repair them.
Source: Foundation Repair Network, "Causes of foundation problems," accessed July 06, 2017