First of all, our inspector walks inside and outside of the house looking for cracks on the floor, walls, ceiling, or even the chimney, if there is one.
The second step is to make sure doors and windows open and close properly; Otherwise, there is definitely a Foundation issue.
In the third step, our inspector starts looking for water leaks that might have caused the foundation issue.
Later in the inspection, our crew uses a water manometer that measures how many inches the soil has moved. Sometimes there is a Foundation settlement issue, and sometimes the homeowner might be facing a foundation heave problem. However, there is a high probability of having a combination of the two problems.