I would suggest an engineer or architect specialising in residential
If only part of the house is setteling, there are several
The house was added to and the foundations in the two parts are
The ground is different in one of several possible ways.
Some part of the structure was not designed or built to meet present
loads and posts were added to support the failing members.
Ther are so many possible causes and remedies that you need someone on
site to diagnose and suggest a remedy.