I have a house that is about 110 years old. There is an addition on the back of the house, and the foundation is concrete, rather than brick. This picture is below an added on bathroom, and you can see the main drain pipe. You can also see concrete foundation. I don't know much about foundation, but it looks like whoever did this dug below the foundation. I'm in somewhat of a panic right now, because I imagine this could be a big problem. Is the back of my house losing its footing?