There were little to no building codes when much of the city housing stock was built around the 1900’s. We can never assume that any building’s foundation will be the same as the last. Before we propose a basement excavation we must always dig to see how deep the existing foundation goes down. Many times, we will dig multiple holes and find the one portion of the home’s foundation is different from the rest. Some areas of Chicago have more sand, some more clay and some even rock. All these conditions will affect the final price of build.