It depends on where you live. If you live in a place where the ground freezes in the winter, you must build your foundation deep enough below ground or your fou

It depends on where you live. If you live in a place where the ground freezes in the winter, you must build your foundation deep enough below ground or your foundation will go to hell the first winter after you build it. So in large areas of the midwest, for example, pretty much every house has a basement. In places where the ground doesn't freeze, most people skip the expense of excavating a basement.