Home Addition on Slab or Basement

Summary: If your lot is flat, and all other things are equal, it is generally less expensive (cheaper) to build above grade and to build with wood than it is to build below grade and to build with concrete or masonry.Hello, We are considering adding on to an existing house using a slab foundation. We live in MO and it is very rocky.What I want to know is, would it be cheaper to have a basement