Can You Dig a Basement Under an Existing House?

Basements can be dug under existing houses, but safety and cost considerations may not make it a viable option. The best way to determine if a basement can be added to an existing house is to consult a contractor.

Some items to consider when adding a basement to an existing home:

  • The existing space
  • The existing space is an important consideration when deciding to add a basement to an existing home. Digging out a large area will cost more than finishing an existing unfinished space.

  • How much needs to be dug
  • Local ordinances and codes vary, but most basements need to have ceiling heights of at least 7 feet. An existing basement may not have ceilings this high, so some digging may need to be done.

  • Connecting lines
  • If the basement will have a bathroom or kitchenette, it will need to be tied into the existing sewer system. The location of the sewer lines may also affect how and where the basement is dug.

  • Windows
  • The basement will need large enough windows to allow enough light, as well as an egress to offer an emergency exit. Consider where the windows will go and how large they need to be when the basement is added.

  • Stairs
  • When adding another floor, stairs may need to be added to the existing floor plan. If the home does not have stairs, the main floor needs a large enough space to add them.