For 2013, the SCF reports a mean family net worth at $534,600, which means that if you added up the total net worth of all families surveyed and divided that by the total number of families in the survey, the resulting value would be $534,600.
Typically the most expensive type of foundation, the full basement variety consists of a slab basement floor with stem walls that extend from the basement floor to the main level of the building and footers. Homeowners who choose this type of foundation will incur higher costs due to the need for deeper excavation. Grading and forms are also needed in addition to drainage, waterproofing and concrete reinforcements in the basement walls. People who choose a full basement foundation may pay as much as $30,000.
Build Your Own House explains the pros and cons of a crawl space foundation. A full basement foundation for an average home can cost $13,000-$30,000 or more, depending on the width and height of the walls, and whether utilities, windows or other features are included.