How Thick Should My Building’s Foundation Be?
You should consult a foundation engineer to help you determine how thick your foundation should be. It ought to comply with your local or regional codes and standards for thickness. Generally, foundations in colder climates will need to be thicker. In the southern half of the U.S., a foundation that is four (4) inches thick should be enough. In the north, you may need more than eight (8) inches of foundation thickness.