The structural engineering that goes into building basements in Southern California is beyond anywhere in the country. The concrete retaining walls are a foot thick and filled with steel rebar. Basements are not common out here, but when Culver City reduced the FAR (Floor Area Ratio) from 60% down to 45%, the only way we could make a profitable spec home was to start building basements that include 10' ceilings, full bathroom, utility room and an egress window well.