Abstract: Building construction from modules of inverted U shape a full story high with a span of 10 to 30 feet and a depth of 2 to 6 feet. The modules may be monolithic such as of reenforced concrete or plastic foam, or may be of light weight hollow metal construction, assembled together with partitions and end panels. Cast modules can be cast between thin previously formed sheets held by framework to form casting mold, the sheets becoming surfaces of the module.