Abstract: A concrete skirting system for a prefabricated structure, such as a modular prefabricated home, comprises a plurality of rectangular precast concrete skirt modules. Each module consists of a rectangular panel extended upward from an integral footing. The panel is of thin, reinforced concrete construction with integral ribs on the inner panel surface which faces into the crawl space beneath the structure. The modules are provided with rabbeted side edges which form a rabbet joint when adjacent modules are installed beneath the lower peripheral edge of the structure. A concrete mold is provided to produce the precast modules.