Building Construction Guide:
Frame: Exterior walls of wood, brick veneer, stone veneer, wood ironclad, or stucco on wood (i.e. frame).
Non-combustible: Exterior walls, floor, and supports made of metal, asbestos, gypsum, or other noncombustible materials (i.e. concrete block, steel frame).
Fire resistive: Exterior walls, floors, and roof of masonry or fire-resistive materials with a fire resistance rating of at least 2 hours (i.e. poured concrete).