A fabrication plant has a number of discrete assembly frames (5) for construction the individual panel elements, and has an opening station (1) for discrete assembly frames and a first horizontally arranged station (3) for the lower wall faces of the panel elements. Each individual assembly frame (5) is mounted on a trolley for transporting in turn to the opening station (1), that is, for opening the first assembly station (3) for reinforcement iron, the second station for the upper wall face of the panel element, and a closure station (2) for closing the assembly frames (5).