Abstract: The present invention relates to a sandwich panel comprising a first covering layer, a second covering layer substantially parallel to the first covering layer, a sandwich core provided between the covering layers, and two opposite end surfaces on the longitudinal sides. The invention is characterized in that the end sides are of bevelled or stepped design in such a manner that (i) two sandwich panels which are joined to each other on the end sides in the same orientation and lie one against the other are arranged at 90° to each other, and (ii) two sandwich panels which are joined together on the end sides in an opposite orientation and lie one against the other lie in the same plane, i.e. a 180° connection is realized.

Abstract: A double belt system for producing a prefabricated construction element includes a conveyor system for discontinuously or continuously conveying a first panel, a conveyor system for conveying a first lateral border profile operating as a framework, an application device for applying a foaming plastic material on the first panel and between the first lateral border profile operating as framework and a lateral edge border disposed opposite the first lateral border profile. The double belt system has a top belt and a bottom belt, and at least one protrusion disposed in the belt of the double belt system and facing the first panel and extending circumferentially in the rotation direction of the belt. A recess which is set back in relation to a flat surface is formed in the foamed plastic material with the at least one protrusion.