The profiled sections (4) have one or more coolant passages, and are mounted between the bent-over edge-strips on a cladding plate (1). The stirrup (10) runs between the edge strips (2), roughly parallel to the plate and at right angles to the profiled sections. It exerts pressure in its lengthwise direction on the strips and/or transverse forces via the strips on the profiled sections. Between the stirrup and the profiled sections there can be a profiled distance-piece (6) parallel to it and engaging positively with the sections. This piece can be of U-section, with a recess in its flanges (7) accommodating the sections with the coolant passages (5).
