In Hans Kollhoff's work in Berlin, the greater urban significance of the work is to be found in the thickness that marks the boundary line between interior and exterior: stone once again here puts forward its ability to be a monument in itself. A silent expressivity runs through the classic architectural elements which are revisited through modern eyes. The goal of austere civic emotion is achieved by the slabs of wall covering in Pietra Forte Fiorentina. On the staircase closer to the user, the slabs are interleaved and become narrower; the same applies to the window surrounds and the corner pillars in the portico. The classic tripartite division is respected: the shaft is embodied by the five upper levels, the capital by the parapet at the top. The shaft, which is made from a single material in a single colour, has its three-dimensional qualities increased by foldable overhanging shading systems.