The extension building of the Brothers Grimm School acts as a link between the two structures of the existing building. Thanks to its positioning on the school premises, the old building with the caretaker's house from the 1930s and the 8-class house from the 1960s with the adjoining social center are connected in terms of urban planning and functionality. The communal uses with the cafeteria and action area are highlighted as a special, single-storey building along Schmiedestrasse. Its roof is extended over the main entrance and additionally emphasizes it.
The generously glazed facade of the one-storey building continues as a band to the schoolyard, where it undercuts the two-storey main building.