Backdropped by the bucolic landscape of northern Sigmaringen, the new Bertha Benz Schule by LRO is a striking geometric building whose green roofs help it merge with its verdant surrounds. Consolidating five previously separate schools into one, the campus offers a range of vocational programs across 24,000 square metres. LRO’s approach to material, energy and spatial organisation is holistic, ensuring the building’s longterm sustainability and adaptability. To date, it is one of only six schools in Germany to achieve DGNB Platinum.
Design
The design is organised as two volumes: a circular ring that contains general classrooms and communal spaces, and a rectangular bar that runs parallel to the site’s contours which houses workshops and specialist departments. The inside of the ring is a sheltered courtyard that acts as a meeting space, outdoor classroom and event space. A canteen and music room can be opened entirely to the courtyard, allowing it to act as an auditorium. Windows are protected by canopies and extrusions from the facade. Both volumes are clad in timber and completed with green roofs and solar arrays.
Layout
The reinforced concrete skeleton allows drywall partitions to be removed or relocated without majro structural intervention. Rooms can be extended and combined as required for examination or changing pedagogical needs and the building itself is designed to allow for future extension of both the ring and bar buildings should need require it.
Materials
The design uses two primary materials: concrete and timber. All 21,000m3 of concrete was produced using recycled aggregate by Georg Reisch at the company’s plant in Bad Saulgau. To reduce the volume of concrete used in the floor slabs, a Cobiax system was employed — plastic void formers embedded in the structure that displace material without compromising structural performance. The project uses 54,700 void formers, which saved approximately 710 cubic metres of concrete.
The facade is clad in pre-weathered white fir, a durable and renewable timber that was processed locally by Reisch. Inside, both concrete and wood have been left exposed. The concrete acts as thermal mass, absorbing heat during the day and releasing it at night to moderate temperature and ensure a comfortable climate without reliance on mechanical cooling.
Exterior
All areas of the school have been considered. The buildings are completed with nearly 10,000 square metres of green rooftops by Optigrün along with a substantial solar PV system. This rooftop array — which spans both the school buildings and the parking lot — consists of 1541 solar panels that generate on-site electricity. The vegetation cools the roof surface, improving solar output by reducing heat-related efficiency losses in the modules. At ground level, 114 fruit trees have been planted around the school, further connecting the campus to the agricultural landscape that it is a part of.
Sustainability
The building has achieved DGNB Platinum and the German BEG 40 EE energy standard, meaning it uses 60 percent less energy than an equivalent building in Germany. The school was constructed by Georg Reisch under an ÖPP (public-private partnership) model, which includes a 25-year operational contract with contractually fixed energy consumption values that will ensure the building performs in practice as it was designed to on paper.
