The recognition in 2017 of the Black Forest Biosphere Reserve as a UNESCO Biosphere Reserve meant that the state of Baden-Württemberg had to realize a new visitor and information centre. The federal government launched a competition for the design; this month, Mulder Zonderland’s proposal was chosen as the winner.
In the design, the architectural firm has looked for a reinforcing interaction between traditional building techniques, ecological materials and parametric design methods, explains Mulder Zonderland. According to the jury, the design also manages to “express the Black Forest biosphere in architecture without losing sight of functionality and cost-effectiveness.”
Urban design integration
“In a simple and convincing way, the designers manage to process and reinterpret the topography and core of the environment, so that the new biosphere center can become a striking associative of the Black Forest”, continues the jury. The site of the new information and visitor center is in the center of Todtnau, on the wasteland of a former metal factory.
With careful integration of the building, Mulder Zonderland ensures a partial continuation of the existing urban structure and a partial restoration of the former streetscape with closed walls along Freiburger Strasse. This creates a three-sided embrace of the Rathausplatz and thus a new heart for the district.
The volume itself is designed as a circular extrusion of an archetypal Black Forest dwelling. Factors such as topography, orientation to the sun and the program determine the final shape. In this way, a long cantilevered and low-hanging roof has been created to the south; on the north side, the roof goes almost back to the facade.
While the outside of the building connects with the surrounding buildings, the inside is characterized by a perfect circle. A forest garden is the striking landmark here. On the east side of the building, the existing publicly accessible connection between Rathausplatz and Freiburger Strasse is preserved, explains Mulder Zonderland.
The program is clearly distributed throughout the building. Via the main entrance at the Rathausplatz, the foyer, the visitor reaches the heart of the building. Also on the ground floor is a shop, a flexibly divided meeting and teaching area and various auxiliary areas. The exhibition space on the 1st floor can be reached via the auditorium on the east side of the foyer.
There is also a restaurant, which has a second, private entrance on Freiburger Straße. The restaurant and the associated terrace are located directly in the courtyard and have a wonderful view of the Hasenhorn and the surrounding mountains, say the architects. The offices and technical areas are located on the second floor.
Generous stairs and ramps ensure smooth – and also barrier-free – transitions between the various functions of the building and at the same time playfully resolve the difference in height between the levels on Rathausplatz and Freiburger Straße. Another route runs through the courtyard, which connects the reception and the restaurant area.
Interactive wooden wall
Via the spacious foyer-annex reception and the auditorium, the visitor reaches the central circular arcade on the first floor. The arcade is an important spatial element, explains the architectural firm; it acts as the main entrance to the temporary exhibition spaces, but as a permanent, interactive exhibition space in its own right.
To this end, the arcade will have a fifty meter long media wall of ‘augmented wood’: a new type of wooden surface behind which ‘touch sensitive’ buttons and screens are visible. When not in use, the wall subtly blends into the organic materials of the rest of the building.
Material use and techniques
Mulder Zonderland proposes a hybrid of wood and low-cement (more climate-friendly) concrete for the construction of the building. Reinforced concrete is mainly used for stability and where the building touches the ground. Furthermore, the structure is mainly built of CLT. Clay walls are also used. With the further use of wood and natural stone, the architectural office is in line with the regional building tradition.
The premises are heated with underfloor heating, connected to a ground source heat pump. According to the architects, active cooling is not necessary. An optimized climate screen contributes to minimizing energy costs. The roofs overlooking the yard are fitted with PV tiles.
The solar cell systems cover the energy needs for, among other things, the heat pumps, charging stations and general lighting. Excess generated energy is stored for use in the evening.