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 center. The federal government launched a competition for the design; this month, Mulder Zonderland’s proposal was selected as the winner.
In the design, the architectural firm has sought for an amplifying interplay between traditional construction techniques, ecological materials and parametric design methods, Mulder Zonderland explains. According to the jury, the design is “capable of expressing the Black Forest biosphere in architecture without losing sight of functionality and cost-effectiveness.”
Urban design integration
“In a simple and compelling 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,” the jury continues. The site of the new information and visitor center is in the center of Todtnau, in the wilderness of a former metal factory.
With careful integration of the building, Mulder Zonderland ensures a partial continuation of the existing urban structure and partly a restoration of the former street scene with closed walls along Freiburger Strasse. This creates a three-sided embrace of 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 towards the sun and the program have determined 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, Mulder Zonderland explains.
The program is clearly distributed throughout the building. Via the main entrance at Rathausplatz, the foyer reaches the visitor’s heart of the building. Furthermore, there is a shop on the ground floor, a flexible divided meeting and teaching area as well as various help 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 another private entrance on Freiburger Straße. The restaurant and the associated terrace are located directly in the courtyard and have a wonderful view of Hasenhorn and the surrounding mountains, the architects say. The offices and technical areas are located on the second floor.
Generous stairs and ramps ensure smooth – and barrier-free – transitions between the various functions in the building and at the same time playfully solve the height difference between the levels on Rathausplatz and Freiburger Straße. Another route leads through the courtyard, which connects the reception and restaurant area.
Interactive wooden wall
Via the spacious foyer-cum-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 serves as the main entrance to the temporary exhibition spaces, but as a permanent, interactive exhibition space in itself.
For this purpose, 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 ecological materials of the rest of the building.
Material use and techniques
For the construction of the building, Mulder Zonderland proposes a hybrid of wood and low-cement (more climate-friendly) concrete. Reinforced concrete is used mainly for stability and where the building touches the ground. Furthermore, the construction is mainly constructed by CLT. Clay walls are also used. With the further use of wood and natural stone, the architect’s office is in line with the regional building tradition.
The rooms are heated with underfloor heating, connected to a ground source heat pump. Active cooling is not necessary, according to the architects. An optimized climate screen helps to minimize energy costs. The roofs overlooking the courtyard 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.