From the 1980s onwards, Baden-Württemberg produced an impressive portfolio of eco and solar architecture. Kim Förster combed through Stuttgart’s built environment, and visited several archives searching for the different actors, their interests and strategies and new territorialities linked to the design and use of sustainable architecture. These projects, showcasing different notions of nature and ecology, have been implemented partly as pioneer projects, partly as marketable products. In an imaginary city walk, five different types of eco and solar architecture are presented to give insights in alternate ideas of working and living typical of the region.
Institut für leichte Flächentragwerke
architect: Frei Otto
The Institut für leichte Flächentragwerke (formerly IL, now ILEK – Institut für Leichtbau Entwerfen und Konstruieren) has been housed in a tent-like structure since 1969. Founded by Frei Otto in 1964 – when he was contracted by the University of Stuttgart to experiment with new construction methods and architectural forms – the IL found a new home after Otto designed the pavilion of the Federal Republic of Germany for the World Expo in Montreal/Canada in 1967. The tent structure, which was distinguished by its lightweight construction, was originally designed as a test building, a 1:1 model for one part of the Expo-pavilion, just lifted by a 17m pylon to prove the assembly principle and construction details. Otto here proved the idea of the adaptability of his structures, their ecology and economy, especially the saving of building materials, when the tent was relocated by a crane and transformed into a non-temporary structure to serve as an institutional building. For the IL, the two symmetrical rope nets that form the main part of the tent structure were equipped with a three-layer roofing, consisting of a wooden planking covered with layers of mineral wool, tarboard, and Eternit shingles. The eye, formed by a third net covered in acrylic glass, regulated daylight and, due to increases in temperatures from the use of passive solar energy, produced moderate temperatures in the winter, yet overheating in the summer. At its base, the tent structure featured a panoramic glazing of the exterior wall. The working method and atmosphere of the IL staff is defined by an open floor plan, featuring a lowered conference and meeting space in its middle, a terraced-system with spaces for coffee breaks and lunch time, as well as another for the archival spaces, and work spaces at ground level all around. In the 1970s, the IL produced a generation of architects and engineers, who determined different approaches to eco and solar architecture, high tech and low tech.
Student Housing Bauhäusle
architects: students, supervised by Peter Hübner / Peter Sulzer
The Bauhäusle, run by the student services at the University of Stuttgart, is another experimental dormitory, which was built as an experimental self-built student project under Peter Hübner and Peter Sulzer, at the Department of Building Construction 1 on Campus Vaihingen in the southwest of Stuttgart, literally on a greenfield site. With the use of the Swabian diminutive Bauhäusle for Bauhaus, the project – tongue in cheek – of course distanced itself from the modernist doctrine. The dorm consists of a centralized communal tract with two kitchens and two bathrooms; clipped on are 30 housing units. Students in their first semester – a total of 220 – designed the overall concept, which was then realized collectively by volunteers. While the construction of the wooden frame was carried out by a local construction company, for the exterior and interior the students were able to determine both the construction as well as design details. For example, one part of the dorm is composed of four windmill-like maisonettes around a small wintergarden; for another residential unit, the support structure of which was built using two discarded tractor wheels, the principle of a Trombe wall – a collector and storage wall for the passive use of solar energy – was used. Common spaces include a cinema and a workshop. The Bauhäusle is ecological as it is constructed almost entirely of timber. In addition, grass roofs were created with old tires as a foundation in accordance with the approach of »garbage architecture.« However, the students did not work with recycled building materials, as often reported, but with new ones donated by DIY stores, companies, etc. The Bauhäusle is sustainable as future generations of students are involved in the DIY-style maintenance and continuing construction, i.e. for interior fittings and terrace extensions. Here, the incentive is that students who commit themselves to building are allowed to stay and live there for three years instead of two. While the idea for the Bauhäusle was born out of the situation of reducing the housing shortage for students, today the dorm is considered in critical architectural discourse as a prime example of practical architectural education and participatory construction. Since the Bauhäusle has been repeatedly threatened with demolition over the last few years, the city of Stuttgart recently made a six-figure sum available to renovate the dorm entirely.
Stuttgart-Vaihingen / Möhringen
architect: Gottfried Böhm
The Züblin Haus was designed as a headquarters for Germany’s largest construction company, on the southern outskirts of Stuttgart. The project, conceived and planned by Pritzker Prize winning Gottfried Böhm, was not a result of a competition, but directly awarded to the architect, whom Züblin previously had already collaborated with at the Sanctuary in Nieves, his masterpiece. The company’s HQ consists of a dual structure of two six to seven storey buildings of industrially prefabricated, yet artfully designed and colored precast reinforced concrete. In the architectural press, shortly after the building’s completion, different interpretations of Züblin Haus were offered. For example, in the Swiss journal Werk, Bauen und Wohnen – with contributions from leading German architecture critics Manfred Sack, Klaus-Dieter Weiss, and Jürgen Jödicke – the postmodern, collage-like building was read in terms of the »stubborn logic of construction;« »the affirmation of the strong image of a modern glass cathedral;« »the modular control of form and structure;« »the decorative complexity of the capitals, the domes, the stairways, and two small houses.« The center of the Züblin Haus, however, was a strikingly large glazed hall (60m long, 25m wide, and 33m high), with its footbridges, stairs, and elevators which Böhm had already included in his first draft, playing with the opposition of concrete and glass, fixed and open floor plans. For Böhm, the quality of this conservatory was that it covered an urban space connecting the two office buildings, and above two districts of Stuttgart, being located right on the border of Vaihingen and Möhringen. The conservatory’s function could be read from the socializing element, a Fourier-like symbol of finding joy in work. Yet, the 41,000sqm glass construction, similar to a botanical greenhouse, was indeed discussed in terms of construction physics, as an energy reservoir that heated water. But eventually, as a blunt ecological gesture, the conservatory instead served as a presentation of power for the Züblin company. The extraordinary typology of this office building with its glazed central space, the architectural element of the conservatory itself, is contrary to both the specific place as well as to the open landscape around. An artificial watercourse, with a small stream and small falls, breaks through the glass facade and is collected in a pond. The conservatory of Züblin Haus has been used for official events, and it became also known to Stuttgart’s population as they organized cultural events there during the summer. Züblin Haus illustrates how the construction industry, due to the economies of scale, not only acted upon production processes, but also changed the notion of nature, landscape, and ecology. It is worth noting that while the Züblin Haus won the architecture award »Beton« in 1985, in 2014 it was awarded the bronze certificate of Deutsche Gesellschaft für Nachhaltiges Bauen, which the company had joined as one of their first members.
Wohnen 2000. Experimenteller Wohnungsbau
IGA Stuttgart 93
Finally, the city of Stuttgart also decorated itself with ecology as a new trend, with an exhibition titled Ecology and the Change in Modern Life Styles, as part of the International Garden Exhibition, held in 1993 on the topic »responsible use of nature in the city.« In 1988, Stuttgart invited 27 architectural firms to take part in a competition to showcase alternatives to private homes as well as blocks of flats. As a result, between 1991 to 1993 13 projects for experimental urban living were implemented in an area around Nordbahnhof, all of which dealt with the passive use of solar energy as their subject, partly as new house groups, partly to supplement an urban block. No less than four local developers were involved: the Stuttgart Housing and Urban Development Company (SWSG); the State Development Corporation of Baden-Württemberg (LEG); the Siedlungswerk, a society for nonprofit housing and urban development; and FLÜWO Bauen und Wohnen, a housing co-operative. The teams of architects commissioned were international and came from Sweden, Norway, Finland, Denmark, Poland, the UK, France, the Netherlands, Switzerland, and Austria, as well as three from Germany. In particular, the connection of a horticultural exposition and of urban development is noteworthy with regard to the intricate relationship of architecture, ecology, and society. Moreover, it is significant that this kind of international building exhibition, titled Wohnen 2000, was sponsored by the InformationsZentrum Beton of Cologne. Also, the Swabian medium-sized enterprise Seele, which specializes in glass construction, was involved in the experimental architectural projects. With regard to the question of whether and to what extent the discipline and profession of architecture has been able to respond to broader social, economic, and environmental challenges, the project of the Dutch architectural firm Mecanoo was regarded to be of special importance by the Baden-Württemberg chapter of the Bund Deutscher Architekten (BDA). It consists of three individual towers of 13 apartments and three duplex apartments that provide for a flexible floor plan and if necessary can be divided easily; to the south, the three towers present glass facades as ecological features forming climatic buffer-zones. However, other projects of Wohnen 2000 have experimented even more with conservatories (and photovoltaics), such as the project by HHS Architekten from Kassel, where the energy concept is manifested in the architecture. The IGA was supposed to make solar architecture popular, yet the initiative back then was seen critically in the local press and on regional TV. Today, the buildings have been forgotten and are almost unknown among architectural historians.
architect: Horst Schmitges
At the end of the 1970s, early experiments with alternative designs, materials, construction took place at different university campuses in Baden-Württemberg, e.g. the dormitory for the University of Stuttgart-Hohenheim, designed by Horst Schmitges and built from 1977 to 1979 on behalf of the student services by a private developer is a complex of six three- to four-story buildings with a total of 158 student dormitories, conceived as green roofed earth mound buildings on a southern slope and arranged in groups of two around small basins. With regard to both construction physics as construction ecology, the dorms represented the state of the art of eco and solar architecture. While the buildings were completely covered with soil on their north, east and west sides, making use of the topography, the windows were all oriented only to the south. Here, the use of passive solar energy has been tested and evaluated, in terms of a manual, electric, or fully automatic control of shutters. Costs were saved as only a few windows were allowed to be opened; additionally, energy was saved by a high thermal insulation of roofs and walls as the use of heat recovery from all ventilation systems. The ecological concept by Gernot Minke, a former associate of Frei Otto at the IL at the University of Stuttgart-Vaihingen, who has then directed the Research Laboratory for Experimental Building at the University of Kassel since 1974, where he experimented with clay as an alternative building material, included the creation of biotopes to compensate for temperature differences between day and night, the activation of a spring, to provide a natural water supply, and the greening of the roofs and façades. All surfaces remained unsealed, thus sparing a rainwater connection to the sewer. While the earth mound dorms back in the 1980s were primarily presented and discussed in the architectural press in detail by Schmitges and Minke themselves, today, the city of Stuttgart is priding itself with their environmentally sound and healthy construction, as the office of environmental protection of the city cites Stuttgart-Hohenheim as spotlight no. 1 in a tour on urban climatology.
different locations in Baden-Württemberg
architectural developer: Archy Nova / architect: Jürgen Carstens
SolArc was first developed in 1991 by the architecture firm and developer Archy Nova from Stuttgart as an alternative, green, yet marketable product. Archy Nova under the management of Gerd Hansen – a former student of Frei Otto, who had first established a DIY store for ecological building materials in the 1980s – entered the market on the premise of offering a sustainable, holistic solution to living. The SolArc, designed in collaboration with architect Jürgen Carstens, is offered as a low-energy house in different sizes and designs, which serves luxurious as well as radical notions of living. First realized in Bönnigheim, SolArc was built on a larger scale of nine houses in 1993 in the residential estate »Auf der Steig« in Donaueschingen and was promoted by the Ministry of Finance and Economics Baden-Württemberg as a demonstration project. As one of the latest product innovations on the housing market, SolArc – initially ridiculed – is a tunnel-shaped, two-story wood framed house with semicircular cross section, a passive solar house construction, that in terms of home technology as well as of material use, complies with ecological principles. Due to the prefabrication of the supporting structure, the roof as well as the north and south facade made from untreated larch, it can be built inexpensively. In terms of ecology and energy the earth mound is considered state-of-the-art, since the backfill of soil from 30cm to several meters reduces heat transmission. A solar panel on the front heats the domestic water and is advertised as serving as sun and rain protection. A reconception of SolArc from the mid-2000s shows the development of the construction and building services, now including a heat recovery ventilation system. Accordingly, Archy Nova filled an economical and ecological niche – ranging from the holiday home (75sqm) to an unconventional villa type (180sqm) – with a modern interior design, an open floor plan, and direct garage access on request. What is not included in the price are the bottom plate made out of concrete and the interior design. In brochures by Archy Nova, it is noted that the SolArc could also be built as an eco-settlement, with the argument that this would be supported by most municipalities due to the attention effects. In addition, the green product is advertised for sale for dropouts all over Europe in an autonomous version with a completely odorless composting toilet, as they were used in the 1970s; a rainwater and gray-water recycling; and solar power production for their own consumption. SolArc was covered by the local press, featuring family stories, and on television as a docusoap. In general, earth mounds are quite a novel, yet also archaic building typology that are inhabited not only by moles or hobbits, but by the middle class. However, they also combine different environmental and political demands, demonstrated by the fact that they were emphasized both by the BUND in their publication Ökologisch Bauen und Renovieren (2005) and by Die Linke in a report on Das zukunftsgerechte Einfamilienhaus (2009). The authors here presented earth mounds as the most advanced state of building science, making use of a moral political argument as they demand that only passive houses or earth mounds should be built in the future.
architect: Werner Sobek / SchwörerHaus KG
The latest flagship of Stuttgart’s art of engineering is a high-tech building, designed by Werner Sobek, called B10. It is located in the protomodern Weißenhofsiedlung, built in 1927. This, the world’s first active house, is characterized by the very latest home technology, as it was developed and is now being evaluated by the ILEK in Stuttgart-Vaihingen. It includes a sophisticated energy concept and a self-learning building control system. The project website states that B10 »generates twice as much energy as it actually requires,« the special trick being that the house, functioning as a power station, supplies renewable energy to the Weißenhofmuseum (originally designed by Le Corbusier). Completely white, B10 »coolly« demonstrates superiority over the icons of modernism. It has attracted criticism since, architecturally speaking, the smart house has not that much to offer. This assessment seems fair since Sobek here was not dealing with the architecture per se in as much as B10 is based on the mini-house scheme of the Swabian prefabricated house manufacturer SchwörerHaus KG, based on the FlyingSpace module that can be combined as needed. The concept of a smart house entails living as a single person or couple in an energy efficient and drastically slimmed down way, in the smallest possible space, as described by the press and publications, such as Monocle or Wallpaper, or even the catalogs for prefabricated houses. And if that is not enough symbolism, B10 – like the city of Stuttgart and the province of Baden-Württemberg in general – is based on the premise of (auto)mobility as part of the research project on »Schaufenster Elektromobilität.« A Smart (apparently the electric version, the petrol-powered version still consumes 4.5 liters per 100 km) – a car brand produced by Daimler, whose main sales offices are in Böblingen, south of Stuttgart – is demonstratively parked in front of the house or even in the house. However, B10 looks like a fortress which one can retreat into if the outside world becomes too much. The entire front facade is designed as a drawbridge, which can be pulled up in case of attacks by the enemy. The concept, design, implementation, and suggested use thus demonstrate that B10 has no relation to the city whatsoever. Instead, the box is contemporary and flexible, easy to disassemble and relocate again. Despite the reduction to the bare essentials: this Stuttgart-like representation of the slim fit, more or less self-sufficient detached house of the neoliberal era nevertheless looks truly grim, without the slightest idea of what sustainable urbanism could constitute.