The new building of the employment center has appeared in the very center of the city, on the Altmarkt square, where market trading is still taking place six days a week. Oberhausen is a relatively young city, formed in the 19th – 20th centuries as a major center of the coal mining, metallurgical, and machine-building industries. In the course of its growth, it included the ancient castles and villages that were located here, but, of course, did not become ancient itself.
However, it still has a historic center, just around the market square. At the end of the 20th century, this center fell victim to a deep crisis, into which the Ruhr region, which was completely dependent on heavy industry, plunged. In addition to the general economic decline, this part of Oberhausen was negatively affected by the creation in the 1990s of the "New Center" on the former territory of the coal and metallurgical concern Gutehoffnungshütte - with the largest Centro mall in Germany, amusement parks and other "points of attraction".
The idea to connect the administrative building and the “city farm” came from the city authorities as part of a program to revive the old city. The first such project in Germany was developed in cooperation with the Fraunhofer Institute UMSICHT based in Oberhausen: it deals with technologies in the fields of the environment, life safety and energy, including the topic of integrating agricultural production into buildings.
In 2016, the competition for the project of this "hybrid" was won by the Kuehn Malvezzi bureau, which emphasized the unusual combination of two functions, an employment center and a greenhouse, by choosing the material. The office part has got clinker facades of a cold dark red hue. Stacked masonry emphasizes its role as a cladding material rather than a "building" material, while brick is also a tribute to the local context. The main attractions of Oberhausen, the town hall, the main warehouse Gutehoffnungshütte designed by Behrens, which has now become a museum storehouse, and other notable structures - exactly brick buildings of the early 20th century.
Compared to clinker facades, the almost seamless continuation of the greenhouse, which covers the entire roof area, seems especially light and permeable. This feeling is shared with her and the "hanging garden" leading to her from ground level. "Trellis", as the architects call it, accommodates a staircase, a freight elevator and floor platforms with benches. It connects the market square, where vegetables and fruits are sold, with the place of their production - a greenhouse. There is also a roof terrace with panoramic views of the city.
The greenhouse, designed with Haas Architekten, grows lettuce, herbs and strawberries using the ebb-and-flow method, as well as water-filled containers and pyramid-like beds. The greenhouse is owned by the municipality, which regularly opens its doors to the general public and sells its products. The Fraunhofer Institute is also involved in research, and the hall on the fourth floor is used for seminars and meetings.
The greenhouse and vertical garden spawned a number of eco-components of the project. So, the air saturated with carbon dioxide and heat from the ventilation system of the office part is very useful for plants and therefore enters the greenhouse; rainwater is collected to irrigate them, while gray water from shells is used to irrigate ornamental plantings in a vertical garden and in cisterns.
The courtyard inside the U-shaped building of Kuehn Malvezzi is landscaped, taking into account its perception from the upper floors and the roof - like a pointillist painting. Compacted gravel forms the landscape; dry and wet areas are separated in height up to 60 cm. There are bushes, perennials, ferns and grasses, as well as three irgi. This garden faces the glazed lobby of the employment center, which contrasts with the clinker outside with its concrete surfaces.
The completely permeable "trellis" of the vertical garden on the lower level includes Japanese grapes, common hops, Chinese wisteria and petiole hydrangea: they are rooted at ground level. More delicate species of lianas grow higher: aquebia five, acute actinidia, mountain clematis. The landscape part of the project was handled by the Berlin bureau atelier le balto.
The project is based on a modular principle: vertical parts of the structure made of galvanized steel are used in the window frames of the employment center, in the frame of the greenhouse and "trellis", the platforms of which are horizontally precisely coordinated with the window sills.
