Located in the area between Sachsendamm and Berlin Südkreuz S-Bahn train station in Schöneberg, a new mixed-use complex, EDGE Suedkreuz Berlin, was completed last month by Berlin-based architect Sergei Tchoban and his firm Tchoban Voss Architekten with additional offices in Hamburg and Dresden. The complex comprises two freestanding structures—a larger Carré Building and a smaller Solitaire Building. Together they occupy their own block. The pair is now the largest hybrid-timber complex of buildings in Germany and one of the largest in Europe.
EDGE Suedkreuz Berlin is a part of a larger development, a new urban district in Berlin’s Schöneberger Linse to include housing, offices, culture, and commerce. In addition to the use of sustainable timber-hybrid building materials, the key idea here was to provide employees with various environments with a mix of open and informal meeting areas to complement more conventional office spaces. And the project’s heart—the airy atrium—has succeeded in creating a memorable space with a uniquely warm atmosphere.
The EDGE Suedkreuz’s both buildings are seven-story structures. The Carré Building (the Quad) is a trapezoidal quadrangle with a covered atrium and the Solitaire building is a traditional rectangle in its plan. The two buildings combined provide 32,000 m2 of floor space. They form a strong street front along Hedwig-Dohm-Straße and define a new urban plaza with green spaces and seating between the two structures. A two-story entrance lobby of the Carré Building faces the plaza and leads to the centrally positioned immense atrium. This strictly gridded volume has a ceiling height of 26 meters, culminating in a transparent ETFE foil roof carried by a system of wooden trusses. The continuous floor-to-ceiling windows in the offices, the glazed entrance area, and the large panoramic window in the building’s lounge additionally contribute to the abundance of daylight.
The atrium, the most emblematic part of the project, is dominated by four tree-size and mushroom-shaped forms of different heights. They grow skywards under the foil roof as if inside a greenhouse. At ground level, green islands of tranquillity group themselves around these mushrooms’ stems. The atrium is additionally enlivened by community and food areas, while the hats of the mushrooms carry round platforms for recreation. The tallest of them reaches almost 15 meters and has a platform with a diameter of 6.20 meters. The shortest mushroom is almost 4.5 meters high with a diameter of 7.20 meters. These four compelling structures are linked by bridges and stairs to connect each other and office floors. They provide an effective network of communications. The fifth floor has a sky lounge with panoramic windows and a spacious external terrace. The lounge is openly linked to the atrium and, like the offices, may be reached via the “mushroom stairs.” Many elements of the building—columns, beams, windows, doors, railings, and other surfaces—are made of wood and are prominently visible, adding an enriching liveliness to the complex by bringing nature into individual spaces. The building is an open ecological system. The clear symbolic inspiration for its architecture is the forest: wood defines this building’s character. Additional exit stairs are enclosed within the building’s corners. Parts of the roof are extensively landscaped.
The Solitaire Building also features a two-story entrance lobby. Floors 2 to 7 contain offices. The ground floor houses gastronomic, commercial, and retail spaces. As in the case of the Carré Building, wood is ubiquitous here. And just like in the case of the first building, the Solitaire is entered from the new urban plaza. Vertical access is by means of a central core with an exit staircase and two elevators. The landscaped area on the building’s roof has a garden-like quality. Both buildings have a flexible modular plan on all levels. Open-plan layouts encourage communication and include retreat areas, as well as conference rooms and special zones such as lounges and team kitchens for informal interaction. Additionally, the two buildings share a basement garage for 218 cars and a bicycle room to store 300 bicycles; there are additional bicycle parking spaces along the adjacent streets.
The façades have a regular grid, consisting of sustainable and weather-resistant glass-fiber concrete panels. The grid is articulated by horizontal strips and colored vertical panels. Glass-fiber pilasters visually reinforce the double-height ground floor. The rhythmic façades have a restrained color scheme, which has been chosen individually for each of the two buildings. In the case of the Carré the colors are Sahara sand for the horizontal strips and terracotta for the vertical structures. The reveals are visually set apart by their silver-gray color. The Solitaire has corresponding colors: Sahara sand for horizontal elements and silver-gray for vertical elements. The two buildings engage in a direct dialogue with one another through their geometry, graphics, proportions, and relationships between various design elements. The glass bays with fixed glazing and MicroShade solar protection additionally accentuate the façades; these are one-story in the case of the Solitaire building and two-story in the case of the Carré. The remaining windows are fitted with anti-glare protection and external sun protectors.
The wooden elements of Hybrid-timber construction, including wall and ceiling modules, were prefabricated, assembled, and adjusted on site. This strategy ensured a precise construction schedule and time efficiency. The wall elements were made regionally in Neuruppin, while the ceiling elements, were produced in Lower Saxony. Altogether, there are 1,190 wood-hybrid ceiling elements carried by 1,280 glulam façade supports and 445 wood-frame wall elements with a total area of 16,000 m2. Wood can be spotted everywhere in the interior spaces, which makes an important contribution to creating a healthy indoor climate for users. Wood also possesses a high heat-storage capacity but limited thermal conductivity. Existing heat is retained for longer in the room than heat from other building materials. The delayed cooling reduces the amount of energy required. Wood is also lighter and more energy-efficient to transport than mineral-based building materials. This project used approximately 3,350 m3 of FSC-certified spruce—a total of approximately 1,200 trees.
According to the architect, the intelligent use of both wood and concrete in this hybrid construction method saved up to 80% of CO2 per square meter of floor area. Low construction weight, shorter construction times, and long-term durability are other advantages of this construction method. The construction materials used in the EDGE Suedkreuz are extensively recyclable using the principle of cradle-to-cradle recycling. Reinforced-concrete construction elements were kept to a minimum, being used for fire compartment separation or to stiffen the building. Wood and hybrid-timber elements were installed as the load-bearing framework, especially in the interior; concrete was used for constructing the foundations and basement. The wooden supports and beams carry the building’s overall vertical loads. Since a hybrid-timber building weighs only approximately a third of a conventional building, the foundation slab used here is approximately 30% thinner than conventional examples.
The system of staircases in the atrium of the Carré has been designed as a metal structure in order to avoid the excessive consumption of materials and bulky wooden trusses. The use of specially designed metal nodes, ETFE foil, and filigree wooden components helped to reduce the weight of the roof. Its slender cross-section ensures a high level of illumination in the atrium below. At the same time, the roof structure withstands the most extreme wind loads in the area since each rod can carry not just tensile but also compressive forces. Throughout the project, the smart use of high-tech components and abundance of natural materials—all put together in the most generous settings—achieved a desirable result of creating an elegant, responsive, and responsible working environment.
Building Data:
- Address: Hildegard-Knef-Platz 2 and 3, 10829 Berlin
- Client: EDGE, Berlin
- Floor area: 32,000 sqm
- Completion: May 2022
- Service stages: 1-4, general specifications and creative/design management, BIM (building information modeling)
- Architect: Sergei Tchoban
- Project partners: Stephan Lohre, Karsten Waldschmidt
- Team: Julia Angelstorf, Lev Chestakov, Giorgia Fontana, Ulrike Graefenhain, René Hoch, Anastasia Kapustina, Valeria Kashirina, Birgit Koeder, Achim Linde, Fabiana Pedretti, Dennis Petricic, Manuela Peth, Soeren van Ost, Fabio Prada, Anja Schroth, Katharina Stranz, Carolin Trahorsch
- Collaborating architects: Service stage 5: granz + zecher architekten GmbH, Berlin; external employees: Carsten Heidtmann, Peter LeRoy, Claudia Zecher
- General contractor: ARGE SXB, Suedkreuz Berlin ZECH Bau GmbH, CREE Deutschland GmbH, Rhomberg Systemholzbau GmbH represented by ZECH Bau GmbH, Berlin
- Project management: SMV Bauprojektsteuerung Ingenieurgesellschaft mbH, Berlin
- Landscaping: service stages 1-4, hochC Landschaftsarchitektur, Berlin; service stage 5, granz + zecher architekten GmbH, Berlin
- Structural engineering: Happold Ingenieurbuero GmbH, Berlin; BIT Buero fuer integrale Tragwerksplanung GmbH, Berlin
- Building technology: Happold Ingenieurbuero GmbH, Berlin
- Interior design: de Winder Architekten GmbH, Berlin
- Façades / glass-fibre concrete panels: Rieder Group, Maishofen, Austria
- Façades / wall modules: Opitz Holzbau GmbH & Co. KG, Neuruppin
- Hybrid ceilings: BWE-Bau Fertigteilwerk GmbH, Lemwerder, thomas allton GmbH, Henningsdorf
- Solar-shading glazing: MicroShade A/S, Glostrup, Denmark
- Roof construction Carré-Atrium metal: Biedenkapp Stahlbau GmbH, Wangen
- Roof construction Carré-Atrium Wood / ETFE foil: Temme // Obermeier GmbH, Rosenheim
- Photography: Ilya Ivanov
- Certificates: The hybrid-timber construction method made it possible to obtain DGNB platinum (diamond) and WELL Core & Shell Gold (platinum) certification
