German architectural studio TCHOBAN VOSS Architekten has designed an ensemble of two seven-storey timber-hybrid office buildings in the Schöneberg district of Berlin, Germany. Built on a 10,100-square-metre site near Berlin Südkreuz station, the 32-000-square-metre “EDGE Suedkreuz Berlin” includes the largest free-standing timber-hybrid building in Germany. In 2022, the project was certified as Germany’s most sustainable building by the German Sustainable Building Council (DGNB). This landmark project showcases the achievements of large‑scale, low‑carbon, and biophilic architecture.

The Carré and Solitaire buildings

The EDGE Suedkreuz Berlin complex is located in Schöneberger Linse, an emerging urban quarter between Berlin Südkreuz and Schöneberg stations. Schöneberger Linse is a mixed-use and sustainable urban regeneration initiative that includes residential, office, cultural, and commercial spaces. The larger of EDGE Suedkreuz Berlin’s two buildings, the 20,000-square-metre Carré building, is a four-wing structure with an irregular trapezoidal footprint arranged around an atrium.

The Carré building houses the German headquarters of the Swedish multinational power company Vattenfall. The smaller building, known as Solitaire, is an elongated structure that continues the line of the larger Carré building’s facade. Solitaire has a mix of tenants, retail, and dining spaces. The two freestanding buildings form a street front facing Hedwig-Dohm-Strasse and create a new urban plaza in the direction of Südkreuz Station.

Interior architecture

The Carré building’s two-storey entrance lobby is accessed via the new urban plaza. With a clear height of seven metres, the lobby opens onto an impressive 26-metre-high atrium. The light-filled atrium’s roof structure is engineered with specially developed metal nodes, ETFE foil, and filigree wooden components. This design ensures greater lighting in the atrium below due to the narrower cross-sections.

The atrium’s architectural highlight is the inclusion of four wooden tree-like columns, each with differing heights that rise skywards towards the roof. These columns branch into platforms and are connected by zigzagging stair bridges that lead to office areas. The largest column rises to 14.87 metres in height and has a platform with a diameter of 6.20 metres. The smallest column has a height of 4.28 metres and a diameter of 7.20 metres. The atrium’s dining and community spaces add to its vibrant quality.

A fifth-floor sky lounge, featuring panoramic windows and a spacious external terrace, connects to the atrium via the stair bridges. Each of the Carré building’s internal corners houses a building core with a safety staircase and elevators.

The building’s floor-to-ceiling office windows, glazed entrance area, and large panoramic windows in the lounge all contribute to the abundance of natural daylight. The profusion of wood, light, and greenery fosters a biophilic, nature-inspired environment. 

The Solitaire building also has a two-storey entrance lobby, with a clear height of seven metres, that is accessed via the new urban plaza. The ground floor houses retail and dining spaces, while offices are located on the second to seventh floors. In this smaller building, wood is also a ubiquitous architectural and design element. A rooftop lounge features a landscaped outdoor space.

The interior architecture of EDGE Suedkreuz Berlin was realised by Berlin-based architectural studio de Winder Architekten.

Flexible and reusable building design

The Carré and Solitaire buildings were designed with flexible, modular floor plans on all levels. Deconstruction was a core concept from the project's outset, and circularity was thus integrated into architectural planning at an early stage. To ensure the EDGE Suedkreuz Berlin complex is flexible and reusable, TCHOBAN VOSS Architekten avoided load-bearing interior walls and planned room heights of at least three metres. Staircases have been thoughtfully arranged and a clever system of zoning for all technical building equipment was introduced.

The two buildings share a basement garage, with 218 e-mobility spaces for tenants. A bicycle room houses around 100 bicycle spaces, including those for e-bikes, with an additional 32 exterior spaces.

The office areas, as well as the associated ancillary and circulation areas, are barrier-free. All outdoor areas are also designed to be accessible.

Sustainable facades

The facades of the Carré and Solitaire buildings have a regular grid made up of weather-resistant glass-fibre concrete panels. This grid is formed by horizontal strips and vertical elements in different colours. The colours and dimensions of the two buildings create a direct architectural dialogue. Carré’s grid consists of horizontal strips in a Sahara sand colour and vertical elements in terracotta. The reveals are visually distinguished by their silver-grey colour. Solitaire’s grid consists of horizontal strips in Sahara sand and vertical elements in silver-grey.

The facades of both buildings are defined vertically through the use of pylons, while glass-fibre pilasters visually reinforce the socle section.

The sustainable and recyclable facade elements of the two buildings weigh just 30 kilograms per square metre. The thinly ground cement top layer of the facades absorbs carbon from the air, providing a decarbonising effect.

The architects selected MicroShade® as a sustainable solution for solar shading in the structural glazing areas of the buildings: one-storey for Solitaire and two-storeys for Carré. This choice ensures effective solar protection without compromising on temperature, daylight, or views. 

Hybrid-timber construction

The construction of the EDGE Suedkreuz Berlin complex prioritised reducing its carbon footprint, particularly by minimising the overall weight. The project also prioritised sustainable materials that are recyclable in accordance with the Cradle to Cradle principle.

Prefabricated wooden modules were used for walls and ceilings, ensuring a precise and efficient construction process. Wall elements were made in the German town of Neuruppin, while ceiling elements were manufactured in the German municipality of Lemwerder and the town of Henningsdorf. The project used a total of 1,190 wood-hybrid ceiling elements, supported by 1,280 glulam facade supports, and 445 multibox wall elements.

The predominant use of wood benefits the health and well-being of users and visitors across both buildings. 

A modular timber–concrete hybrid construction system developed by CREE Buildings was used in EDGE Suedkreuz Berlin. By combining renewable timber with structurally targeted concrete, the project achieved a reduction in its embodied carbon emissions by up to 50 percent per square metre of floor area compared to conventional reinforced concrete construction.

Sustainability certificates

EDGE Suedkreuz Berlin received the DGNB Platinum certificate with a score of 95.4 percent for sustainability performance, the highest ever achieved in Germany. In addition, the complex was certified with DGNB Diamond for its outstanding design and architectural quality. The project has received a WELL v2 Platinum certification.

From 2019 to 2022, project developer EDGE realised the new German head office for 1,650 employees of Swedish energy company Vattenfall at Südkreuz Berlin.

The new build based on designs by Tchoban Voss Architects is the largest completed wood-hybrid building in Germany and was awarded the highest DGNB certification as the most sustainable building in Germany, as well as the “DGNB Diamond” for the excellent design quality of the overall construction and the interior spaces.

The innovative office building is located on a public square in the immediate vicinity of the important transport hub Berlin-Südkreuz, and is part of the “Schöneberger Linse” city development project. Four office blocks of seven storeys are arranged around a central inside courtyard with a transparent roof, known as the atrium. The stairways and lifts are positioned in the inner corners of the buildings.

The de Winder architectural office worked alongside EDGE from 2017 onwards in the search for a suitable user for the property, and subsequently took over the planning and design of the approx. 22,000 m2 workspace on behalf of Vattenfall. The sustainable, innovative orientation of the building and its future tenant were a perfect match and provided the basis for the development of the new office spaces.

In two series of workshops with employees from the various departments, solutions were prepared together for the structure and the possible uses presented by the floor plans. The size and location of the work spaces, meeting rooms and quiet areas were discussed intensively and implemented. The design of the team areas is also the result of a participative process with the Vattenfall employees. Specific use requirements were discussed, the arrangement of work islands in different constellations were defined by representatives of the departments themselves, and these were then incorporated into the planning to meet the needs of the target groups. In this way, bespoke work areas with variable atmospheres and use constellations were created.

With different colour schemes for individual zones, the team areas make it easier to navigate within the building. Each “team base” – which the employees have also named their “bus stop” – is customised by its team, thus boosting the feeling of identification. The workplace areas are combined with integrated phone booths and meeting boxes, quiet areas for relaxing or working in solitude, zones for informal meetings, storage areas and locker units.

Because the overarching idea is that of a non-territorial workplace concept, all employees are free to choose any place within the building while also being assigned to the “team bases”. Each storey is additionally equipped with two team kitchens, including diner area and coffee bases, that look out into the atrium, as well as separately bookable collaboration centres.

The design and zoning of the atrium, with its four “trees” – tree-shaped supports – was one of the biggest challenges. The overall goal was for the space to function as a restaurant and a representative meeting place, to invite the employees to move from storey to storey, to offer seating arrangements for casual meeting and co-working situations, and to provide a communication centre.

The structure of the ground floor area arose from the differentiation of individual horizontal and vertical zones that offered a variety of qualities to occupants. A space-defining modular seating landscape delineates the three different areas. The space as a whole is thus characterised by the custom furnishing concept with bespoke fitted units such as tables and benches in the restaurant, bistro tables at seating islands in the coffee area, and functional table configurations in the co-working area.

The zoning is harmoniously enhanced by the intensive, integrated green area concept, which adds to the feel-good character of the individual areas. To optimise the acoustic requirements for the 26 m-high atrium, absorbing surfaces were integrated into the seating landscape and the free-standing room dividers. The varied heights of the fitted units create a range of perceptions and vistas, thus utilising the impressive volume of the atrium.

The four trees, which connect the individual storeys on a variety of levels, offer comfortable lounge areas for relaxing or working in. Impressive views and spatial axes open up from vantage points along the stairway composition, and reveal the interaction between the interior design and the architecture.

The semi-public space of the atrium is adjoined on the ground floor by a separate conference zone with a coffee bar and an adjacent creative zone with project rooms. Four smaller conference rooms are available here along with a larger dividable conference room that can be unified if required to provide seating space for up to 100 people. The six project rooms are intended for special creative processes whereby teams can meet and work intensively on solutions over several days if necessary.

A further highlight is the Skylounge on the 5th floor, accessed directly from the highest of the four trees and with an open view down into the atrium. The Skylounge was also designed as a multi-functional space with mobile seating cubes for event situations on one side, and a lounge with a bar on the other. A centrally-positioned meeting box island divides the room and offers a space for discreete conversations or phone calls. The adjacent furnished outside terrace with a view of the new Südkreuz train station is ideal for relaxing and exchanging ideas.