Nothing ventured, nothing gained. A wise old saying, and one that proved to be totally true for the developer Edge. When Edge first started planning the Edge Suedkreuz office complex in 2019, the hybrid timber construction it plumped for was still new territory and an area few had detailed experience in. Fast forward to October 2022 and the project has been officially confirmed as the highest-scoring development ever certified by the DGNB. Based on their feedback, the users of the office complex can attest to this – on all fronts. The bold undertaking was certainly worth it.
Probably now the biggest hybrid timber building complex in Germany, Edge Suedkreuz excels on all levels. With a score of 95.4% on the ‘total performance index’, the development notched up the highest rating to date for new buildings certified by the DGNB.
“Sustainability was an integral element early on in the project, like a sapling regularly nurtured with ideas, aspirations, passion and an awareness of quality – the DGNB system was embraced and embodied as part of a joint effort.” Thomas Kraubitz (senior DGNB auditor, Buro Happold)
An independent Commission for Design Quality also petitioned for the project to receive a certificate in DGNB Diamond. This allowed Matthias Burkart (4a Architects), Prof. Amandus Samsøe Sattler (Ensømble Studio Architecture) and Boris Schade-Bünsow (Bauwelt) to pay tribute to another aspect of sustainability of the buildings: the truly outstanding longevity of the design.
Playing to the properties of materials in the interest of sustainability
The timbers and reinforced concrete used for the chosen hybrid construction are a perfect match for one another thanks to their complementary properties: wood delivers structural stability, while the reinforced concrete adds rigidity and offers fire protection. With over 3300 cubic metres of timber used for the complex, wood accounts for the lion’s share of materials and this has a positive effect on both the indoor climate and the accumulative energy balance of the buildings. Compared to conventional construction based on reinforced concrete, CO2 savings of roughly 80% are anticipated per square metre of floor space. A modular approach was adopted for the architecture of the complex, with a large proportion of prefabricated elements. This also had positive impacts on the building process and road traffic during construction.
“EDGE loves wood. Not only does it allow us to avoid CO2 emissions in the production of construction materials, as was the case with EDGE Suedkreuz, but wood also sequesters pollutants during the lifetime of a building.”
Coen van Oostrom (Founder & CEO EDGE)
Working in an illustrious location
Tchoban Voss architects were responsible for the design of the development. Built on a plot measuring 10,000 square metres, along the edge of an urban development zone called Schöneberger Linse in the south of Berlin, the complex comprises two seven-storey office buildings. Named Solitär and Carré, together they form a city plaza leading to Berlin’s third-largest long-distance train station, Südkreuz. The plaza, Hildegard Knef Platz, features wooden platforms, seating areas and a variety of green spaces, offering an open invitation to people working in the complex – as well as passers-by – to hang out and relax.
Both buildings are accessible from the plaza. The smaller Solitär office block has been rented out to Q Cells, a provider of photovoltaic systems. The ground floor will house restaurants and catering, as well as retail outlets. The Carré building is now home to the new German headquarters of Vattenfall, the Swedish power company.
Real value comes from within
The façade comprises a uniform grid clad with fibre cement panels, providing little indication of the innovative methods used to construct the buildings. It’s only on entering the edifices that you surmise the ubiquity of the main material in the building: wood. The unmistakably welcoming aesthetics of the architecture are reflected in exposed structural timbers, ceiling-high windows, and wooden doors and handrails.
The first sight to greet the 1600 Vattenfall employees on entering the 20,000-square-metre Carré building is the central atrium. Overhead, the ETFE cushion roof provides ample daylight to all areas of this space. Covering 1600 square metres, the 26-meter-high atrium is dominated by four columns – branching out like trees at different heights.
Connected by walkways and stairs, the awe-inspiring superstructure offers a channel of communication to all areas of the building. As such, the spectacular walkways form the shortest links between the individual floors.
Each upright is crowned by a platform measuring up to 7.20 metres in diameter, offering places for informal meetings. The staircase sculpture starts on the ground floor in the catering and conference areas, ending on the fifth floor with a skylounge in front of a covered balcony that looks out across the city towards the train station.
Contemporary work on many levels
The experience savoured in the atrium continues in the office areas. Ceiling-high windows deliver an open view of the outside, offering further visual references to the connections between floors. If areas need to be used in a different way, the modular floor plan offers plenty of flexibility to make adjustments.
The office areas are totally in tune with the concept of flexible working. Each floor offers open-space areas of different sizes, individual workstations for more focused work, meeting rooms for teams to work in and kitchenettes for informal meet-ups. Depending on their current priorities, staff can seek out suitable areas within their workspaces, which were designed with sustainability in mind.
“Edge Suedkreuz isn’t just any old building, it was – and for me remains – a prototype for a new way of thinking. It’s a way of thinking that looks to the future, in which the rational merges with the artistic and the affective. Each material only occupies the space it was destined to. The lightweight elements that were aimed for in the building entail the use of different kinds of materials, which especially means timber hybrid construction and a reduction in CO2 emissions. Prefabricating building components, and the potential to make repeated use of them, provide for a sustainable building system, and the inspiring areas produce an example for the office space of the future.”
Sergei Tchoban, TCHOBAN VOSS Architects