Location
Düsseldorf, Germany
Typology
Commercial
Office
Mixed-use
Year
2017-2020
Status
completed
Client
CENTRUM Group, Düsseldorf and B&L Group, HamburgKö-Bogen Düsseldorf
Size
office building 41,370 m² GFA | underground parking garage 23,00 m² GFA | 26,6 ha site area
Read more
Architecture as Part of Natural Systems
Kö-Bogen II reflects ingenhoven associates’ supergreen® philosophy—an integrated design approach that understands architecture, landscape and climate as interconnected systems. Located in the heart of Düsseldorf, the project forms the final piece of a comprehensive urban transformation, reconnecting the city centre with the adjacent Hofgarten and redefining the relationship between architecture, public space and nature.
For decades, the area was dominated by traffic infrastructure, creating a physical barrier between the historic park and the surrounding urban fabric. The relocation of traffic below ground created the opportunity to reshape the public realm, establish new connections and return valuable space to the city. Kö-Bogen II plays a central role within this transformation, acting not as an isolated building but as part of a larger urban landscape.
Its defining characteristic is a living architectural envelope. Hornbeam plants shape the inclined roof and façade surfaces, forming a continuous layer of vegetation that has been integral to the design from the very beginning. Rather than serving as an applied green façade, the planting becomes part of the architecture itself, contributing spatial, environmental and climatic performance while continuously evolving with the changing seasons.
Architecture is therefore understood as a dynamic system rather than a static object. Light, weather, seasonal change and plant growth continuously influence the perception and performance of the building. Time becomes an architectural dimension, allowing the project to evolve throughout its lifetime instead of remaining fixed from the moment of completion.
This understanding lies at the heart of the supergreen® philosophy. Sustainability is not treated as an additional layer of technology, but as a fundamental design principle in which architecture actively participates in natural processes and contributes to the long-term ecological, social and spatial quality of the city.
Location
Düsseldorf, Germany
Typology
Commercial
Office
Mixed-use
Year
2017-2020
Status
completed
Client
CENTRUM Group, Düsseldorf and B&L Group, HamburgKö-Bogen Düsseldorf
Size
office building 41,370 m² GFA | underground parking garage 23,00 m² GFA | 26,6 ha site area
Read more
Reconnecting the City. The significance of Kö-Bogen II extends beyond the building itself. It is part of a wider urban strategy that transforms former traffic infrastructure into a network of public spaces with a stronger relationship to the surrounding landscape. By reconnecting the city centre with the Hofgarten, the project restores historical urban connections while creating new opportunities for movement, interaction and public life. Towards Schadowstraße, the building presents a transparent and active urban edge. Towards Gustaf-Gründgens-Platz and the Hofgarten, the architecture gradually transforms into a planted landscape whose inclined surfaces dissolve the traditional boundary between building and park. The project responds to these different urban conditions while establishing a coherent spatial identity across the site. Vegetation also performs an important urban role. It softens the scale of the building, changes its appearance throughout the year and creates a visual dialogue with the mature trees of the Hofgarten. Rather than competing with the surrounding landscape, the architecture extends its presence into the city and contributes to a more continuous green urban fabric. Urban quality is defined not only by built form, but by the relationships it creates. New pedestrian connections, public spaces and visual links encourage movement through the site and strengthen the connection between the surrounding neighbourhoods. Kö-Bogen II demonstrates how architecture can contribute to a more resilient, people-oriented and climate-responsive city.
Reconnecting the City. The significance of Kö-Bogen II extends beyond the building itself. It is part of a wider urban strategy that transforms former traffic infrastructure into a network of public spaces with a stronger relationship to the surrounding landscape. By reconnecting the city centre with the Hofgarten, the project restores historical urban connections while creating new opportunities for movement, interaction and public life. Towards Schadowstraße, the building presents a transparent and active urban edge. Towards Gustaf-Gründgens-Platz and the Hofgarten, the architecture gradually transforms into a planted landscape whose inclined surfaces dissolve the traditional boundary between building and park. The project responds to these different urban conditions while establishing a coherent spatial identity across the site. Vegetation also performs an important urban role. It softens the scale of the building, changes its appearance throughout the year and creates a visual dialogue with the mature trees of the Hofgarten. Rather than competing with the surrounding landscape, the architecture extends its presence into the city and contributes to a more continuous green urban fabric. Urban quality is defined not only by built form, but by the relationships it creates. New pedestrian connections, public spaces and visual links encourage movement through the site and strengthen the connection between the surrounding neighbourhoods. Kö-Bogen II demonstrates how architecture can contribute to a more resilient, people-oriented and climate-responsive city.
A Living Architectural Envelope The vegetated envelope of Kö-Bogen II was conceived as an integral component of the architecture rather than an applied environmental feature. From the earliest stages of the design process, architecture, structural engineering, landscape design and building technology were developed together to create a building envelope capable of supporting vegetation over the long term. Approximately 30,000 hornbeam plants grow within specially developed planters integrated into the inclined roof and façade surfaces. The hornbeam was selected following extensive evaluation of different species because of its resilience, ability to regenerate after pruning and long-term suitability for this unique growing environment. The plants were cultivated several years before completion in preparation for their permanent location within the building envelope. Unlike conventional green façades, the vegetation does not form an additional layer attached to the building. It is part of the architecture itself. As the plants mature, the envelope continues to evolve, changing its density, colour and spatial presence throughout the seasons. The project embraces this ongoing transformation as an essential architectural quality rather than an unpredictable consequence.
A Living Architectural Envelope The vegetated envelope of Kö-Bogen II was conceived as an integral component of the architecture rather than an applied environmental feature. From the earliest stages of the design process, architecture, structural engineering, landscape design and building technology were developed together to create a building envelope capable of supporting vegetation over the long term. Approximately 30,000 hornbeam plants grow within specially developed planters integrated into the inclined roof and façade surfaces. The hornbeam was selected following extensive evaluation of different species because of its resilience, ability to regenerate after pruning and long-term suitability for this unique growing environment. The plants were cultivated several years before completion in preparation for their permanent location within the building envelope. Unlike conventional green façades, the vegetation does not form an additional layer attached to the building. It is part of the architecture itself. As the plants mature, the envelope continues to evolve, changing its density, colour and spatial presence throughout the seasons. The project embraces this ongoing transformation as an essential architectural quality rather than an unpredictable consequence.
Water as a Resource The water management of the vegetated building envelope follows the principles of natural cycles. The inclined façade enables the use of rainwater, which is collected within the planters and forms the basis of the vegetation’s water supply. The planters are structured into a root zone filled with substrate and an underlying water reservoir. While the substrate provides a growing medium for the plants and simultaneously stores moisture, the integrated water reservoir serves as a water supply source from which the vegetation is provided with water according to its actual needs. In this way, rainwater is efficiently retained and made available for the plants. A sensor-controlled supplementary irrigation system only supports the natural process when rainfall alone is insufficient to meet the vegetation’s water requirements during extended periods of drought. It does not replace the natural water cycle but provides targeted support when required. The water supply continuously adapts to the actual needs of the vegetation, enabling a resource-efficient operation of the building envelope. A sensor-controlled irrigation system supplements this process only during extended dry periods or when natural rainfall cannot fully satisfy the plants' seasonal water demand. Rather than replacing natural processes, it supports them where necessary, ensuring the long-term health of the vegetation while using water responsibly. Water is therefore not regarded as a consumable resource but as part of a regenerative cycle. Through evapotranspiration, moisture is gradually returned to the atmosphere, contributing to the cooling of both the building envelope and the surrounding public realm while improving the local microclimate.
Water as a Resource The water management of the vegetated building envelope follows the principles of natural cycles. The inclined façade enables the use of rainwater, which is collected within the planters and forms the basis of the vegetation’s water supply. The planters are structured into a root zone filled with substrate and an underlying water reservoir. While the substrate provides a growing medium for the plants and simultaneously stores moisture, the integrated water reservoir serves as a water supply source from which the vegetation is provided with water according to its actual needs. In this way, rainwater is efficiently retained and made available for the plants. A sensor-controlled supplementary irrigation system only supports the natural process when rainfall alone is insufficient to meet the vegetation’s water requirements during extended periods of drought. It does not replace the natural water cycle but provides targeted support when required. The water supply continuously adapts to the actual needs of the vegetation, enabling a resource-efficient operation of the building envelope. A sensor-controlled irrigation system supplements this process only during extended dry periods or when natural rainfall cannot fully satisfy the plants' seasonal water demand. Rather than replacing natural processes, it supports them where necessary, ensuring the long-term health of the vegetation while using water responsibly. Water is therefore not regarded as a consumable resource but as part of a regenerative cycle. Through evapotranspiration, moisture is gradually returned to the atmosphere, contributing to the cooling of both the building envelope and the surrounding public realm while improving the local microclimate.
Climate Performance The vegetated envelope performs multiple environmental functions simultaneously. It shades the building, reduces summer heat gain, retains moisture, captures carbon dioxide, improves local air quality and creates habitats for insects and birds. The building envelope becomes an active component of the urban ecosystem rather than simply a protective skin. Its impact extends beyond the building itself. By combining shading, vegetation and evaporative cooling, the project contributes to the environmental quality of the surrounding public spaces and supports climate adaptation within the dense urban fabric. Ecological performance is therefore understood as an integral aspect of architectural design rather than an independent technical system.
Climate Performance The vegetated envelope performs multiple environmental functions simultaneously. It shades the building, reduces summer heat gain, retains moisture, captures carbon dioxide, improves local air quality and creates habitats for insects and birds. The building envelope becomes an active component of the urban ecosystem rather than simply a protective skin. Its impact extends beyond the building itself. By combining shading, vegetation and evaporative cooling, the project contributes to the environmental quality of the surrounding public spaces and supports climate adaptation within the dense urban fabric. Ecological performance is therefore understood as an integral aspect of architectural design rather than an independent technical system.
Designed to Evolve
Kö-Bogen II was designed with the understanding that architecture continues to develop long after construction has been completed. The vegetation grows, adapts and changes over time, continuously influencing both the appearance and environmental performance of the building. Long-term maintenance, monitoring and horticultural management are therefore integral parts of the project rather than operational afterthoughts. The building is conceived as a living system whose ecological performance develops over decades through the interaction of architecture, vegetation and climate.
This long-term perspective reflects ingenhoven associates’ supergreen® philosophy. Buildings are understood not as isolated objects but as evolving parts of larger environmental systems—supporting natural processes, using resources responsibly and contributing to the resilience and liveability of the city over time.
Designed to Evolve
Kö-Bogen II was designed with the understanding that architecture continues to develop long after construction has been completed. The vegetation grows, adapts and changes over time, continuously influencing both the appearance and environmental performance of the building. Long-term maintenance, monitoring and horticultural management are therefore integral parts of the project rather than operational afterthoughts. The building is conceived as a living system whose ecological performance develops over decades through the interaction of architecture, vegetation and climate.
This long-term perspective reflects ingenhoven associates’ supergreen® philosophy. Buildings are understood not as isolated objects but as evolving parts of larger environmental systems—supporting natural processes, using resources responsibly and contributing to the resilience and liveability of the city over time.