Now that (finally!) “sustainability” has become a crucial and most commonly known term in living, architecture, and design, it’s essential to know the figures that make a change with their projects.

This time, we “travel” to Germany to meet Christoph Ingenhoven, one of the leading international architects committed to sustainable architecture and founder of Ingenhoven Architekten in Düsseldorf.

With architectural studies at the Rheinisch-Westfälische Technische Hochschule Aachen and the Kunstakademie Düsseldorf, years of experience in design, Christoph Ingenhoven founded his own firm in 1985 with a focus on creating designs with an ecological core.

According to international standards, his projects achieve the highest certifications, including LEED, Swiss Minergy Standard, BREEAM, and DGNBhave, and have been awarded several prizes and international distinctions. Every design is of unique aesthetics; the Lufthansa HQ at Frankfurt Airport, the European Investment Bank in Luxembourg, the HQ of the Daniel Swarovski Corporation at Lake Zurich, the Kö-Bogen II, to name just a few.

Christoph Ingenhoven has been a juror in many international competitions and awards; he has given lectures worldwide, while he is also a member of the Architektenkammer Nordrhein-Westfalen, the BDA (Bund Deutscher Architekten), and RIBA (Royal Institute of British Architects). 

I was eager to learn more about his works, his thoughts on the future of design and architecture after the pandemic, and, of course, the term he gave birth to, “supergreen® concept.”

“Supergreen® means much more to us than urban greenery. Humanity is currently undergoing the largest population shift in its history – moving from the countryside to the cities. With that and the growing population, the only alternative is larger, denser cities. We need to equip our cities so they can accommodate even more people. We need cities that are both dense and mixed.”

Elizabeth Soufli: You are committed to sustainable architecture; your projects have received the highest certifications according to international standards. You have even created a new term, the “supergreen® concept” pointing that every part of a project should be green. What’s the philosophy behind it?

Christoph Ingenhoven: Our supergreen® concept sums up our approach at ingenhoven architects – a holistic system of insights and principles that is constantly evolving. 

More than 20 years ago, we used concepts such as self-sufficiency – the idea that everything you need is produced on your own property – to help articulate our priorities. Today, supergreen® represents a comprehensive philosophy, bringing together a whole range of parameters that we apply to our projects. This includes, among others, climate-neutral construction. 

Another important parameter is replacement, meaning that our buildings give back to the Earth what we took away through their construction in terms of biocapacity. 

It’s also important for us to be extracurricular, meaning always asking what a building can do for the community. What added value can it contribute voluntarily, which was not required from the outset? Wherever possible, we try to create new public spaces that are free of pressures to consume. Given the world’s growing population, our cities have to become denser. But that also threatens to reduce public space. 

We look at how our buildings can contribute to resilience. How can the consequences of global warming, such as heavy rainfall or hot summers, be absorbed, for example through smart shading systems or green facades and roofs? Urban greenery plays a major role in nearly all of our projects – as an integral aspect of the building that is part of the concept from the outset. 

E.S: What are, in your opinion, the qualities of a GREEN GOOD DESIGN?

C.I: To begin with, there’s the question of necessity. In general, it’s about building in harmony with the world’s resources. We consume too much, and we know it. Specifically, we consume 170 percent of the Earth’s resources – our ecological footprint exceeds the Earth’s biocapacity by 1.7 times. Here in Germany, with our high standard of living, we currently need 2.7 times as much as our planet. The construction industry accounts for about 60 percent of global resource consumption. At the same time, the world’s population is growing. We need to radically rethink our approach, for instance, by focusing on zero-emissions buildings using fewer construction materials.

E.S: Throughout your career, you’ve designed dozens of projects, from public buildings to the headquarters of mighty companies such as Google, Lufthansa, Swarovski… Is there something that you didn’t have the chance to design yet and you’d love to?

C.I: There are a lot of projects that I would like to realize. A large clinic, an airport, personally, I’d love to build a church. As an individual, I am still searching for answers to big questions, and churches are places where people seek answers. Building a bridge is something else that I’d like to do.

E.S: When did you decide to go green in architecture?

C.I: Sustainable building is something I’ve thought about from the very beginning as a way to make a difference in the world as an architect. 

There’s an image that deeply moved me as a youth and still does today: “Earthrise,” the first photo of the Earth from outer space, showing it as a blue and white sphere in the dark expanse of the universe. It was taken on December 24, 1968, as the Apollo 8 orbited the moon. That powerful image shows both the beauty and vulnerability of Earth and changed how people, myself included, think about our planet. 

The late 1970s, at the beginning of my studies, was the heyday of postmodern architecture. Everything – except for sustainable building – was important. For us students, that was interesting for a while, but then it repelled us. We felt it was time for something entirely different, ultra-modern, and ecological at the same time. When I got my degree in 1983, the Greens were gaining representation in state parliaments for the first time. There was the energy crisis and mass demonstrations for peace and the environment. It was normal for us to think about sustainability. We drew inspiration from pioneers like Heinrich Böll, Joseph Beuys, Petra Kelly, and Al Gore.

E.S: Tell us more about “Marina One” in Singapore’s subtropical climate. From the elegant forms to the city’s views and its “Green Heart” of natural vegetation, this is an impressive green building! 

C.I: With Marina One, our aim was to create a role model for building in tropical megacities – not a traditional “fully air-conditioned box,” but a specific response. 

In Singapore, the Urban Redevelopment Authority (URA), which also allocates property – for 99 years, you can lease the land, not buy it – mandated a 100% Landscape Replacement Area policy. For every square metre of land that is built on, one square metre of greenery must be created within the site. Additionally, at least 25 percent of the built footprint must be public space; it must be covered due to the heavy monsoons. These requirements also apply to Marina One. With the terraced, undulating landscape of the publicly accessible “Green Heart,” we give as much as 170 percent greenery back to the city. The jungle-like atmosphere – with a total of 350 tropical plant species – begins in the central green area on the ground floor and continues upwards through the first four floors, interspersed by pools of water and pathways. These are followed by the Sky Gardens on the 4th and 15th floors and the roof.

Horizontally projecting louvres, 1.2 to 2 metres deep, envelop the entire complex. On the inside, they underscore the fluidity of the organic shape. They aren’t just a design element but also provide valuable shade from Singapore’s intense overhead sunlight while allowing an unobstructed view of the outdoors. Based on wind movement simulations, the shape of the Green Heart was designed to optimize the air circulation, which is amplified by the Sky Gardens – so there’s always a fresh breeze blowing through the building. The result is an outdoor space where people enjoy spending time, without the need for large fans.

E.S: “Going green” in architecture is one thing, but how do you get people to go eco through architecture? How do you adapt such designs in cities like London, Paris, Frankfurt?

C.I: As I explained earlier with a few of the parameters that guide our work, supergreen® means much more to us than urban greenery. 

Humanity is currently undergoing the largest population shift in its history – moving from the countryside to the cities. With that and the growing population, the only alternative is larger, denser cities. Covid-19 won’t change that. So we need to equip our cities so they can accommodate even more people. We need cities that are both dense and mixed. A metropolis like Houston, Texas, consumes many times the resources and energy of much larger cities like Singapore. 

Part of the answer lies in making our cities bicycle-friendly and pedestrian-friendly as soon as possible. And naturally, we also need a lot more green space in the city. 

E.S: Europe’s Biggest Green Facade… You made it happen with the “Kö-Bogen II” commercial and office building in Düsseldorf, an extraordinary green structure, an urban response to climate change. Tell us more about its supergreen® concept…

C.I: The green facade system at Kö-Bogen II contributes in many ways to improving the microclimate of the city, supporting biodiversity and fostering people’s general wellbeing. The hedges bind carbon dioxide and dust, and absorb noise. One key aspect is that they reduce the urban heat island effect, as the expansive green facade acts as a largescale energy converter. Especially in summer, conventional mineral or bituminous surfaces heat up considerably, store part of the heat absorbed, and release it over a longer period of time. This causes our inner cities to warm up more and more. But layers of foliage are always somewhat cooler than, or as warm as, the air temperature.

Another important effect of the green facade system, particularly the roof, is rainwater retention. Even during heavy rainfall, rainwater is collected and stored. Only excess amounts, which the plants and containers can no longer hold, then drain off. In many urban areas, the water cycle is interrupted by sealed surfaces, but Kö-Bogen II closes the gap in the water cycle. It’s a natural way of preventing an overload of the urban sewerage system.

To ensure that the hornbeam hedges thrive over the long term as an integral part of the building, we developed a comprehensive concept for the construction, care, and maintenance of the planting system in close cooperation with the phytotechnologist Prof. Dr. Strauch from Beuth University of Applied Sciences in Berlin. As part of the urban development agreement, the investor was obliged to assume responsibility for the green facade for 99 years.

E.S: What are the biggest challenges that a green project has to overcome to achieve the lowest carbon footprint possible?

C.I: Everyone involved in the building process needs to contribute to the effort. Also, meeting the maximum applicable criteria of the certification system in the country – LEED, DGNB, BREEAM, etc. – should be the norm and, if possible, they should be exceeded. Currently, these conditions are still the exception. Only public pressure will help; building the wrong type of structure needs to become socially unacceptable.

E.S: Lastly, what makes a project successful? Is it people’s appreciation and desire to spend time in it, or the architect’s satisfaction with the outcome?

C.I: The greatest reward for me is when a building has been truly accepted, when it becomes a living, integral part of its respective environment. Being able to look back a few years later and say, “it was good that we did it that way” – that’s what fills me with pride.