Bau 2021 Takeaways

We don’t have time to change

“We need to build differently now.” (Nils Nolting from Cityförster) 

The future of construction was a big topic at the Bau2021, which was held online this year.

A Forum on that specific topic was organized in cooperation with Bauwelt, DBZ, and BundesBauBlatt for which various architects came together and presented their ideas of what the future of construction could look like and what aspects we need to take into consideration in our planning process. Next to the Forum companies presented changes in their products, changes in norms or regulations, and projects they planned that inspire. We received a lot of food for thought and have summarized the take-aways from the presentations we heard and the discussions we had.



The construction industry is the biggest in the world. It makes up 13% of the global GDP and is responsible for 40%-60% of global greenhouse emissions. (Arup, 2020) 

Buying new raw materials is still cheaper than reusing old ones. This calls for a dramatic change and for that to happen we need certain policies in place. In December 2019 the European Commission agreed to Ursula von der Leyen’s Green Deal. The goal of this deal is to bring greenhouse gas emissions to net-zero by 2050. The Green Deal promotes circular economy thinking, extended producer responsibility, and waste reduction. The plan is to include legal requirements to boost the market of secondary raw material and mandate recycled material. Both public and private buildings will have to be renovated to reduce emissions. “97% of our existing building stock requiring major upgrades to meet 2050 decarbonization targets”. (Arup, 2020) This is a step in the right direction. Through the implementation of the circular economy, 70% of C02 gases can be reduced. (Antonino Vultaggio) 


Cradle to Cradle

“Instead of being less negative, let’s try being positive.” (Antonino Vultaggio) 

The Cradle to Cradle (C2C) design principle was created by the chemist Michael Braungart and the architect William McDonough. It describes the safe and potentially infinite circulation of materials and nutrients in cycles. Companies often intent to reduce their ecological footprints, aiming for a “zero-emission” or “free-from” strategy. The goal should not be less bad but positive. Dr. Peter Mösle from EPEA explains that to successfully plan according to C2C and construct eco-effective buildings, 4 steps are necessary. The first step is the mindset of the project team members. The members of the project team must have the common goal of creating something eco-effective, prioritizing and investing time into it. The second step is a method for circular building, such as using buildings as a raw material depot. The third step necessary is competence. Dr. Mösle introduces the circular engineer as a position in a planning team. The last step needed is a process. We as planning teams need to reorganize our priorities and take the environment and a building’s footprint into serious consideration when planning. 


Building materials

We need to rethink the materials used in the construction industry. Often members of the planning team are not aware of the impact materials have or the better alternatives out there. The DGNB is trying to create transparency in that area using their construction material bank. Unfortunately, as mentioned above it is still cheaper to buy new raw material rather than reuse secondary material. However, if we give Materials an identity, they can no longer anonymously vanish to waste. That is what the company MADASTER made its mission. “Each building becomes a depot of materials with a certain value.” (MADASTER, 2020) The materials in that case will ideally be unmixed, toxin-free, and detachable. MADASTER created a transparency platform about material assets in the built environment. Dr. Mösle explains that if we can monetize these material banks and we can include them on the company balance sheets it will become cheaper to build per cradle to cradle. The true cost of material, beyond its monetary value, will be taking into consideration. 



Friedrich Ludewig from ACME in London explains how thanks to Digitalization and technology „Communicating space is easy” now. Architects have had to translate three-dimensional space into two-dimensional data and plans with sections and elevations. Now using technologies such as BIM a three-dimensional model will be created that helps the customer understand the architect’s vision pre-construction and leads to better communication and collaboration between the planning members. This opens new possibilities for complex forms, coordinating design, and for the way we talk about space. 

Tobias Wallisser and Alexander Rieck from LAVA, who are the architects of the German pavilion at the World Expo 2020+1 explained that a BIM model is needed to submit a design for the EXPO 2020. Mirco Amstad, the project manager of the German pavilion explains: “The one main thing about the pavilion is the structure itself, which we are building out of steel, with concrete slabs, and cores. Hence, we are using BIM to make the process easier.” (Construction Week, 2020) This year’s pavilion will be made with 750 tons of steel. Markus Lager from Kaden+Lager explains that BIM is just the beginning and artificial intelligence (AI) will extend the fundamental idea of BIM and present us with new possibilities. AI will take over certain jobs of the architect, which Lager sees as a positive development, leaving him with more space for vision and creativity. Wolf Lotter goes even further by saying: “It’s not too much artificial intelligence that threatens us, but too little natural intelligence”.


CO2 storage

One possible solution to help meet the Green Deal targets of bringing greenhouse gas emissions to net-zero by 2050, is timber. Markus Lager from Kaden+Lager presented his ideas under the motto „Timber construction, soon to be normal”. The most beneficial aspect of timber construction in regards to the environment is that it stores CO2. The CO2 stored in the wood is removed from the market and has then no harmful effect on the atmosphere. In an interview with Bauwelt Lager says: “Our high-rise building in Heilbronn contains around 1,500 cubic meters of wood, which binds roughly as much CO2 as 500 cars emit in a year.” He goes on to explain that to store as much CO2 as possible, one needs to build the ceilings from solid wood since that is where the greatest mass in the house is. As of today, 18% of completed buildings in Germany are made of wood. This number is rising. Markus Lager is trying to encourage designers to use more timber. New things often take more time and effort but as construction with timber becomes more established, it also becomes easier and less time-intensive since solutions to technical problems have already been found. Lager believes that timber will define our future and it is no rocket science. His opinion is supported by Ursula von der Leyen’s statement: „Our building caused 40 percent of our emissions. They need to become less wasteful, less expensive, and more sustainable. And we know that the building sector can even transform from a carbon source to a carbon sink by using organic building materials like wood and smart technologies like AI. But this is not just an environmental or economic project. It has to be a new cultural project for Europe.”


Low-Cost Housing

It is estimated that 150 million people are currently homeless while 1.6 billion people lack adequate housing. (Chamie, 2017) The Bau2021 talked a lot about sustainability and the future of housing and construction to minimize the ecological footprint the industry currently has. Very few however talked about the growing housing crisis we are in and about possible solutions that are desperately needed. One of the few that did present a solution was Mohammed Daei from BT Innovation. They developed the Butterfly Battery production technology that allows them to produce precast concrete elements faster and simpler. The technology leads to high productivity with a relatively small base area that is almost location independent. The surfaces of the concrete elements are five-sided formwork smooth and no further finishing is necessary. No technical know-how is required to use this equipment, which is a huge benefit as it can create local employment that is often present in areas with large numbers of homelessness. The standard concrete house that will be produced using the butterfly battery production system has a base area of 36m2. It has four rooms including a bathroom with a shower and toilet. The house will come with outlets, light switches, and a water connection in the bathroom and kitchen. There is room for 4-8 people. A house like this can be assembled in 2 hours and cost around 6,000 Euros. 


Be a visionary

The way we are used to building is not sustainable. While we have already started to change in the right direction, it is now time to start thinking in completely new ways. 

Windy Maas, the cofounder of MVRDV, leads The why factory an independent think tank and research institute that envisions the city of the future. He describes a vision as a dream for the city that offers a long-term, cohesive, seductive, and powerful perspective for future societies. In 2018 around 55% of the world’s population was living in an urban area or city. (Meredith, 2018) According to the UN, this number is rising to 68% over the coming decades. With a growing population and an incising strain on the environment, we need to rethink the city of the future without the loss of individuality. Society is changing rapidly and the year 2020 has made a few things very clear that will influence the way we live in the future. We no longer need to live in a city for work. Working from home has become the new norm due to Covid19 and some companies have decided to get rid of offices as we know them. The need to work in a city and the desire to live in a house with a garden that brought people to the suburbs might just have changed. Covid19 also highlighted the huge impact Globalization has. Pre-Covid19 People traveled further and more often than ever before. This leads to people from different backgrounds and different places of the world with different housing cultures coming to the world’s metropoles and living together. Collectivism becomes more colorful and both private and shared space changes. People singing together from their balconies when stuck in quarantine has demonstrated how important shared space is. A disadvantage of globalization is that the way we consume here leads to problems elsewhere and a single solution to a single problem will not suffice. We need an integrated approach that adds value in many areas to prevent a single solution to cause another problem. 2020 has been a difficult year but it highlighted many exciting changes in our society that can now feed our visions for the future. „We need to take optimism and reclaim the future of our cities.” (Windy Maas)



Arnold, W. How can you reduce your carbon emissions?. Retrieved 20 January 2021, from


Chamie, J. (2017). As Cities Grow, So Do the Numbers of Homeless | YaleGlobal Online. Retrieved 20 January 2021, from


Friedrich, J. (2020). BAUWELT – Holzbau an sich ist kein Argument mehr für Qualität. Retrieved 20 January 2021, from


Meredith, S. (2018). Two-thirds of the global population will live in cities by 2050, UN says. Retrieved 20 January 2021, from


Smith, B., Kirk, P., & Doody, L. (2021). The EU Green Deal and building retrofits: making it work for everyone. Retrieved 20 January 2021, from


Warrier, R. (2021). Expo 2020 Dubai’s Campus Germany is a “big” but “good challenge”. Retrieved 18 January 2021, from


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