How to make sustainable buildings for all? A talk with Christophe Levy

The Norman Foster Foundation and Holcim, a global leader in sustainable building solutions, have joined forces with a strong belief: that everyone has the right to a home, and everyone should have access to sustainable building. 
Their collaboration resulted in the Essential Homes Research Project, a pioneering model for sustainable and dignified housing for displaced people. This project was inaugurated in Venice at the occasion of 2023 Biennale of Architecture launch.
Norman Foster Foundation designed the housing concept to meet essential human needs, providing safety, comfort and wellbeing for people in displacement, who can live in temporary settlements fordecades. Holcim brought the project to life with a range of its sustainable building solutions, making it low-carbon, energy-efficient and circular.

We had a brilliant chat with Christophe Levy, scientific Director and Director R&D Concrete & Aggregates at the Holcim Innovation Center who oversaw the development of the entire project.

What does innovation mean to you and what’s your idea of the future? 

Innovation is my whole life. I’ve dedicated my entire life to relentlessly pursuing new ideas.  
My definition of innovation is the invention which is going to be developed and sold in the market. An invention which is not sold, for me, is not an innovation.
My vision of the future is bright. I have three children, and I hope they will be even happier in life than I am. My idea regarding the future is positive, even I know that we are facing a lot of issues. One of the main issue is clearly the climate change. My idea of the future, professionally, is clearly to do what I can in order to limit this CO2 reduction to zero, let’s say, in 2050.  
In this regard, people like us, players in the cement industry, must commit themselves to achieve net-zero emissions and make significant reductions in CO2 emissions. It’s a matter of death or life. Here at the Holcim Innovation Center, 85 percent of the research conducted by our 210 researchers is dedicated to CO2 reduction. We are working on the clinker level. Clinker is an artificial stone produced using limestone and clay, and it is the main component in cement production. Then you mix cement with some coarse aggregates on water and you’ve got concrete.We need to work also on the reduction in the concrete, then the reduction in building systems, and then building. Another important point is the circular economy: we need to limit and maybe one day not use natural resources anymore. 
For example, in one of my recent innovations, I came up with the idea to demonstrate that we can create concrete made from 100% recycled materials, without the need for any natural resources. We are currently constructing a building near Paris. It is made entirely from recycled materials, including recycled sand, coarse aggregate, water, and cement. 
We haven’t used any limestone or clay but have relied solely on industrial by-products from nearby plants. I believe it’s crucial for us to demonstrate, not only with this building but in our future development, that concrete is just as recyclable as steel, aluminum, or any other material. 

Your involvement in the Essential Homes Research Project, inspired by the Shelters Workshop, demonstrates a commitment to addressing challenges like human recovery after natural disasters. What were some key takeaways from this project, and how do you envision its impact on the future of architecture and housing solutions?  

My main takeaway is that I had a lot of fun. It was truly amazing to work with Norman Foster himself, as well as with his Norman Foster Foundation in Madrid, on a project that gave meaning and purpose to my daily work. It was incredibly exciting.
I met a lot of people, especially because Norman Foster and our team organized a shelter workshop in June 2022.
I was one of the experts, but the others were primarily focused on refugee camps. We had people from the Global Justice Center in California and even the director of the largest refugee camp in Syria. Additionally, we had individuals from the European Union and the UNHCR, the refugee commission. We collaborated with ten top architecture students to explore ways to improve existing structures. Based on the work we accomplished, Norman Foster and I decided to move forward with designing this beautiful, essential home and make it a reality.

Another important point, in my opinion, is the notion that something may seem impossible but isn’t.  I was keen to see a tangible product, something concrete.  
To be honest, when I first delved into this field, I quickly learned in June 2022 that using permanent materials was not allowed.
In fact, it’s worth noting that Uganda is the only country that permits refugees to stay where they are. This is another key takeaway. Unfortunately, most other countries refuse to let them stay, which is quite frustrating. It’s ironic because one of the experts, John Hoare, a professor from Cambridge, conducted a study on the duration refugees spend in so-called temporary shelters, and the worldwide average is 28 years. With two populations, one around five and the other one around 40 years. 
That’s another takeaway: temporary is not that temporary.  
It was very difficult to convince people that we can use cementitious materials. When you look at the social home, I’m very proud to have been able to push for it and convince people to use it.

Another significant point to consider is that the initial objective was to create this for refugees. However, the end result is undeniably stunning. Personally, I find it quite magical and truly a work of art. It’s a bit expensive compared with the existing, obviously, United Nations tents but you cannot compare it because we are giving intimacy, comfort and dignity.  

We plan to go in Morocco, particularly in the village of Turzo, which was completely devastated by an earthquake, and to use the same technology, rollable concrete, to shape it into a structure resembling a barracks. Afterward, we’ll add water, and it will become incredibly sturdy with exceptional strength. We anticipate being able to complete it in just one day.
We’ll start by building one or two units and then explore the possibility of scaling it up by a factor of 10 or even 100. I’m immensely proud that this innovation will be beneficial for the impoverished and displaced people in need. 

The key takeaway here is that just because you may not achieve all of your targets, especially economic ones, doesn’t mean you should give up.  

It’s a great opportunity to draw inspiration from the project itself and leverage the other aspects that have been successful while working on the areas that still need improvement.
I believe the future of architecture will witness a renaissance of the elegant catenary shape. The catenary shape is remarkable for its load-bearing capabilities due to its inherent purity and robustness. What Norman Foster’s architectural insights offer is a unique perspective on how this catenary can be harnessed. My hope is that the impact of this architectural innovation could lead to the revival of arch-based designs rooted in the catenary shape. As for the impact of Essential Homes on housing solutions, I must admit that I’m collaborating with developers in France, as well as in other countries like Costa Rica and Spain. The aim is to either replicate or adapt what we’ve achieved with social shelters and explore how we can multiply and expand this concept. Perhaps not exclusively for temporary purposes, but with some adjustments, transforming it into a sustainable permanent habitat. In essence, the goal is to scale this solution 

How do you see the role of 3D printing technologies in addressing humanitarian challenges, such as providing emergency shelters?  

In this case, I believe the approach we’ve taken, based on this particular shape, is much simpler and faster than using 3D printing.  
I’m a big fan of 3D printing; in fact, when I returned from the USA, I was quite enthusiastic about it, especially when it came to concrete printing.  
It’s a fascinating technology. I serve as a scientific director working with numerous universities, and practically every university I’m acquainted with is engaged in 3D printing. It’s appealing to students because it’s not only beautiful but also enjoyable. It combines various technologies and knowledge from different domains. It’s truly remarkable. 

What I’m learning from Morocco, a direct takeaway from a social home, is that in fact, in the humanitarian support or humanitarian construction, there are three distinct phases.

  1. The first phase: is the immediate one, where the priority is to provide families with something affordable, easy to transport, and quickly constructable. Unfortunately, in many cases, this has meant using tents. I say “unfortunately” because in some refugee camps, people end up living in tents for extended periods, which doesn’t make sense. My concept was an attempt to replace tents, but it involves more substantial materials. We can’t follow the same approach. Perhaps one day we’ll have containers with everything ready, but that’s not an immediate solution. It’s something we might consider in the coming weeks rather than the next day.  
  2. The second phase. We must create something that offers more comfort, a temporary solution that can last for perhaps six months or even a year, to allow for the rebuilding of infrastructure and more.  
  3. The third phase, which is permanent, truly permanent. 

3D printing is a fantastic technology and can be well-suited for these needs, particularly for the first and second phases. However, for the third step, the permanent one, it may not be quick enough.  
What’s wonderful about 3D printing is that it allows the same equipment to be used to create diverse and affordable housing options. This flexibility can be a significant asset, especially in refugee camps or communities, helping us avoid the common practice of mass-producing identical, uninteresting houses. 3D printing offers the opportunity to break away from this, and the approach you choose ultimately depends on your design goals. 

I make a parallel with the telephone. We have been successful in Kenya, in Malawi, let’s say, in South Africa, and we are going to develop it in other countries. I used to live in India, and there, very few people had regular landline telephones. They went straight to mobile phones. I think in some countries, we can see this quick evolution or jumping evolution from hurt or from poor, vernacular housing to 3D printing without going through the traditional way of printing in Europe. 

The School of Disruption aims to democratize access to innovation and STEM knowledge, especially for individuals in developing countries providing deep impact scolarship. How do you believe initiatives like this can contribute to a more equitable distribution of innovation capabilities worldwide? And what’s Holcim is doing to facing this gap? 

Initiatives like these are essential. When I reflect on my career, back when I worked for Lafarge, which later became LafargeHolcim, about 35 years ago, it was primarily a French company with a few small sustainability initiatives abroad. But even 15 years ago, the focus shifted significantly towards Asia and Africa. Today, our main areas of focus are the Middle East, Southeast Asia, South America, and Latin America. We, as a company, cannot thrive without continuous innovation.  

We prioritize value over volumes, and innovation is imperative, especially in the developing countries where our major markets are located.  

We don’t have a choice. Restricting our innovations only to France and Switzerland wouldn’t make any sense in terms of return on investment; it would be impractical. I aspire for a more equitable world and a fairer distribution of innovation capabilities. Nevertheless, regardless of our desires, we must act. It’s not just a moral obligation; it’s a practical necessity. We’re actively pursuing these initiatives. In fact, it’s interesting because just yesterday, I had a discussion with a team in Morocco about the third step: How can we provide a solution to rebuild the villages that were devastated by the recent earthquake? The best solution is based on Durabric.  

Durabric is a solution that we developed in Malawi approximately 15 years ago. It involves a special cement mixed with the clay found underfoot. You combine a small quantity of cement with this clay, press it, and create bricks, which eliminates the need for traditional fired bricks, thereby addressing deforestation concerns. This solution was a specific request from the government of Malawi. Durabric was developed in Africa, particularly in sub-Saharan Africa. Today, we are planning to use this system, and it’s proving to be remarkable. 

This approach is not suitable for France, Switzerland, or Italy, but it’s extremely effective in more developing countries. It’s an example of innovation that isn’t only developed in Europe and then transferred, multiplied, and scaled in other countries. What I mean is that these innovations are conceived in and evolved from the countries that face these unique challenges, and then they spread to other nations, like Bangladesh, for instance. It’s a no-brainer for me. We have to do it. I believe our team is quite adept at addressing this gap. We must do this because it aligns with our global strategy and business goals.  

We aim to develop and sell innovative and sustainable solutions, and it’s not just for Western Europe and the US; it can be applied worldwide. 

What factors do you believe will drive the comprehensive adoption of 3D printing technology? How can we lower the key barriers or limitations to the adoption of 3D printing in building construction?  

For me, the primary concern is the CO2 footprint. I mentioned that it’s a top priority for us. When I examine our accomplishments over the past 10 years, our ongoing developments, and especially what our competitors are striving to achieve, we are currently focused on cement-rich mix designs. I won’t delve into the technical details, but in most cases, we’re using a form of concrete without coarse aggregates, which means we end up using more cement. Typically, this involves high CO2 emissions due to the use of premium cement. We are actively engaged in efforts to significantly reduce the CO2 footprint of what we refer to as “pink concrete,” which is the concrete or mortar we use in our 3D printing projects. 

Another aspect is making solutions more cost-effective on a global scale. This involves more affordable equipment and inks, and we’re actively working on these aspects. Then, the challenge is to demonstrate that these innovations work effectively on a large scale. These hurdles have not been entirely overcome yet, but I hope they will be addressed soon. 
I understand that I work in a highly conservative industry. Construction is known for its conservatism, and convincing people to embrace 21st-century technology isn’t easy. I won’t name names, but compared to other fields, the stakes are higher in building design because you’re ensuring the safety of people who will reside in these structures. Therefore, there is little room for taking risks. Advocating for new technology can be a challenging endeavor. I’m well aware of this since I’ve had the privilege of patenting around 80 patents in many different countries. But the path from patenting to practical implementation is not always straightforward. It’s simple to conceive an idea and secure a patent. However, the real challenge lies in convincing, especially those who will bear the risk if something goes wrong and it’s their responsibility. This is why I’m considering involving engineering consultants. I’m not pointing fingers at them; it’s just a reality. We have to demonstrate that it’s both cost-effective, environmentally responsible, and easily scalable. I have a strong sense of optimism about this, but it will require some time. 

What guidance would you offer to construction companies facing challenges in embracing innovation, and why do you believe it’s crucial for them to prioritize innovation in today’s construction landscape?  

First and foremost, we are considering our customers, the construction companies. I have no intention of dictating what they should do. I respect them, and I won’t impose anything on them. When you examine industrial history and the history of construction companies, it’s evident that those who haven’t embraced innovation are no longer in the picture. We need to set ourselves apart.   

The most successful construction companies are often those that have embraced innovation. In the long run, it’s quite clear: innovation is a path to greater success, increased profitability, the ability to attract top talent, and it creates a virtuous cycle.

But I mustn’t forget that, as I mentioned earlier, the construction field is known for its conservatism. There are, I believe, two strategies to overcome this conservative nature:  

  • The first one, which is more popular today, especially for the larger contractors, is when these construction companies not only handle the contracting but also the design. It’s much more effective because they can take risks from the outset. When they have the complete picture, it becomes easier to innovate. This is one key aspect.  
  • The second approach involves taking financial risks.  

We’ve secured funding from various countries, including support from Europe, which is a significant opportunity today. I believe that innovation is thriving, thanks to the support from Europe. In fact, I had a meeting yesterday with the European Innovation Council. In any case, we have substantial funding, which makes it an ideal time to take calculated risks, especially because there’s financial backing available for insurance and such. Taking risks, whether with funding or through partnerships, often involves collaboration with numerous partners at various levels, including contracting and design, among other aspects. I believe this is an excellent opportunity. Some construction companies are taking full advantage of this opportunity, demonstrating remarkable organization and a willingness to take construction risks. On the other hand, I’ve observed other companies that are more cautious. In my view, concerning construction companies, innovation is a matter of long-term survival.  

Both your organization and the School of Disruption have explored innovative approaches to solving complex problems in architecture and construction. What are your thoughts on the importance of converging technologies and knowledge from different fields to drive innovation in the construction industry?  

I’ve always been inclined to borrow ideas, a practice I’ve followed for 35 years. I enjoy drawing inspiration from other industries and even the natural world. It could be in terms of how we organize our R&D efforts, or it could be in terms of our research focus. I’ve found that embracing a variety of technologies is often essential if you genuinely wish to set yourself apart and foster innovation. Exploring different fields is a necessity in my view. 
For instance, when I consider our team of 210 to 220 researchers, we have experts, engineers, and technicians in areas like inorganic chemistry, organic chemistry, the intersections between these two, physical chemistry, rheology (the science of fluid behavior and movement), microstructure, digital technology, robotics, and even structural engineering. We also have experts in fundamental physics, covering acoustics, thermal insulation, and more. Our team comes from various backgrounds and possesses diverse expertise, which is why I believe we’ve achieved considerable success in terms of innovation. 
It’s not only enriching but also enjoyable because, personally, I know that every day I enter the lab, I’ll learn something new. And that’s truly fantastic. It’s undeniably essential if you aim to excel in innovation. Over the past four years, we’ve hired more than 70 researchers and technicians, which is quite substantial. While some people have moved on, we’ve welcomed numerous new talents. Over the last two years, many of them have arrived from diverse domains, bringing knowledge we didn’t possess previously. This applies to processes, aggregates, biology, and more. We’re even recruiting fresh faces with expertise in data science, artificial intelligence, and how to scout startups. These are roles we wouldn’t have considered hiring for ten or twenty years ago, without a doubt. 

To know more about The Essential Homes Research Project by Holcim & Norman Foster:

This interview is part of our dossier on Sustainable Building. Other content:

Take a look at our Space Architecture & Design Workshop 2023:

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