Building for the future: Interview with Professor of Architecture and Resources

Which sustainable building materials will be used in the future?

From a sustainability perspective, various debates are currently being held that go in different directions: Some ask how we can ensure that materials that are durable are used more. Longevity is an important criterion here. The other side of this debate focuses on how we can move away from highly energy-intensive materials and towards materials with a low primary energy content. These are often materials based on renewable raw materials, such as wood or natural building materials. Wood has another advantage. This building material is one of the materials that have a CO2-reducing effect. These are materials that store carbon dioxide (CO2) during extraction and do not release it. In contrast, a lot of CO2 is released when traditional building materials such as aluminum, steel or even concrete are produced.

Wood as a building material therefore has the potential to bind a lot of CO2. This also applies to varying degrees to all other renewable building materials. That is why there is currently so much focus on this area, because it offers an opportunity to actively counteract climate change and store CO2.

The question of the choice of building materials is central to the so-called “building turnaround”. In this context, renewable materials in particular play an important role. In addition, the topic of recycling, of so-called circular construction, is becoming significantly more important. From this point of view, traditional building materials such as metals are also experiencing a kind of “revival”. For circularity, steel or even aluminum are potentially very suitable materials, even though they are energy-intensive.

However, circularity also requires new ways of constructing. Today, we are called upon to design buildings in such a way that we anticipate their subsequent dismantling during the construction phase. The recyclability of building materials must therefore be taken into account. A lot of research is currently being done in this area. Our understanding of materials and construction in the building sector will change substantially as a result. The topics of sustainability, circularity and CO2 binding are increasingly being considered in context.
 

Which energy sources will prevail?

This question is certainly extensive and complex. Many different solutions are needed, a mix of energy sources. On the one hand, there is a demand for biomass-based energy sources, such as biogas and wood. Added to this is the idea that thermal utilization is a building block in a value chain of renewable raw materials that should be as long as possible. Combustion-based biomass utilization can be an answer in the direction of renewable energies, especially in existing buildings, particularly when the building can only be made energy-efficient to a limited extent.

In addition, electricity is becoming increasingly important as an energy source, having been somewhat neglected in favor of nuclear power and coal for a long time, due to the development of photovoltaics and wind power. Electricity is increasingly becoming a renewable energy source because wind and PV systems can be integrated very well. In addition, there is hydrogen as an energy source that still needs to be developed. Some countries are also banking on a revival of nuclear power. In Germany, this is hardly an issue at the moment.

It is also apparent that there is a shift from centralized, large-scale technologies to decentralized, networked, multimodal solutions. We see a competition of systems: some rely on electricity, others on hydrogen, still others on nuclear power and yet others on biomass. I would always ask the question: what is the appropriate energy source for the project and in the specific situation?

How can extreme weather conditions be counteracted by sustainable construction methods?

We have to look at this in a more complex way. What, for example, causes climate extremes? Where is the construction industry itself to blame? Where can it make a contribution?

To a large extent, the construction industry itself is a “problem producer”, since construction is usually very resource-intensive. In many places, planning is not yet being done wisely enough. For example, construction is still taking place in flood areas. But if we think about the fact that we have to adapt our buildings to the conditions, then there are ideas for doing so, for example, building typologies that are detached from the ground, elevated or perhaps even able to float.

This means that our building practices will change. The debate focuses on the principles of sufficiency, efficiency and resilience. I think the topic of robustness, which is currently being discussed more and more, is relevant. But this is not an immediate response to the intensifying weather conditions. However, we are seeing a turnaround. Our understanding of where and how we build and how we operate our buildings is changing. But the answer is complex and diverse and probably not always clear. There should be a competition of the best ideas. Perhaps diversity is a good strategy at this point to find many answers to a complex challenge.
 

What does the future of living and working look like? Will there be fewer office buildings and more mixed-use buildings?

In any case, there will be more and more hybrid buildings. These can be used as office buildings, but a conversion to residential or educational use is also conceivable. There are also many offices in former apartments and there are good apartments in former office buildings. It's about robustness, that buildings can be used for many things and that they are no longer thought of as specifically and functionally one-dimensional. For example, I am overseeing a project in which a former furniture store is being converted into a school. In many cases, the change of use holds great potential for new and ever-changing uses.
 

What potential do you see in older buildings?

The potential of old buildings is that they carry a history within them. This is an interesting and important phenomenon. “Continuing to build” and “rebuilding” differs significantly from “building anew”. At best, new buildings bring “the new” into the world and reflect new needs and new ideas about space. However, we have a great deal of existing buildings and it can be much wiser to continue to use them and to think about how what we have can continue to be used. But sometimes it is necessary or sensible to remove buildings, for example, when static systems fail or pollutants have been used that cannot be traced.

On the other hand, new construction relies on the potential for “newness”. If we build structures that are not radically better than what we already have, we should turn away from new construction and turn to the existing building stock, enriching and improving it.

How and from whom can companies get comprehensive advice on how to focus even more on renewable energies in the future when modernizing their buildings or having new ones built?

I recommend that owners and operators – especially of larger building complexes – have partners at their side to support them in construction, renovation and maintenance. These should be experts in space, resources and energy – ideally a team that thinks in terms of use, space and resources in a conceptual, long-term and multidimensional way. Furthermore, when new ways of thinking and approaching issues are required, student research projects or targeted research or development contracts with universities can be an effective means of achieving this. At Alanus University, we cultivate collaborations with a wide range of partners. If companies are looking for fresh ideas and new ways of thinking about space, use and resources, for example, how to deal with a rather unloved building stock, universities, but also professional partners, can provide an important and potentially wertvollen Innovationsbeitrag.