"We cannot continue as before."

And how did you join the Landmarken family?

I know many developers. Landmarken caught my attention because they have made many forward-looking decisions in recent years. The contact with Moringa came about through Vanja Schneider, whom I know from previous joint projects. What I appreciate about him, apart from his professionalism, is his pioneering spirit. Because we know that humans are not capable of responding adequately today to dangers that lie in the future. It doesn't fit with our way of thinking and our senses. Humans only really react when the saber-toothed tiger jumps out of the bush in front of them. Moringa sets ambitious goals, and I want to work to ensure that we anticipate the right things today.

Which issues are most important to you?

Circular economy and climate adaptation. Incidentally, both topics are directly related. A functioning circular economy would drastically reduce_{CO2 emissions} and thus help the climate. Here, too, we need to anticipate how this will be regulated in a few years' time in the form of building codes and other regulations so that we can find and implement the right solutions now.

Why hasn't this already been done on a large scale?

Because many of the measures are currently suspected of driving up costs. This is only true to a limited extent and, moreover, is constantly changing. In one of our projects, we wanted to use recycled concrete. First, we were told that it was not available, then that it was twice as expensive, and in the end, it was possible to use it at a reasonable additional cost. But there are also countless small things that cost nothing and have a positive overall effect. A bathroom faucet with a flow rate of six liters per minute, for example, doesn't cost a cent more and contributes significantly to conserving water resources.

Where do you see the greatest leverage?

The circular economy will ensure that raw materials are permanently available at reasonable prices and that we move a step closer to a world without waste. If we want our neighborhoods and cities to still be livable in 20 or 50 years, we need to make sure they become greener now. Trees are the air conditioners for outdoor spaces. We will have no choice but to sacrifice parking spaces in public spaces in favor of more greenery. In Vienna, there is the "Raus aus dem Asphalt" (Out of the Asphalt) initiative. In Amsterdam, entire streets are being converted into residential areas, e.g., in the De Pijp district. Of course, this is more bicycle- and pedestrian-friendly, but it also breaks up the concrete and provides more green space. We need to green flat roofs as much as possible. We need to combine green roofs and photovoltaics, decentralizing the energy supply to a certain extent. If we increasingly use heat pumps, this means nothing other than heating with electricity.

And this electricity has to come from the solar roof above?

At least part of it. It's not just a problem of getting renewable electricity from Schleswig-Holstein to Bavaria via long transmission lines. It's also difficult to get the electricity into the local distribution networks within a city, where capacities are also limited. If I produce and consume decentralized, I don't put a strain on the grid.

Some people ask: What should I choose, a green roof or photovoltaics?

Both! The problem with photovoltaics is that if I install a system directly on a dark flat roof, that roof will heat up extremely and thus greatly reduce the efficiency of the solar system. People then wonder why the reality is worse than the previous calculation. If, on the other hand, I install the PV system on a green roof, I have a much higher efficiency.

Other advantages of a green roof include the reduction of heat islands, rainwater retention, and the improvement of biodiversity.

Exactly. There's a casual saying: every flower counts. When you observe that insects are going out in search of pollen earlier and earlier in the year because it's getting warmer earlier, but there are no flowers to be found, you can imagine that the need is great.

In addition to the energy resources consumed in the operation of buildings, we also use a huge amount of materials in the construction of real estate—how can waste be avoided here?

When I was born in 1956, there were fewer than four billion people living on Earth; today there are over eight billion. At the same time, despite all the poverty, prosperity is also increasing. Population growth combined with a high rate of urbanization has led to global construction activity with a gigantic appetite for resources. Currently, the equivalent of New York City is being built every month around the world. This cannot work in the long term with a linear economy. We can no longer continue with this principle of "take, make, waste."

In other words, the linear principle of taking, using, and then throwing away. So the solution is the circular economy, in which resources can be used as raw materials for new, pollutant-free products after they have been used?

Yes, but first we need to rediscover the principles of simplicity and durability. Real estate must be designed in such a way that it can be used not only for 50 years, but also for 100 or 200 years with adjustments and modifications. Only then does the issue of recycling come into play. The circular economy contributes significantly to decarbonization. To achieve this, planners must design buildings to be dismantled so that raw materials can be extracted as easily as possible. They must be non-toxic and sorted by type so that they can be reintroduced into the cycle . This already works very well with aluminum, which has a high recycling rate. Molten scrap aluminum leaves a much lower_{carbon footprint} than aluminum extracted from aluminum ore, bauxite. This is nothing new for wood either. There are entire business sectors that reuse waste wood from demolished wooden houses for higher-value purposes, such as furniture construction.

The federal government is planning to introduce a building resource passport; it's in the coalition agreement. What does that mean?

Yes, it will come during this legislative period—I'm sure of that! This means that we will have to identify the resources used in all new buildings. Greenhouse gas emissions, waste generation, pollutants, the circularity index, and a few other things also have to be reported. There are digital tools for this that keep it from becoming a bureaucratic nightmare. The magic word is "digital twin."

Is it also possible to determine the materials used in existing buildings?

Yes. If you know the year of construction, the type of use, and the converted space, you can determine the material composition of the building with relative precision. We know how buildings were constructed in which decades. There may be deviations, but a relatively precise statistical approximation is possible and very useful.

How important is this data for the resource transition?

The circular economy will only work in conjunction with digitalization. I am also an ambassador for the Dutch Madaster Foundation. Madaster has created a cloud platform on which resource passports are digitally registered. In addition to calculating gray energy, the circularity index is also determined. The financial evaluation, i.e., the residual value of the resources, can be determined at any time by linking it to the data model: after construction, at the time of sale, after the first renovation ten years later, after revitalization in 50 years, or when the property has to be demolished. In this way, the building becomes a raw material store. We are working to ensure that this is also taken into account in the valuation of real estate, similar to the land value.

This is an important point, because at the moment, the construction of a circular building according to the cradle-to-cradle principle (C2C) is significantly more expensive. This should then also be reflected in its subsequent value.

The market still has to adjust to this. This also applies to suppliers, i.e., manufacturers and the construction industry. We are still suffering from the fact that there are simply not enough products on the market. If only one C2C-compatible product is available in a particular material class, then the supplier of that product has a lot of freedom in setting the price. However, there is now no manufacturer, regardless of the product, who is not working intensively on this issue.

You also deal with the topic of system construction. What role will this play in the future?

I firmly believe that system construction is a solution for a wide range of construction tasks. System components are easy to transport. The big advantage lies in the intelligence of these systems and their consistent implementation. There will be more system construction in the future, using wood, steel, and concrete. This is because cement production, currently one of the largest_{CO2 emitters}, will also make its building materials more climate-friendly through changed processes. The same

applies to steel.

But doesn't system construction threaten to make designs boring?

Not at all! If the system is consistently implemented in the areas of structural engineering, technical shafts, vertical access, wet rooms, floor height, and building depth, then a high degree of individuality can be achieved in the building envelope. I have already had some very positive experiences with HPP in this regard. With its Spirit Offices product, Landmarken is also creating individual designs using system construction. You can creatively define parameters that are also based on location-specific or natural phenomena and create an attractive building envelope with just a few different facade modules. Because there's one thing we don't want: buildings that are boring, grid-like structures.

Another topic you are interested in is complex neighborhood development. What fascinates you about it?

There are many factors. One is resilience. A mixed-use neighborhood is more resilient. If one use no longer works, but the others do, then the entire neighborhood is not "stranded," but can be revived with targeted interventions. Another point is that it is easier to implement energy, ecological, or social issues in a neighborhood than in a single property. In a neighborhood, I have different economies of scale in terms of technology, use, and social issues. Apart from that, I believe it makes sense to avoid long distances in the city. I can't accommodate a daycare center in a manageable property with 20 apartments, but for a neighborhood with 200 apartments, I might be able to find an operator who will do so. This creates shorter distances, and if I can accommodate my children in the same neighborhood where I live or work, that is an advantage that is also good for marketing. Conclusion: Making a small property multifunctional is difficult, but making a larger neighborhood multifunctional is an absolute must!

Further information:
Gerhard Feldmeyer gained his expertise working for internationally renowned architectural firms. After a year in Tokyo and several years with Meinhard von Gerkan (gmp) in Hamburg, he spent more than three decades at HPP, where he has been a partner and managing director since 2002. Today, Gerhard Feldmeyer, who is particularly committed to sustainability, complex neighborhood development, and the construction of the future, is also an ambassador for the Madaster Foundation, the global online platform that enables the circular use of materials and products in the construction industry