Our guest article in the current issue of ECONO

In the past few weeks, two press releases caught our eye: The Association of the German Automotive Industry (VDA) reported that the EU needed an “agency for strategic raw materials” to ensure raw material security along value chains. A week later, the KFW Bank published a study with the thesis: Germany is facing an “era of declining prosperity”. Two reasons were given: the lack of skilled workers and “threatening conflicts over scarce resources”. This is a visible development that studies have been predicting for a long time. Multiple global crises have triggered volatile price fluctuations in recent years. They can be understood as an anticipation of long-term developments that threaten the raw materials markets. The European Union has also put the topic of circular economy on its agenda. The EU taxonomy and the likely revival of certificate trading also increase the risk that “stranded assets” will arise. And: They revive the debate about what sustainable real estate should be like.In ESG-compliant properties, circular economy principles can be found in the areas of environment (E), social (S) and governance (G), but with different weightings. But anyone who wants to implement a circular strategy will quickly notice how complex and cross-sectoral the fields of action are.In addition, the changes that the economy is confronted with are very fundamental.We are facing a paradigm shift. Our linear economic model is reaching its limits! The transition to a truly circular economy is the basis for a regenerative economic system that intervenes deeply in firmly established structures - and radically changes the way we deal with our planet's limited resources.The building sector plays an important role in this context. It is responsible for over 30 percent of global CO2 emissions, causes over 50 percent of waste and uses over 90 percent of mineral resources. Therefore, the pressure to act when constructing and operating buildings is enormous. But the same applies: For the same reason, the leverage is particularly great in order to reduce emissions and raw material consumption.However, the building sector is a slow industry. As a rule, a lot of capital is tied up for a long time, which limits the willingness to explore new paths. In addition, path dependencies are high and the forces of persistence can be strong to stick to established strategies. Holistic cost considerations that look at the life cycle up to dismantling are the exception today. And CO2 follow-up costs have not yet been priced in, or have been inadequately priced in, but simply to societyburdened. The circular economy has many facets. It's about the conservative use of raw materials and the use of renewable energy, but also about sharing and leasing concepts. In the building sector, preservation and the active reintegration of secondary building materials also play a major role. This means: Building materials are already in our built environment and are used and reused. However, anyone who uses primary building materials on a construction site is also confronted with the fact that CO2 emissions during production and construction are directly related to the question of resources. Renewable building materials play an important role in this. Furthermore, it should be noted that a building is more than just the addition of its materials. Components must be joined in such a way that the installed building materials or components can be dismantled in a pure, non-destructive manner. This is the only way a building becomes a resource store: the building materials used retain their value over the long term and are available to the market again in the future.Example from practice: In Brühl near Heidelberg, a residential area was developed using wooden construction. Our architectural office was commissioned to plan an apartment building. The client is the Schönau Foundation, the largest corporate forest owner in Baden-Württemberg. They also own around 900 residential and commercial units. This project includes four residential buildings designed by four different architects. The foundation wants to strengthen its commitment to housing construction in the Rhine-Neckar metropolitan region. The client attaches particular importance to sustainability and the low use of energy and resources. This particularly affects the “gray energy” of building material production, as well as the operating and recycling phase. The focus is on high living comfort and user-friendliness in mixed apartment types. Part of the project is to carry out a scientific long-term analysis of the various timber construction methods and energy concepts. In this way, the foundation makes an important contribution to climate protection - and is at the same time a pioneer for modern and sustainable construction in the region. In the four-story apartment building, we focused on two key parameters of circular value creationFocus: On the one hand, wood from the client's inventory was used as single-material building elements, in a single-variety and dismantling construction method. On the other hand, we investigated alternative external wall structures to generate direct, passive solar heat gainsto use. For this reason, the ten residential units were built using solid wood construction, with non-glued cross-laminated timber walls and stacked board ceilingswere used. The wood largely comes from the foundation's own regional forestry operation, which has created a regional value chain. A profile glass facade is installed in front of it, which acts as a weathering layer and active energy storage. In winter, the heated air serves as a kind of thermal insulation; in summer, the circulating air cools the wall surface. This facade principle does not require traditional thermal insulation and still meets all the requirements of the Building Energy Act (GEG). The wooden surfaces of the unglued external walls, which are fastened with wood screws, remain visible behind the profiled glass facade. The consistently holistic development of the building in an integral planning process means that essential building elements can be kept in material cycles in the long term, instead of creating waste during conversion or dismantling and thereby destroying resources. The glue-free design makes it possible to return these components to the biological cycle without any harmful substances. The profile glass facade can be reused as a building element or completely recycled as a material. The CO2 impacts or the CO2 stored in the construction can be quantified using a life cycle assessment. This information could ensure appropriate funding for a building resource pass, which is currently being discussed at the federal level. The value of the materials used leavesidentify themselves via digital interfaces for BIM planning (“Building Information Modeling”). This information provides important information on how to value a property in monetary terms in the long term. If circular design principles are consistently implemented, added value can be created for existing owners. Buildings become “material banks”: Instead of continuing to be part of the problem, they become part of the solution!