The building sector is one of the most important sectors for material demands in Germany. Construction and demolition waste account for by far the largest share of waste generated in Germany. At the same time, the building sector causes enormous amounts of Greenhouse gas emissions, both directly and indirectly. These significant environmental impacts of the building sector necessitate a transformation towards a resource- and climate-friendly building sector.
An important lever in this regard is the increased use of existing buildings, including through the increased reuse of building materials and components, as well as improved recycling. However, there's not enough info available on this. Although many research institutions, universities and companies are investigating the materials used in different buildings, and construction and demolition waste is continuously monitored, there's still a lot of catching up to do in terms of improving the amount and quality of data, as well as systematically collecting and making it usable.
This raises particularly the following questions: What are the origins of the materials used? How long do they remain in the building during its service life? What happens to them after deconstruction? And above all, how can the amount of materials that become waste be effectively reduced?
Answers to these questions are compiled in the project "Circularity of the German Building Sector", conducted on behalf of the German Energy Agency (dena). The researchers at the Wuppertal Institute systematically evaluated information from available studies and literature sources and assessed its quantitative significance in terms of the amount and diversity of materiality in the building stock. The results were prepared and consolidated in a practice-oriented form so that the methodology used can also be utilised and applied by actors in the construction industry.
The study also identifies key barriers and formulates recommendations for action based on these barriers, such as how both the data situation and the practical actions of stakeholders in the construction sector can be improved to increase recyclability and promote circular business models.