Building in Existing Structures

Ambitious Goals: The Climate Protection Act sets the target of reducing greenhouse gas emissions in Germany by 65% by 2030 compared to 1990 levels and achieving climate neutrality by 2045 (Source: German Federal Government). In addition, the Paris Climate Agreement aims to limit global warming to a maximum of 2 °C, ideally 1.5 °C (Source: German Environment Agency).

The building sector plays a decisive role in achieving these climate goals. Building in existing structures can be an important solution. Preserving, upgrading, and repurposing existing buildings and construction stock offers enormous CO₂ savings potential. The embodied energy—the energy already invested in construction, manufacturing, and transportation of building materials—remains stored in the existing structure. Consequently, a building’s sustainability is not only determined by its current energy consumption but also by the embodied energy already locked into its materials. Demolition and new construction consume a significant amount of energy. For new buildings, embodied energy accounts for about 50% of the life-cycle energy use (KfW55) (Source: Bauwende). Therefore, modernization of existing properties offers high CO₂ reduction potential. Through maintenance, renovation, or adaptive reuse, buildings can be upgraded and aligned with future requirements. Building in existing structures provides the opportunity to make a building or urban space fit for the future.

In addition to climate goals, the German government aims to create 400,000 affordable and climate-appropriate housing units per year (Source: German Federal Government). In times of housing shortages, it is necessary to maintain and reuse existing structures. Sustainable renovation can give buildings a second life and new functions.

Equally important is the energy-efficient renovation of existing buildings. Calculations from the Research Institute for Thermal Insulation assume that the climate targets can only be achieved if the modernization rate is increased to at least 2% annually (Source: Forschungsinstitut für Wärmeschutz e.V. Munich). Currently, the renovation rate is only about 1% (Source: German Environment Agency). Therefore, the annual rate must be significantly increased. In July 2022, the Federal Ministry for Economic Affairs revised the Federal Funding for Efficient Buildings (BEG). For complete renovations, applicants can apply to the KfW development bank. To allow funding for as many applicants as possible, KfW reduced the BEG subsidy rates (since 15.08.2022). For individual measures—such as window, door, or heating replacements, or building envelope renovations—the Federal Office for Economic Affairs and Export Control (BAFA) is responsible.

Conclusion:
Before demolishing and rebuilding a property, the question should always be asked: What can the existing building do, and how can we use it in the future? Existing potential should be utilized and qualities strengthened. Architecture is also a record of its time, worth preserving and guiding into a new life cycle. To contribute to climate protection targets, it is essential to value existing buildings and adapt them for contemporary use. Sustainable construction does not exclusively mean building new structures—it also means preserving and enhancing the existing building stock.

Our Examples:
Goldsteinstraße, Frankfurt am Main
Heinrichstraße, Düsseldorf