Overview of the Research Initiative
The study “REDEVELOPMENT – Reusing unprofitable and functionally deficient 1950s to 1970s inner‑city office buildings for residential purposes – possibilities and chances” is a research report commissioned by the Federal Office for Building and Regional Planning, Germany. It is authored by Prof. Dr. Gert Kähler (Hamburg), Prof. Dr. Bernd Kritzmann (HafenCity University, Hamburg) and Dipl.-Ing. Carsten Venus (blauraum architekten, Hamburg). The project, part of the Forschungsinitiative Zukunft Bau, investigates the economic, legal and societal dimensions of converting post‑war office blocks into housing, with a focus on sustainability and urban revitalisation.
Research Aims and Methodology
The report aims to determine whether inner‑city residential accommodation can be provided economically by re‑using obsolete office buildings. The authors employed case‑study analysis across several German cities (Karlsruhe, Hamburg, Munich, Frankfurt, Dortmund, Bremen, Kassel, Magdeburg) to assess conversion potential, costs, and regulatory conditions. The interdisciplinary team combined architectural history, design expertise and economic modelling, consulting external specialists to avoid a purely real‑estate‑driven perspective.
Political and Societal Context
Across German political parties, contemporary regional planning prioritises limiting urban sprawl, re‑using existing infrastructure and improving energy efficiency of existing buildings. Demographic trends show a growing “generation 50 plus” seeking centrally located, well‑served housing, as well as higher‑income singles and childless couples preferring vibrant inner‑city locations. These shifts create demand for sustainable, compact residential supply within existing urban fabric.
Legal and Financial Framework
Conversion projects must navigate the “right of continuance” in building permits, ensuring that conversion permits accommodate the same or greater building volume. Flexible municipal planning, including adjustments to zoning, distance, and amenity requirements, is essential. Financially, the report contrasts demolition‑and‑new‑construction with conversion, noting that conversion can be cheaper due to avoided demolition costs and shorter construction periods, despite comparable total investment.
Cost Data and Economic Findings
Characteristic cost data from the case studies indicate restructuring costs ranging from €5 – 15 per square metre, with total floor areas between 1 200 m² and 15 600 m². For example, Hamburg City Hof shows restructuring costs of €903.3 /m² for 15 600 m², while Frankfurt’s Mosel‑/Niddastraße averages €530.8 /m² for 1 300 m². The authors highlight that conversion costs can match new‑build costs, but the absence of demolition expenses and reduced financing periods improve overall economic viability.
Sustainability and Environmental Benefits
Re‑using existing office structures aligns with ecological objectives by preventing further urban sprawl, reducing construction waste and conserving embodied energy. The report stresses that retrofitting older buildings to meet modern energy standards is technically feasible, with possibilities for thermal insulation, renewable energy integration and upgraded fire‑safety systems. These measures support EU climate goals and promote circular construction practices.
Design and Technical Considerations
Successful conversion requires adequate ceiling heights, structural stability and adaptable building systems. The authors note that many 1950s‑60s office blocks possess sufficient technical capacity for residential adaptation, provided comprehensive restructuring is undertaken. Design solutions often involve “new‑old” concepts, preserving volume while reconfiguring internal layouts to meet contemporary living standards.
Market Outlook and Future Trends
The report anticipates an increasing supply of convertible office buildings as companies adopt flexible, globalised operating models and as the German REIT market matures. Economic crises tend to accelerate the shift toward portfolio‑based asset management, prompting owners to seek higher‑value uses such as residential conversion. Demand is expected to grow, especially among middle‑ and upper‑class households that revitalise city centres and stimulate local economies.
Regional Implications and Policy Recommendations
The authors conclude that no single solution fits all conversion projects; decisions must consider local legal conditions, building age, preservation status and market demand. Public authorities are encouraged to provide supportive frameworks, including subsidies, streamlined permitting and incentives for sustainable redevelopment. Such policies can help meet housing shortages while advancing environmental objectives across Europe.