Building values

Rethinking decisions on demolition and reuse by (re)valuing existing buildings

The construction sector is a central arena of climate policy, still responsible for major emissions and waste. Yet decisions on existing buildings remain dominated by demolition and new construction, as political instruments and valuation models rarely acknowledge the wide potential of reuse. The values inherent in existing buildings – from embedded resources to cultural and social qualities – are often overlooked.

The project therefore examines how such decisions are shaped by legal frameworks, market-based valuation practices, and institutional logics. Building on this analysis, it develops an integrative evaluation framework that incorporates multiple dimensions of value and seeks to establish reuse as a legitimate and sustainable option in urban development.

  • demolition vs. reuse
  • decision-making logics
  • valuation practices
  • building performance and structural lifespan
  • norms, laws, and institutional frameworks
  • embedded resources and embodied energy

Context

Accounting for 37% of global energy- and process-related CO2 emissions1 and producing more than 198 million tonnes of construction and demolition waste annually in Germany,2 the building sector is one of the most resource-intensive arenas of climate policy. Sustainability debates increasingly highlight circular methods and innovative materials, while the ‘climate-relevant, social, architectonic and urban planning potential’3 of existing buildings and reuse remains widely overlooked – both in political steering mechanisms and in established evaluation models. Demolition and replacement still dominate as default solutions.

In the German context, a framework that integrates different evaluation logics and establishes reuse as an independent, future-oriented planning option is still missing. Existing approaches – from market-based real estate valuation over environmental life-cycle assessments to culturally and historically oriented heritage protection – capture only isolated aspects and rarely offer a holistic view. Beyond these valuation practices, demolition or reuse decisions are also shaped by laws, building codes, and institutional routines, which often create systemic barriers to reuse. These shortcomings underline the need for a more comprehensive approach to evaluation and decision-making in dealing with building stock.

Aims

Situated at the intersection of civil engineering, valuation research, and urban sustainability debates, the project addresses a largely neglected dimension of transformation: not the visible change of the built environment through new and different construction, but the shift in evaluation standards and decision-making logics towards recognizing reuse as a viable option.

The dissertation pursues three complementary objectives:

  • First, to establish a macroscopic overview of the German building stock, its age structure, demolition patterns, and the actors and debates that shape its perception.
  • Second, to analyse the decision-making and evaluation logics that determine whether existing buildings are demolished or retained – including legal frameworks, building codes, valuation systems, institutional routines, and societal perceptions – in order to uncover systemic barriers and identify neglected values.
  • Third, to synthesize these results into an integrative evaluation framework that combines technical performance, structural lifespan, embedded resources, and embodied energy with ecological, economic, social, and cultural dimensions. The framework highlights neglected values, reframes the inherent potentials of existing buildings, and provides alternative criteria for their assessment.

Research design

The dissertation applies a sequential, qualitatively oriented mixed-methods design in three stages that mirror its main objectives.

Stage 1 – Contextualization: defines the research field by examining the German building stock and its current treatment, using secondary data analysis and network analysis. This creates an empirical basis for the subsequent stages.

Stage 2 – Analysis: focuses on understanding decision parameters such as regulation, evaluation systems, and conflicting interests. Methods include literature and policy reviews, comparative assessment of building evaluation approaches, and expert interviews.

Stage 3 – Transformation: finally synthesizes the findings into an integrative evaluation framework with equal terms for existing buildings to reframe evaluation practices. Its relevance and applicability are tested through a second round of interviews with key stakeholders.

By linking descriptive, analytical, and transformative perspectives, the research design reflects the project’s overall aims: to build a contextual basis, critically analyse decision-making logics, and ultimately reframe the values of existing buildings in order to strengthen reuse as a legitimate and sustainable strategy in urban development.

Supervisors: