This paper presents the findings of an interdisciplinary academic exchange exploring the transition towards a circular built environment (CBE), developed over two years of collaborative work at Delft University of Technology’s Circular Built Environment Hub. A key outcome of this work is developing a comprehensive definition of the CBE and the related Scales to Aspects model, which connects the multi-scalar and cross-disciplinary nature of circularity, ranging from materials and components to buildings, neighbourhoods, cities, and regions. It highlights critical tensions, such as the lack of integration between circular strategies and other global challenges.

Adaptive reuse of buildings offers a sustainable strategy for reducing global CO2 emissions by repurposing existing structures, conserving resources, reducing the need to extract new materials, and minimizing waste. However, the decision-making process in adaptive reuse projects is often complex, involving conflicting criteria and diverse stakeholders. Current approaches tend to polarize alternatives, focusing either on broad functional use or specific design options, which can limit decision effectiveness and quality. This study addresses these challenges by developing a participatory mixed-methods approach that integrates Cross-Impact Balance (CIB) analysis with creative scenario-building techniques, including generative AI and participatory workshops. This approach balances the extremes of current decision-making processes, offering a more comprehensive overview of desirable futures for decision-makers. The methodology was applied to create 15 “big picture” circular adaptive reuse scenarios, each incorporating circular building adaptability (CBA) strategies, and enriched with AI generated narratives and visualizations. These scenarios provide stakeholders with a nuanced understanding of potential future pathways, enhancing decision-making processes. This mixed-method approach demonstrates the potential of participatory CIB scenario development in advancing circularity, offering a valuable tool for navigating the complexities of adaptive reuse decision-making.

Purpose: This study assesses the success of a real project in practice, using identified success factors from recent systematic literature. It investigates how theoretical insights translate into real-world outcomes by answering the question: “How do success factors identified in existing literature contribute to the success of a real-world adaptive reuse project?”. Design/methodology/approach: This research utilizes a case study methodology to explore the adaptive reuse phenomenon through the lens of the Fenix I in the Netherlands. Three comprehensive semi-structured interviews with key decision-makers provide insights into experiences, challenges, and ultimately the evaluation of success factors in practice. Data analysis involves deductive coding, systematically organizing success factors into ten categories derived from the literature, to implement the analysis and align with the research objectives. Findings: The results demonstrate the application of a majority of success factors identified in literature within the case study. This study reveals differences in the levels of significance among these factors, their categorization and their existence, particularly between listed and non-listed heritage buildings. Moreover, it shows the remarkable impact of public-private collaboration from the early stages of decision-making through project implementation. The study confirms that a successful real-world project addresses a significant proportion of the success factors identified in the literature. Originality/value: This research facilitates the decision-making process for stakeholders and practitioners in adaptive reuse projects, aiming to foster the development of more successful initiatives in this field.

Background and aim. Adaptive reuse enhances circularity by repurposing buildings, reducing carbon emissions, and preserving heritage. However, decision-making is complex due to stakeholder conflicts, regulations, and uncertainties. This study introduces an integrated framework combining Cross-Impact Balance (CIB) analysis, the Analytic Hierarchy Process (AHP), and Fuzzy-TOPSIS to support structured, participatory decision-making.

Methods and Data. A mixed-method approach integrates CIB for scenario development, AHP for stakeholder-driven prioritization, and Fuzzy-TOPSIS for ranking reuse scenarios. A hypothetical case study demonstrates the framework’s applicability.

Findings. The integration of CIB, AHP, and Fuzzy-TOPSIS provides a structured decision-making approach that enhances scenario coherence, aligns decisions with stakeholder priorities, and improves scenario ranking robustness. The framework enables systematic exploration of adaptive reuse scenarios, ensuring alignment with stakeholder objectives.

Theoretical / Practical / Societal implications. Theoretically, this study advances scenario-based decision-making by integrating scenario development and decision-making approaches, addressing gaps in adaptive reuse decision frameworks. Practically, it provides policymakers, urban planners, and developers with a structured tool to navigate complex decision-making in adaptive reuse projects. Societally, it supports sustainable and inclusive urban development by fostering consistent, long-term strategies that balance environmental, economic, and social considerations.

Circular and adaptable strategies in building reuse are key to achieving a resource-efficient and future-proof built environment. Despite significant advances in circular building research, this field is affected by a significant theory–practice gap. To bridge this gap, we applied an action design research methodology, implementing a circular building design framework over a five-month period in the context of a Dutch monumental office building reuse. The objective of these interventions was to observe practitioners engaging with the framework and identify the barriers they encountered when considering and applying circular building strategies. We observed that the framework primarily functioned as a descriptive tool. Enhancing its usability and effectiveness required several refinements, including simplifying its self-description, clarifying its strategies through practical solutions and connections to related models, providing robust assessment tools, and improving its accessibility. Through iterative action research conducted during the observation and intervention period, we addressed these issues and advanced the framework. Our design-oriented approach led to the development of key design artifacts: a prescriptive guiding, assessment, and reporting tool; a stepwise approach to streamline application; and a hands-on worksheet for practitioners. These artifacts were integrated into a user-friendly platform, transforming the framework into a practical tool for real-world implementation. For theory, this study incorporates a circular perspective into a usable framework and demonstrates how an action design research approach can co-develop and improve frameworks and their usability and relevance. For practice, the produced artifacts represent boundary objects tailored to practitioners’ needs; thereby paving the way for future circular adaptive reuse. Clinical trial number: not applicable.

Over the past two decades, research promoting a sustainable built environment has pioneered new horizons to accelerate the transition to a circular economy. Yet, these efforts are suffering from a significant theory-practice divide. This article offers three interconnected research themes to bridge this gap: 1. Distinguishing circularity practices across spatial and time scales; 2. Redesigning the value of design and its process; and 3. Learning from sister transitions for acceleration.

Despite the significant growth of the literature on adaptive reuse, little is known about the specific criteria unfolding throughout the different phases of the adaptive reuse decision-making process. To address this gap this paper aims to provide a comprehensive, state-of-the-art overview of the decision criteria for adaptive reuse throughout the adaptive reuse process. Through an integrative literature review with a systematic search strategy, three phases are substantiated: pre-project phase, preparation phase, and post-completion phase. This paper finds that despite the similarities between the different phases, with a predominant repetition of economic and architectural categories, more specific environmental decision criteria are still overlooked. The findings underscore the necessity for additional research on circularity within the adaptive reuse process, emphasizing the significance of the often overlooked implementation phase, crucial for practices like disassembly. By offering a novel process perspective on AR decision-making, this study contributes to the growing discourse on adaptive reuse and provides a basis for further enhancement of AR decision-making frameworks.

In recent decades, various programs have been developed as part of Chile’s housing policies to respond to the housing deficit. Most policies have so far focused on addressing the quantitative, qualitative, and urban deficits, neglecting the social dimension of housing. At the same time, the concept of collaborative housing has been referred to as a possible alternative to respond to these social challenges by fostering social cohesion, collaboration, and mutual aid. This article explores how collaborative housing can tackle the social deficit of housing. Here, we conceptualise this deficit as ‘the lack of non-physical or intangible social characteristics given among residents of a project, such as trust, social cohesion, and a sense of community, necessary for housing to be considered adequate.’ We examined the relation between these two concepts by developing a theoretical and empirical study. The first consisted of a theoretical framework and a review of literature on collaborative housing’s response to the social deficit of housing. Second, we interviewed stakeholders from two study cases. We found that residents in both collaborative housing cases perceive an improvement in their social interactions, sociability, trust, and sense of community in their current homes compared to previous homes. Therefore, we conclude that collaborative housing presents opportunities to tackle the social deficit of housing.

In this deliverable, we will briefly introduce circular building strategies and explain business models associated with CHARM strategies. An overall mapping will be presented on the sustainable business canvas based on the outcomes of related work packages.

Purpose
Circular building adaptability (CBA) in adaptive reuse – building transformation – projects can facilitate a resource-efficient and futureproof redevelopment of the built environment. However, there has been a lack of practical tools that guide practitioners on how to foster CBA in adaptive reuse. Therefore, this study aims to collaboratively develop a guiding framework for CBA in adaptive reuse (CBA-AR) projects in general. The CBA-AR framework is a descriptive and content-oriented synthesis mapping a series of strategies to the CBA determinants alongside their enablers and inhibitors.

Design/methodology/approach
A participatory research-oriented approach was followed. First, an archival research was conducted to develop the CBA-AR framework based on literature review and case studies. Second, two co-creation workshops, triangulated with structured interviews, were conducted to validate and expand the framework.

Findings
The first version of the CBA-AR framework comprises 30 CBA strategies. It also brings seven enablers and six inhibitors together with the 30 CBA strategies. The outcomes of the participatory approach contributed to refining and expanding the framework. The final of the CBA-AR framework version comprises CBA 33 strategies. This version brings 10 enablers and 7 inhibitors together with the 33 strategies.

Practical implications
This framework can be used as a guiding and reporting instrument by designers and property developers while transforming vacant or obsolete properties in the Netherlands. Policy makers can refer to this framework and amend adaptive reuse legislation.

Originality/value
The CBA-AR framework can introduce a transformative change in theory and practice, as it is based on theoretical, empirical and participatory research.

While circular business models are receiving increasing academic attention, the business models of real circular building companies remain underexamined. This paper builds upon existing conceptual proposals and general overviews of reuse actors to investigate how these organizations capture and create value within the constraints of the marketplace. Using data from case studies of 25 organizations involved in the reuse of construction waste streams, the business model of each case is described and compared using Osterwalder and Pigneur’s Business Model Canvas. The authors propose six categories of circular construction business model types: upcyclers, component-specific suppliers, material resellers, reuse platforms, reuse consulting offices and deconstruction companies. The key findings include the studied organizations’ consolidation of multiple waste and new product streams, the strategic minimization of hard assets, the cultivation of diverse revenue streams and an emphasis on private market solutions.

It is recommended to integrate specific management competencies in academic education to support the transition towards environmentally sustainable practices, particularly in the construction and real estate sector. This paper explores how architectural management education can integrate environmental sustainability within its current university programmes. In recent years TU Delft explored and experimented with various education initiatives to bring forward environmental sustainability knowledge and to connect with policy, societal and industry practices. This paper describes what we learned from both bottom-up and top-down initiatives implementing environmental sustainability in construction and real estate management education. Bottom-up educational initiatives show that knowledge about transition policies, stakeholder experiences, business models and management practices from a European perspective can help students across the globe to apply knowledge into their local context, reflecting on the overarching management principals across stakeholders, institutions, academic disciplines and cultures. Top-down initiatives show that the university has a vision on integrating sustainability in its curriculum, but that integrating environmental sustainability in construction and real estate management education is still challenging. Adapting the academic curriculum to integrate building and portfolio responses to environmental challenges might be a way forward and the experiences from numerous elective courses and educational initiatives can be a basis to identify the development of a future standard curriculum.

In this deliverable we give guidance for housing associations for circular asset management. The guidance is based upon the circular asset management practises of the CHARM partners, demonstrating circularity in renovation and new construction projects, and the development of material exchange platforms (MEPs). Also, general insights in circular asset management practises have been used. [...]

The built environment plays a crucial role in the ongoing challenge of climate change, primarily through resource consumption, energy use, and contributions to greenhouse gas (GHG) emissions. As urbanization accelerates, the environmental footprint of construction and building operations has grown significantly. Currently, buildings account for 40% of the world’s waste, 40% of material resource use, and 33% of human-induced emissions.

In this deliverable, we briefly introduce material exchange platforms (MEPs) and explain business models associated with CHARM MEPs. An overall mapping will be presented on the sustainable business canvas based on the outcomes of related work packages.

Bevolkingsgroei, marktdynamiek, vastgoedleegstand en veroudering van gebouwen zijn enkele aanleidingen voor transformatie van gebouwen. De laatste decennia zijn er al veel transformatieprojecten uitgevoerd, mede als oplossing voor leegstand (zie 11. Transformatiemeter kantoren). Sinds kort wordt gebouwtransformatie ook als een veelbelovend onderdeel van de transitie naar een circulaire economie gezien, omdat er per definitie sprake is van hergebruik van materialen en producten en dit de noodzaak om nieuwe materialen in de kringloop te brengen vermindert. Om een optimale bijdrage te leveren aan de circulaire economie, zullen de gebouwtransformaties zelf evenwel ook circulair moeten worden uitgevoerd. Dit hoofdstuk presenteert daarom een conceptueel model voor praktische en toepasbare strategieën voor circulaire en aanpasbare gebouwtransformatie. Dit model is een handig en informatief hulpmiddel voor beleggers, ontwerpers, ontwikkelaars en bouwers.

Building costs play a significant role in determining the affordability of a housing project, and these depend to a large extent on design choices. This paper is based on the premise that collaborative design processes, or co-design, used in collaborative housing (CH) in Europe reduce building costs and consequently increase the affordability of these housing projects. However, research remains scarce on the extent to which CH is an affordable solution from a design perspective compared to affordable mainstream housing (MH), in which no co-design is used. Therefore, this paper aims to fill this knowledge gap by assessing the impact of design choices on building costs in CH and MH. To this end, we developed a simulation model to compare the building costs of CH with MH based on their design choices. Findings indicate that CH represents a more affordable and space-efficient solution when compared to MH, if we look at the building costs per unit. This is because CH provides less expensive units while it includes larger common spaces and extra quality. These results help to refute existing claims about the unaffordability of CH design solutions.

Research on the circular built environment has to date focussed mainly on technical aspects of circularity in the built environment, emphasising the development of methods, tools, and frameworks to facilitate technical solutions that can narrow, slow, close, and regenerate materials cycles. Despite progress made in understanding the technical possibilities of circularity in the built environment, and although there has been longstanding acknowledgement that new forms of inter- and transdisciplinary collaboration are needed to accelerate and scale up solutions for the circular built environment, studies have also consistently highlighted the lack of collaboration as a significant barrier. In this position paper, we argue that existing research tends to focus on collaboration at the level of the building project, and this neglect calls for developing longer-term collaboration for circularity as a multi-level transition that considers the interactions between multiple parties involved in extended and multiple product lifecycles traversing multiple scales beyond the building project.

Population growth, market volatility, building obsolescence and property vacancy are triggers for adaptive reuse. Thus, adaptive reuse is an investable practice that needs to be facilitated by the means of adaptable design. Furthermore, adaptive reuse aligns with the principles of circular economy (CE), as it promotes the reuse of buildings and their longevity; thereby, reducing the need for new materials. In this regard, promoting the so-called circular building adaptability (CBA) in adaptive reuse could provide different benefits to the built environment, including long-lasting functionality and material reversibility. However, no guiding tool has been developed yet to practically guide practitioners on how to promote CBA in adaptive reuse. Therefore, this study aims to develop a guiding framework for CBA in adaptive reuse. First, a content-wise guiding framework was synthesized based on lessons learned from the relevant literature and case studies. The framework brings together a series of passive, active and operational strategies alongside their enabling and inhibiting factors. Second, a co-creation workshop was conducted and triangulated with three interviews to validate and expand the defined strategies. Based on the findings of this participatory approach, the developed framework encompasses 33 strategies. This framework can be seen as a legitimate and informative tool for practitioners, as it was constructed based on acquiring knowledge from theoretical research, empirical research and participatory research.

Passports for circularity, e.g., digital product passports and material passports (MPs), have gained recognition as essential policy instruments for the Circular Economy goals of the European Union. Despite the growing number of approaches, there is a lack of knowledge about the data requirements and availabilities to create MPs for existing buildings. By deploying a mixed-method research design, this study identified the potential users and their data needs within the context of European social housing organisations. Three rounds of validation interviews with a total of 38 participants were conducted to create a data template for an MP covering maintenance, renovation, and demolition stages. This data template was then tested in a case study from the Netherlands to determine critical data gaps in creating MPs, including, but not limited to the composition of materials, presence of toxic or hazardous contents, condition assessment, and reuse and recycling potential of a product. Finally, an MP framework is proposed to address these data gaps by utilising the capabilities of enabling digital technologies (e.g., artificial intelligence and scanning systems) and supportive knowledge of human actors. This framework supports further research and innovation in data provision in creating MPs to narrow, slow, close, and regenerate the loops.