Collective self-organized and participatory forms of housing are re-emerging across Europe. In Amsterdam, the municipality recently launched the ‘Action Plan Housing Cooperatives’, aiming to realize 15–20 cooperative projects by 2030. While the potential of such resident-led initiatives to strengthen the social dimension of housing is increasingly recognized, most research has focused on the ‘use’ phase of completed buildings. However, in the Netherlands, most housing cooperatives are still in the planning and development stage. The thesis investigates how members of cooperatives experience social relationships, social interactions, trust, and a sense of community during this development process with particular attention to characteristic elements of cooperative housing and the timing of member involvement.
The research connects theoretical concepts of social cohesion with a qualitative case study approach, including semi-structured interviews with members of two housing cooperatives in Amsterdam. Findings show that collaboration on the project was the strongest and most consistent driver for the development of the social dimension, particularly for building trust and social relationships. General member assemblies, small-group meetings, and meetings in person were central settings for this. Joint activities such as shared meals or workshops reinforced trust and a sense of community during the development phase, even though they often competed with the demands of project work. Stressful shared experiences often created tension in the short term but ultimately strengthened the social dimension. The length and intensity of members’ involvement also played a role. Long-term members did not always experience a stronger social dimension within the cooperative but instead often shifted from a strong focus on social aspects to a more collaboration- and task-driven focus. Cross-cutting themes such as sharing practices, diversity, and collaboration with external stakeholders further shaped the experiences.
The findings underline that the social dimension of resident-led housing can already develop during the planning phase, before members move in together. They suggest practical implications not only for housing cooperatives themselves, but also for municipalities, architects, and developers. Housing cooperatives were found to take on tasks that are often considered municipal responsibilities, which underlines the importance of institutional support to prevent burnout among members and to allow them to focus on community-building. Diversity was experienced as enriching but also challenging, which points to a need for active guidance and support. Finally, the thesis shows that active participation in the development process of housing is central for strengthening social cohesion between residents, raising questions about the potential of resident participation in conventional new housing developments.

In the Netherlands, the built environment is responsible for half of all raw material consumption and contributes 40% of the total country’s waste production. This characterizes the current prevalent unsustainable take-make-dispose process. To address the significant impact, a transition to a circular economy that prioritizes materials and circulates resources is essential, operationalized through the application of circular strategies. Adaptive reuse projects oUer significant potential to support this transition by extending the lifespan of existing buildings. However, existing literature highlights several barriers that hinder the eUective integration of circular strategies in adaptive reuse projects. This includes fragmented collaboration and the absence of structured guidance on organizing the development process. While strong collaboration across the development process is recognized as a key enabler, there is little insight into how it should be organized. This lack of guidance is especially critical in the early development phases, where key decisions are made that shape the project’s potential for circular outcomes. Moreover, the developer’s important role in facilitating collaboration is often approached from a general perspective, without a specific focus on their viewpoint or position. To address this, this research aims to answer the following research question: ‘How can Dutch real estate developers organise the early phases of the development process to support the integration of circular strategies in adaptive reuse projects?’ To arrive at an answer, this research combines theoretical research with qualitative empirical research. A multiple case study is conducted, drawing on interviews and document analysis to provide in-depth insights. A focus group with real estate developers was undertaken to validate cross-case findings and to explore explanations for results not fully captured by theory or cases. The study identifies the distinct role of each early development phase, inception, feasibility, and design, in supporting circular outcomes. It also outlines key circular strategies, actor roles, and phase-specific activities that enable integration of circular strategies in adaptive reuse projects. The findings emphasize that the early development phases do not follow a strictly sequential order. Instead, feasibility and design often progress iteratively, shaped by project-specific conditions and evolving circular ambitions. Furthermore, the study reveals that a developer can play a proactive role by aligning actors with circular ambitions. These insights are synthesized into a normative framework, providing phase-specific guidance for real estate developers in organising the early phases of adaptive reuse projects to support the integration of circular strategies.

The construction sector has a substantial impact on climate change. In the Netherlands, the
construction sector accounts for nearly 35% of the Netherlands’ CO₂ emissions and half of its
resource use. Although Dutch recycling rates are relatively high, the use of secondary materials in new construction is still very low. Given the national ambition to achieve a fully circular economy by 2050, this represents a missed opportunity. Within buildings, structural components account for the largest share of embodied carbon and should therefore be targeted for reuse. Collaboration among key actors in the construction value chain, including actors such as developers, architects, contractors, advisors, and demolition companies, can enable this reuse, but research is limited on this topic.

This research explored how collaboration among the mentioned actors could enable the reuse of structural components from buildings reaching the end of their lifecycle. A qualitative approach was used, incorporating semi-systematic literature reviews, case studies, semi-structured interviews, and workshops. First, the study identified factors that affect the reusability structural components. After this, the study identified barriers and drivers in the reuse process, as well as the collaborative process needed such as roles, knowledge, and workflows. This was followed by a workshop that incorporated these results and identified different strategies for collaboration.

It is found that the key barriers to structural reuse are primarily economic, organizational, and
social, rather than technical. Fragmented information, misaligned timelines, and unclear roles
often hinder the practical implementation of structural component reuse. The resulting strategy guide addresses these barriers and proposes actionable strategies for the early project phase. The guide offers collaborative strategies that embed reuse into the routines, roles, and dynamics of construction projects.

This thesis explores the use of real option valuation to enhance the financial viability of circular real estate by valuing detachable aluminium façade components. The transition to a circular economy in the built environment is hindered by financial barriers: high upfront investment costs, and the absence of mechanisms to capture end-of-life value of building components. By applying option pricing models, including the Black & Scholes (1973) pricing model, binomial tree- and Heston (1993) option pricing, to a case study, this research uses aluminium commodity price data to value the option to recover raw aluminium embedded in a detachable façade system. A parallel qualitative study involving industry professionals assesses the willingness of market parties to adopt the researched valuation methods and to enter option contracts on detachable building components. Results indicate that real option valuation, as applied to aluminium building components, has the potential to fundamentally shift real estate valuation practices by introducing the concept of assessing buildings and components based on the “moneyness” of recovering embedded raw materials. In addition, by assigning a price to option contracts, this method enables both the demand side of building components to benefit from upfront cash inflows and the supply side to hedge against future material price volatility.

The strategic management of real estate portfolios has become increasingly complex due to global challenges such as climate change, scarcity of raw materials, and changing organizational needs. For large-scale portfolios, such as those of the Ministry of Defense (MvD), these challenges are increased by strict operational requirements, financial constraints, and sustainability objectives. This thesis examines the role of the IFR construction method as a tool to enhance the flexibility and resilience of large-scale real estate portfolios.
The research follows a qualitative, exploratory approach. The central question is: To what extent does the F(lexibility) and R(emountability) in the IFR construction method provide a solution to the challenges of Defense real estate, such as political and economic fluctuations and increasing sustainability requirements? Interviews revealed that “flexibility” is treated as a broad, complex, and often ambiguous concept, lacking a shared definition among advisors, managers, and needs assessors.
Semi-structured interviews with stakeholders within the Rijksvastgoedbedrijf (RVB) and the Ministry of Defense (MvD) form the core of the data collection. It appears that ‘flexibility’ is interpreted much broader and more complex in practice than the original hypothesis suggested, ranging from product-focused physical adaptability to process-oriented standardization and rapid operational reconfiguration. This diversity exposed a clear gap between strategic ambition and practical implementation.
These insights have led to a reorientation of the literature study and the development of a new conceptual framework that maps the different dimensions of flexibility in relation to portfolio management. The framework places emphasis on the physical adaptability of buildings as a prerequisite for strategic flexibility, while showing that organizational capacity and TCO-based management are essential to unlock real value.
This framework is tested in a focus group to validate its applicability and relevance. The results not only provide a better understanding of the role of F and R in Defense real estate, demonstrating how IFR can offer strategic advantages in cost control, adaptive capacity, and material reuse, but also guide how circular building principles can be strategically employed in response to political, economic, and sustainability challenges. The study highlights that long-term benefits, financial resilience, operational response, and reduced material waste, emerge only when physical flexibility is paired with agile organizational structures and clear strategic vision.
The findings underscore the crucial role of circular building in achieving long-term resilience in real estate portfolios. Ultimately, the research shows that the strategic value of remountable construction depends not merely on flexible building design, but on integrated portfolio governance that embeds flexibility at organizational, process, and product levels.
This thesis contributes to the broader concept of circular economy by demonstrating how circularity can transform real estate management into a strategic instrument for resilience and sustainability.

In recent decades, the housing shortage and multi-dimensional housing challenges, including lack of physical quality, accessibility to urban amenities, lack of social characteristics and habitability conditions, have increased worldwide. In Latin American countries faced with some of these challenges, many governments have formulated a wide range of policies and housing programs. In Chile, the State has delegated housing production to private companies. This approach has mostly affected the location, quality, and social dimension of housing. In other urban contexts, such as in some European countries, inhabitants facing similar issues have self-organised to develop their homes driven by pragmatic and radical goals. From a Global North perspective, these initiatives, characterised by collaborative processes between future residents and external stakeholders in housing production, are labelled under the umbrella term of Collaborative Housing. In Latin America, there is also a long tradition of self-organisation in housing through self-building and self-management processes. In Chile, there has been recent interest from resident groups, third sector organisations and the current government in promoting collective self-organised housing through specific programs. However, the concept of collaborative housing has been mainly researched and theorised from a Global North perspective. Furthermore, the meaning and potential of collaborative housing to address housing deficits from a multi-dimensional standpoint have received limited attention in academic research in Chile. This PhD research fills this knowledge gap by applying the collaborative housing concept to study collective selforganised housing in Chile. To this end, it proposes a conceptualisation of ‘Collaborative Housing’ in the Latin American and Chilean context and determines its dimensions. It also investigates its opportunities and limitations when addressing the Social Deficit of Housing, plans scenarios, and proposes policy strategies. The research applies mixed methods, including a policy review, case studies, interviews, and Delphi-based scenario questionnaires. This dissertation concludes with scenarios and long-term policy strategies for three collaborative housing models emerging in the country: cooperativas cerradas de vivienda, pequeños condominios, and vivienda colectiva. It also provides recommendations that serve as a guide to stakeholders interested in implementing collaborative housing.

Existing buildings are changing assets, altered in response to various external or internal triggers for change. Often, change can occur in the form of adaptive reuse – also known as building transformation. Therefore, promoting adaptability in transformation is necessary to cope with the inevitability of building changes. Building transformation is considered an effective practice contributing to the circular economy (CE) and building adaptability as a prerequisite for circular design. However, previous research pointed out that building stakeholders lack knowledge about the alignment between CE and adaptive reuse.
This study aims to provide building and real estate practitioners with a guiding framework for promoting circularity and adaptability in adaptive reuse projects. A quadrant research design was used in this study to develop and apply the framework in practice. The four components of this research are four stepwise studies, namely theoretical – an integrative literature review, empirical – multiple case studies, participatory – framework co-development, and actionable – framework implementation.
First, the integrative literature review contributed to theoretically conceptualizing the underlying concept of this research – the circular building adaptability (CBA), which brings together circularity and adaptability. Second, the multiple case studies contributed to extracting lessons learned about applicable CBA strategies in adaptive reuse and their enabling and inhibiting factors. Third, the participatory study contributed to co-developing a descriptive framework for CBA in adaptive reuse (CBA-AR). Finally, the action research study contributed to testing and improving the usability and effectiveness of the CBA-AR framework based on observing, acting, and reflecting on a case project.

In the past the main focus within the world of real estate was on energy performance; a lot of high quality insulation, many solar panels and a super heat pump make sure the BENG-requirements are met. However since we are achieving the BENG more and more easily nowadays, another aspect is becoming increasingly important: the environmental performance. From 2025 residential buildings have to meet an MPG-value of 0.5 €/m2.year, which is expected to be definitely doable for most of them, except for apartment buildings. In the near future the designs of apartment buildings need to be adjusted to decrease the environmental effects caused by the materials during their whole lifecycle. This contains the replacement of familiar traditional materials like concrete for innovative biobased materials for example. Besides, these materials should no longer be demolished after 75 years, but be constructed demountable to make sure they can have a second life. Furthermore form factors will play an important role in this process; lower floor heights, bigger GFA’s and more efficiently shaped footprints are needed to receive the required environmental permit in the future. This report is about the feasibility of apartment buildings meeting an MPG-value of 0.5 €/m2.year and the consequences that go with the improvement strategies that are needed.

According to the United Nations the Poles are melting, rising sea temperatures are killing ocean life, the acidity of sea water is rising and on land forests are burning (United Nations, 2019). This together with industrialization, increased urbanization, increased population growth and unsustainable consumption patterns this has put a strain resources (Ari & Yikmaz, 2020). Circular economy models, in contrast to the linear model, dissociate economic growth from the consumption of primary raw resources. Since the construction sector is still in its infancy with a circular economy, there is a very high potential for enhanced resource reuse, higher use of recycled materials, and increased sustainability (Stroetmann & Huttig, 2020).
The main research question is: “What are the observed and anticipated barriers and challenges for early and potential adopters of Digital Twins technologies in the Dutch circular-built environment?”
The hypothesis of this study is that an organization's circularity strategies are influenced by its specific needs, leading to a perceived need for digital replicas with specific functionalities. This decision, influenced by operational and strategic goals like material durability, environmental harm reduction, and resource utilization, influences the choice of digital twin technology. Companies with complex circularity plans may opt for more advanced digital twins, while those with simpler requirements may opt for more flexible solutions.
The research will employ several methodologies to provide a comprehensive view of digital twins' potential in the circular built environment. A literature review was conducted of CE economy strategies within the built environment. The goal was to identify challenges and barriers in the adoption of digital twins as a tool for circular construction. Semi-structured interviews were conducted to identify barriers experienced by those potentially using these technologies and challenges experienced by those implementing them. The literature review was used to set up a framework for conducting these interviews, categorizing actors based on their roles and circular strategy. The final aspect of the research was the solutions sourced from interviewees, categorized and cross-referencing with barriers. This provided an overview of potential solutions to the barriers and challenges identified during the interview's initial stages, ensuring a critical reflection of the solutions provided.
This thesis explores the barriers and challenges faced by early and potential adopters of Digital Twin (DT) technologies in the Dutch circular-built environment, focusing on Circularity Strategies, Digital Twins, and the unique challenges encountered by adopters. Through a comprehensive analysis of the built environment, circularity strategies, and DT archetypes, the study identifies key factors affecting the adoption process, such as financial constraints, technological hesitancy, data ownership, and regulatory issues. Interviews with early adopters revealed both common challenges, such as standardization and financial limitations, and specific solutions, including leadership in communication, modular technologies, and collaboration with research institutes. Potential adopters, on the other hand, reported additional barriers like technological immaturity and lack of clear business models. The study's findings emphasize the need for continuous technological improvements, the development of financial incentives, and stronger regulatory frameworks. Despite progress in addressing some challenges, significant barriers, such as data privacy and ownership, remain unresolved. The study concludes by offering recommendations for future research and strategies to support broader adoption of DTs, emphasizing collaboration, phased implementation, and a flexible approach to categorizing digital twin practices in the circular-built environment.

Global warming's impacts on ecosystems and economies underscore the urgent need for sustainability in the built environment, particularly in the housing sector, which significantly contributes to greenhouse gas emissions and material consumption. The Circular Economy (CE) presents a promising solution by minimizing resource use, environmental impact, and waste through strategies like slowing, narrowing, and closing material loops. This research focuses on developing a Circular Kitchen (CIK) as a model for circular building components. It targets Dutch Housing Associations for their market influence and long-term investments and involves other kitchen supply chain stakeholders.
The study identifies four key research goals: developing a life cycle costing (LCC) method for evaluating circular components, assessing the environmental and economic performance of circular building components, deriving lessons from stakeholder choices, and examining the feasibility of circular kitchens beyond the CIK project. The findings suggest that while the CIK designs outperform standard kitchens environmentally and economically, real-world application remains challenging. Although the CIK did not reach mass implementation, the insights gained inform the development of more feasible circular building components. This research advances the understanding of CE in the built environment, providing strategies to improve the feasibility and environmental performance of circular building components.

On the real estate market, there will always be a demand for newly constructed real estate. Demand and supply are never quite in balance, meaning that the construction of new real estate will always exist. However, looking for opportunities to satisfy the demand with the existing building stock is often forgotten or neglected. 87% of the needed buildings in 2050 have already been built (Wilkinson & Remoy, 2017). This is why building adaptation is so important. Concepts such as circularity, renovation and adaptive reuse are very important in the real estate market. When real estate is constructed circularly, it is ‘modular and flexible by design where resource loops are closed and human well-being is promoted’ (Leising et al., 2018). Therefore, building adaptation is a circular measure, and building demolition can and should be done circularly as well. Building adaptation and circular demolition are central in this research. Adaptive reuse is part of building adaptation, and means a major change to an existing building with alterations of both the building itself and the function it accommodates, so across-use adaptation (Wilkinson, 2014). Renovation is similar to adaptive reuse, only the function stays the same, so within-use adaptation (Wilkinson, 2014). These concepts all focus on using the existing building stock to satisfy demands, rather than to construct new buildings. Functional, technical, cultural, legal and location factors have been thoroughly mapped out in previous literature to establish what makes a building suitable for transformation or renovation (Ginelli, 2016). However, circularity potential and ways on how to determine circularity potential in building adaptation projects and demolition projects have not been clearly mapped out yet. With circularity becoming increasingly popular because of future goals that need to be met, it becomes important that clear ways to map out circularity potential in such projects are developed. This research fills in this research gap by creating a tool which gives a circularity potential score to existing buildings which will either be adapted or demolished, and shows which circularity measures can be taken. Furthermore, the tool will give indications on potential CO2 emission savings by applying circular strategies. Because there is no one way to approach this, instead of a main research question, a main research aim has been set up: To develop a tool which measures and identifies what the circularity potential of building adaptation projects and building demolition projects is. This tool is originally inspired by the conversion potential meter, developed by (Geraedts et al., 2018). Further on in the research, many extra tools and frameworks inspired the final result of the tool; the Circularity Potential Meter.

The construction sector significantly contributes to global waste generation and greenhouse gas emissions, leading to environmental issues such as climate change, global warming, and resource depletion. The conventional linear economy in the construction sector follows a take-make-waste approach, resulting in adverse environmental impacts. The concept of a circular economy (CE) aims to address these issues by promoting regenerative practices and closing the material use cycle through reuse and recycling. However, many companies hesitate to invest in circular approaches due to higher initial costs and limited knowledge. Consequently, research focusing on understanding the degree of circularity and its financial implications has become crucial in facilitating the global transition towards circularity in the built environment. This research delves into methods aimed at improving the comprehension of circularity in real estate development projects and understanding the associated costs. The primary objective is to devise a circular life cycle cost model (C-LCC) which seeks to bridge the gap between the evaluation of circularity and its financial implications throughout the life of a building. Unlike traditional business cases that only consider initial investment costs and potential revenue from building projects, this innovative model provides a comprehensive tool for evaluating the financial costs and benefits associated with varying degrees of circularity. An extensive literature review and interviews were conducted to establish a solid foundation for understanding the key concepts and principles of the circular economy and its application in the built environment. The developed C-LCC model is applied to a real estate development project, namely Coolbase in Rotterdam, to simulate the financial outcomes of various circular building design scenarios. This improves the understanding of the relationship between circularity and associated finances. The disparate simulations underscore the critical role of building design, material selection, and the degree of building disassembly as principal influences on the level of circularity and corresponding financial implications. The model illustrates the costs and benefits across various stages of a building's lifecycle, including the initial, operational, and end-of-life phases of a construction project, while emphasizing the potential benefits inherent in various circular design scenarios. In conclusion, this study provides valuable guidance for a more sustainable and circular future, with the model providing insight into the potential costs and benefits that depend on the degree of circularity. Moreover, the results can serve as a tool for decision-making for circular choices in real estate development.

A material passport (MP) is a digital document which aims to track the circular potential of building materials. It is seen as a key enabler for a circular economy (CE) in the building sector. The construction industry is one of the most resource-intensive industries which produces massive amounts of construction and demolition waste (CDW). Shifting the construction sector from a linear to a circular model has been gaining increasing attention recently. Re-use of materials in existing building stock to prevent further depletion of natural resources is seen as one of the means to transition the sector towards a CE. Research in this area has been focused on the potential and opportunities of digital technologies in the reuse of materials, but there is a lack of research on the implementation of MPs by key stakeholders in practice.

This research aims to gain insight into key stakeholders’ perspectives regarding current data exchange practices. The guiding research question for this thesis is “How can the data accessibility and interoperability of Material Passports be optimised in order to improve the effectiveness of its implementation within practice?” It is answered with the help of four sub-questions. The first sub-question aims to gain an understanding of the key concepts and characteristics of MP data exchange with the help of a literature review. This is followed by the second sub-question which explores the data exchange roles of key stakeholders per building lifecycle stage. The third sub-question seeks to gain an understanding of the main challenges faced by key stakeholders regarding MP data exchange through the use of semi-structured interviews. This is followed by a case study which seeks to examine the TU Delft’s perspective as a public client and data owner regarding making data more accessible and interoperable for other stakeholders through the use of semi-structured interviews.

It is found that although ample data on materials and components exist, they are currently not accessible or interoperable for stakeholders across the sector. Stakeholders can be data providers or data extractors, however the responsibility for making data accessible and interoperable lies with the data owner who in most cases is the client. A lack of; standardised data, a government initiated centralised platform, data structure, and standards and norms are found to be the major challenges associated with data exchange of MPs. From a public client (TU Delft) perspective, it is found that although there is an understanding of improving data exchange, data privacy is a major hurdle that needs to be overcome before data can openly be shared with all stakeholders in the sector. In order to enforce a shift in the working methods of the building sector, more clients need to start demanding data from stakeholders.

The global imperative to embrace a circular economy, underscored by concerns over climate change, resource depletion, and urbanization, has spotlighted the need for sustainable practices and waste reduction, within the built environment. This master's thesis within the context of the circular economy delves into the challenges faced by the real estate sector, a substantial contributor to resource consumption and waste. The knowledge gap revolves around the financial feasibility of circular real estate development, especially for private equity real estate (PERE) investors. Despite acknowledging the environmental benefits of circular real estate, its construction methods often entail higher costs, creating a significant hurdle for real estate investors. In this context, there is limited financial justification for investing in circular real estate developments, particularly when focusing solely on financial outcomes. This study zeroes in on the logistics real estate sector in the Dutch market, exploring under what conditions there is a feasible business case for real estate investors to make a positive investment decision on circular real estate development. To address this problem, the research employs an action research methodology, combining theoretical insights with practical application. Two cycles of plan-act-observe-reflect guide the exploration, beginning with a focus group discussion with PERE investor practitioners. Subsequently, a case study of a circular logistics development opportunity is presented to an investment fund, allowing for a comparison of the business case against traditional development.

The research identifies nine interconnected conditions influencing the investment decision: cost, returns, timeline, market development, sustainability, strategic portfolio management, investor appetite, regulation, and tenant considerations. Importantly, certain conditions, such as cost, returns, investor appetite, market development, and strategic portfolio management, are highlighted as particularly critical in circular real estate, potentially exerting more influence than in traditional developments. The findings conclude the delicate balance between cost and returns, aligning investor expectations with long-term potential, strategically integrating circular projects into investment portfolios, and staying attuned to market dynamics as the most important conditions for circular logistics development.

This research contributes to closing the knowledge gap in the literature, providing valuable insights for real estate investors navigating the complexities of circular development. The identified conditions demonstrate transferability across diverse real estate sectors, validating their universal significance. Future research avenues include exploring different fund categories, extending the study across diverse real estate sectors, and investigating the complexities within investment funds related to sustainability. Additionally, examining ancillary benefits and refining cost increase estimates for circular construction can enhance financial feasibility insights. For practical implementation, establishing a dedicated sustainable impact fund and introducing regulations mandating material reuse are recommended. These insights aim to advance the discourse on sustainable real estate practices.

The concept of Circular Economy (CE) has emerged as a promising alternative to the current linear economy, decoupling economic activity from the depletion of natural resources and promoting a restorative and regenerative system. The transition of the building industry to a circular one can be achieved through four core resource principles: Narrow (minimising the use of primary resources), slow (extending the lifetime of buildings and products), close (regaining post-use and construction waste through reuse or recycling), and regenerate (minimising toxic substances and maximising the use of renewable resources). These principles provide a framework for exploring the role of digitalisation in the transition of social housing organisations (SHOs) toward circular housing practices, with a focus on European SHOs, particularly those in the Netherlands. This thesis follows a structured format comprising six chapters, with four of them encapsulating the author’s published articles. Chapter 1 serves as the introduction, providing a contextual foundation for the research. It outlines the overarching theme of the thesis, which revolves around the intersection of CE, digitalisation, and the built environment, with a specific focus on SHOs. The chapter sets the stage by identifying the gaps in existing literature, emphasising the need for a comprehensive conceptualisation of this emerging research field. It further delves into essential methodological aspects, the problem statement, and the broader significance of the research. In Chapter 2, the research delves into an exploration of the current state of CE implementation in Dutch SHOs and provides insights into the pressing barriers, and potential enablers. A Delphi study conducted with 21 social housing professionals reveals that, as of 2020, SHOs were in an experimental phase, incorporating circular construction techniques in pilot projects. Barriers encompass organisational priorities, operating within a linear system, and a lack of awareness. Also, financial challenges related to the costs of circular materials also emerge as significant hurdles. Chapter 3 develops a framework, the Circular Digital Built Environment Framework, in an exploratory qualitative research approach. This conceptual model integrates CE principles with digital technologies to provide an understanding of their potential applications within the built environment. The framework is constructed through expert workshops, literature reviews, and evaluations of current research and practices, resulting in the identification of over ten key digital technologies. These technologies encompass a broad spectrum, including big data analytics, blockchain technology, and material passports. The framework not only informs subsequent empirical studies but also serves as a valuable guide for scholars and industry practitioners navigating the intersection of digitalisation and circularity in the building industry. Chapter 4 presents an analysis of how enabling digital technologies, identified in Chapter 3, are practically employed in real-life practices, specifically within circular new build, renovation, maintenance, and demolition projects of forerunner Dutch SHOs. Employing a multiple-case study approach, the chapter gathers empirical evidence from three large-scale SHOs through semi-structured interviews, desk research, and extensive data analysis. The within-case and cross-case analyses reveal insights into the types of digital technologies being deployed, their impact on circular practices, and the challenges encountered in their adoption. By examining the real-world examples, Chapter 4 contributes to the evolving domain of digitalisation for a circular building industry. Chapter 5 addresses the challenges associated with data (identified in Chapter 4), with a specific focus on material passports as a crucial tool for circularity in existing housing stock. Employing a multiphase mixed-method research design, the chapter utilises the SCOPIS method (Supply Chain-Oriented Process to Identify Stakeholders) for user and data mapping. This approach results in a data template outlining the requirements of users for material passports. Subsequently, the study tests this template through a case study, identifying critical data gaps and proposing a material passports framework to address these gaps. By leveraging both digital technologies and human expertise, Chapter 5 offers solutions to enhance data management in the pursuit of circularity within the building industry. The findings contribute to ongoing industry and policy initiatives. Chapter 6, the concluding chapter, consolidates the exploration conducted throughout the thesis. It presents the overarching contributions of the research, offering a summary of the scientific and practice contributions and recommendations derived from the entire study.

Research on circular economy in the construction industry is only recently gaining momentum. A circular economy does not produce any waste. The construction sector is the most polluting sector in the Netherlands and uses 50% of the used raw materials. Therefore, circular building methods might decrease the demand on raw materials in the Dutch construction sector. This research aims to identify what factors can stimulate the adoption of circular building methods by the general contractor.

In this research a cross-case analysis is conducted with two building projects that aimed to use circular building methods. During the interviews for these case studies, some barriers for the adoption of circular building methods were identified. The six barriers which are mentioned most often are the perception of high costs, limited regulation, lack of a circular business model, unattractive esthetics, negative attitude from actors involved, and lack of integrality within the building process.

To have a positive influence on the adoption of circular building methods, and resolve the identified barriers, the general contractor may take the role of an integral manager to manage the social network, supply chain, and building process and facilitate the learning process. When taking this role it is suggested that the general contractor works together with other actors to develop a new business model. This new business model should aim to take away the current barriers for circular building methods.

The main difference between any other innovation in the building sector and circular building methods is that circularity needs more integrality. Other innovations are often only on a specific part of the project, it suffices with only changing or managing on a small part of a building project. However, circularity affects every small part of a project and therefore needs an integral manager.

In Chile, social condominiums are a significant part of the affordable owner-occupied housing stock. However, after decades of occupancy, this housing stock shows rapid signs of deterioration and devaluation due to neglected maintenance. This situation has evidenced a twofold challenge for low-income homeownership in Chile. On the one hand, it includes the financial and social restrictions faced by co-owners that diminish their collective capacity to take care of building maintenance. On the other hand, it includes institutional limitations with regard to housing management in terms of regulations, institutions and actors.
This research explores the intermediary role of the third sector in providing support, skills and building capacity among communities to improve the maintenance and administration of their properties. Based on international and local case study analyses, the research proposes a set of management approaches and strategies for Chilean third sector intermediaries to support low-income homeowners in condominium management. Findings show the relevance of multidimensional approaches and strategies, so as to tackle the interrelated challenges by contributing to enhance the community’s capacities and level the built environment conditions. Findings also show the need of partnerships between third sector organisations and municipalities to face complex areas, and the relevance of fostering collaboration and specialisation among third sector organisations.

In Ghana, public housing which is provided mainly for government employees plays an important role in socio-economic development. For instance, civil servants are more likely to accept transfers to areas where their services are most needed. Unfortunately, attention to public housing in Ghana has diminished over the years largely due to shift in policy focus towards the enablement approach. That is, private-sector-led housing production. The result is that, public housing conditions and quality continuous to deteriorate due largely to lack of maintenance. This is evident in many research and news publications, and the visible signs of deterioration such as leaking roofs, rotten ceilings, cracked walls, faded paint, and dysfunctional electrical and plumbing systems. Therefore, this thesis proposes an approach to management by local authorities that may bring about maintenance and lead to better conditions/quality of public housing. The approach proposes a defined structure with roles, responsibilities and relationships for the district assembly, the district coordinating director, the housing unit of the local authority, the works department, and tenants. It outlines a defined protocol for addressing repairs and maintenance including mechanisms to receive and respond to everyday repairs from tenants. Furthermore, it proposes that district assemblies should be fully responsible for determining and collecting rents so as to ensure reliable and secure finance for maintenance. It recommends the participation of tenants in management through mechanisms such as regular meetings or tenant representatives. Finally, it recommends mechanisms such as planning, budgeting, and submission of annual accounts to monitor and ensure that rents are spent on maintenance.

This book is about work floor experiences of professionals at work floors of housing organizations in The Netherlands in their attempts to apply supply chain partnering. I did not only choose this topic because of its academic and practical relevance. The choices I made, and the personal motivation behind those choices say a lot about what has driven me to do this research. Therefore, this prologue focusses on the experiences that have led me to conducting this PhD-research. In answering this question, I will describe a few milestones that I consider important events that led me towards this research.

Central to this PhD research was the problem of the lack of aff ordable housing for young starters in Malaysia. The solutions for aff ordable housing that are available in the market do not truly solve the problem from the customer’s point of view. Hence, it was important to analyse the contributing factors associated with the term ‘aff ordability’. The term touches upon interconnected elements that cover many issues ranging from demand (housing needs, demographics, household income, quality housing) to supply (the authorities’ requirements, design, cost, sustainability and procurement). In this thesis, we discuss some of the problems related to the supply and demand issues and examine a possible intervention to solve the problem.
This research contributed to the body of knowledge by employing a prescriptive strategy and designing an innovative fl exZhouse business model (BM), and by applying an in-depth strategy that revealed why the problem exists and why there is still no appropriate solution. The result provides a description of the situation that young starters fi nd themselves in, the reactions of the industry’s key players and the policies that hamper innovation in the housing market.