From Fragmentation to Collective Action: A System Dynamics–Based Approach to Addressing Stakeholder Engagement in the Building Sector’s Circular Economy Transition ^†

Abstract

The building sector holds significant potential to mitigate climate change by adopting the circular economy. However, its transition is impeded by fragmented stakeholder engagement arising from complex socio-organisational dynamics. To address this, this article adopted the system dynamics (SD) modelling tool, which enables structured visualisation of the system while exploring and assessing stakeholder dynamics. The three-stage methodological approach includes the following: problem identification, building on the author’s prior publication, which identified the variables and their direct relationships; system conceptualisation, where the causal loop diagram was developed, followed by the identification of feedback loops, construction of the stock-flow diagram, and ultimately the SD model to capture indirect relationships; and model optimisation, which calibrated the SD model based on real-world circular building scenarios. The results revealed the stakeholder dynamics through their associated concerns. The results indicated that leveraging stakeholder dynamics within the complex system could foster collective action from fragmentation to enable the effective circular economy transition. This article proposes general and phase-specific actions tailored to each stakeholder, offering a structured framework for coordinated decision-making. These actions help bridge the gap between theory and practice, facilitating the sector’s transition from its current linear model toward a more collaborative and circular approach to climate change mitigation.

1. Introduction

Climate change continues to impact human well-being and ecological stability, driving alterations in atmospheric and oceanic temperatures, disrupting precipitation patterns, accelerating sea level rise and heightening the incidence of high-impact weather events [1]. Various mitigation and adaptation strategies have been implemented at national and international scales to address climate change, with the Paris Agreement widely regarded as a landmark accord, setting a target to keep global temperature increases well below 2 °C, preferably under 1.5 °C [2]. However, there is still a long and challenging path to attain them. The way to combat climate change is through reducing global greenhouse gas emissions, and thus achieving decarbonisation [3].

Given that the building sector is estimated to contribute about 40% of global resource consumption, 30% of energy use, and 37% of greenhouse gas emissions, it is increasingly recognised as an influential force in efforts to achieve the Paris Agreement’s decarbonisation goals [4,5]. As a result, a complex and reciprocal environmental relationship characterises the link between the building sector and climate change, reflecting their mutual and significant influence [6].

Addressing the link between climate change and the building sector necessitates a comprehensive, life-cycle-oriented systems approach, as fragmented efforts continue to undermine coordinated decarbonisation strategies [5]. Involving stakeholders within the building life cycle is crucial for gaining commitment and implementing effective mitigation and adaptation measures. Within this framework, the circular economy presents a compelling solution to the sector’s environmental challenges [7]. It calls for a systemic shift in the global economic paradigm and operational practices, offering new ways to redefine the sector’s role in climate action [8,9].

According to the Ellen MacArthur Foundation, the circular economy is a regenerative and restorative model focused on extending the life and value of materials, products, and components through their entire life cycle [8]. Although the concept has gained significant global traction, scholars have pointed out limitations, including insufficient integration of social aspects, unclear sustainability outcomes, and an overemphasis on technological interventions [10,11]. These critiques do not refute the value of the circular economy; instead, a more holistic and inclusive application is encouraged [12].

The circular economy offers considerable environmental advantages in the building sector, such as reducing reliance on natural resources, minimising waste from construction and demolition, and lowering greenhouse gas emissions [13]. Beyond them, it also delivers substantial social and economic advantages, including job creation, the reinforcement of local supply chains, and increased community resilience [14].

Efforts to embed the circular economy are gradually reflected in policy reforms, regulatory instruments, and incentive mechanisms, encouraging new business models and strategic practices in the building sector [15]. Core strategies promoted in this context include valorising construction and demolition waste, designing buildings for reversibility, and fostering collaboration among diverse stakeholders throughout the value chain [16,17]. Despite growing interest, the sector’s adoption of the circular economy remains inconsistent and fragmented, with multiple barriers limiting effective implementation [18,19].

Active stakeholder involvement is essential to facing these barriers and fostering smooth engagement across the building life cycle [20]. However, the building sector’s conservative social dynamics foster complex organisational dynamics, leading to fragmented stakeholder engagement [21]. The absence of effective stakeholder engagement leads stakeholders to work in isolation, forming so-called communication silos, focusing solely on time, cost, and quality, and thus hindering the adoption of sustainable practices and reinforcing a short-term perspective to meet regulatory requirements rather than embracing innovative and long-term sustainability perspective [20,22].

The building sector is inherently complex and often marked by fragmented stakeholder engagement, entangling the circular economy within this complexity [23]. Consequently, the decision-making about the circular economy in this sector remains disjointed and immersed in complexity. This complexity arises from the numerous interconnected variables and their dynamic interactions, particularly in relation to climate change. The system exhibits what is known as dynamic complexity, where the evolving interactions between variables over time lead to unpredictable and counterintuitive outcomes [24]. To navigate this complexity and support a more coherent transition, adopting the systems thinking approach becomes crucial for identifying interconnections and enhancing decision-making [25].

While systems thinking has proven valuable in addressing the complexities of circular economy transitions [26,27,28], there remains a lack of focused analysis on stakeholder dynamics within the building sector [24,25]. This article addresses this gap by employing the systems thinking perspective to explore, assess, and visualise stakeholder dynamics for a more effective circular economy transition. It builds upon the author’s prior publication [23], which introduced the early stages of system dynamics (SD) modelling, including problem articulation and formulation of dynamic hypothesis, only through a stakeholder-linked causal loop diagram. This article, instead, expands this foundation by completing the SD model, integrating real-world circular building scenarios, and translating stakeholder concerns into general and phase-specific actions. It thus offers a novel, stakeholder-centric modelling framework that supports coordinated decision-making, aiming to shift the building sector from a fragmented, linear model toward a more collaborative and circular approach to climate change mitigation.

Beginning with the interconnection between climate change and the building sector, the introduction section positions the circular economy as a vital climate mitigation strategy while highlighting the systemic complexity that challenges its implementation (Section 1). The state-of-the-art section introduces a systems thinking framework, emphasising stakeholder dynamics within the complex system where the building sector, circular economy, and climate change converge (Section 2). The methodology section outlines the SD as a simulation tool to explore these dynamics (Section 3). The results and discussion section presents and analyses the model outcomes (Section 4). The conclusions section concludes this article with reflections on the results and their implications (Section 5).

2. State of the Art

As complexity within systems increases, it has become evident that conventional approaches have often failed to resolve persistent challenges and, in some cases, may have unintentionally contributed to them [25]. To mitigate this, the systems thinking approach emphasises viewing the world through the lens of complexity, recognising that all elements are interconnected [25]. According to Richardson (1991) [29], the systems thinking approach enables a deeper understanding of complexity, supports the development of more effective policies, and facilitates meaningful change while promoting faster learning, identifying high-leverage intervention points, reducing unintended consequences, and encouraging decision-making aligned with long-term goals.

Embracing the systems thinking approach is fundamental to advancing the circular economy, as it highlights the interconnected nature of socio-economic and environmental systems [30,31]. For effectively guiding the decision-making in the circular economy transition, its principles must be translated into practical, actionable frameworks [32]. This calls for transcending traditional disciplinary boundaries [33] and moving from optimising individual components to enhancing entire systems [8]. Additionally, the complexity of this transition necessitates the use of advanced tools that can handle uncertainty, model dynamic interactions, and anticipate potential future developments [34,35].

Informed decision-making, as a cornerstone of the circular economy transition, remains deeply embedded in complexity, further exacerbated by the lack of adequate tools to capture the dynamic behaviours of systems and the absence of process-based frameworks to guide the transition [24]. Pieroni et al. (2019) [36] highlight that many existing circular innovation tools, such as those derived from industrial ecology, tend to offer only static representations, depicting the system as a snapshot at a single point in time. While industrial ecology approaches help to evaluate sustainability potential, they fail to capture market dynamics and supply chain efficiencies due to their inherent disregard for temporal factors. Moreover, these tools often emphasise technological systems while overlooking the social dimensions embedded in socio-technical networks [37,38]. As a result, they are insufficient for modelling the dynamic nature of complex systems [39]. This gap has led to a growing interest in simulation tools rooted in complex systems science, which are more capable of reflecting time-based system evolution and the interplay between technological and social networks. These tools are particularly relevant for the building sector, where multiple stakeholders with varying goals are interconnected across the building life cycle. Therefore, addressing the circular economy transition requires tools to effectively model these interactions over time and across networks to support more informed and adaptive decision-making [37,38].

Complex System Science Simulation Methodological Tools

The existing scientific literature predominantly focuses on four key simulation tools rooted in complex systems science (

Table 1. Objective, scale of application, strengths, and limitations of the complex system science simulation tools [Source: Elaborated by the author, based on [37]].

Tool	Objective	Scale	Strengths	Limitations
SD	To explore how system structure shapes the behaviour of complex, evolving systems.	Macro- and Meso-Scale	Captures system-wide feedback loops; Represents market dynamics and social behaviours; Incorporates system parts and the whole; Allows for non-rational decision modelling; Time-dependent (dynamic); Integrates both quantitative and qualitative data; Highlights non-linearities, time delays, and stock accumulations.	May lack detailed representation of processes; Often data-intensive; Results can be hard to generalise; Limited environmental factor consideration; Challenges in capturing heterogeneities within stocks.
DES	To analyse the sequence of potentially stochastic events that drive system dynamics.	Micro-Scale	Provides detailed process-level modelling; Effectively captures event randomness; Time-dependent (dynamic); Suitable for analysing process flows and temporal variability.	Data-intensive; Limited to micro-scale; Does not incorporate feedback loops; Less effective for environmental and higher-scale systems.
ABM	To explore how interactions among heterogeneous agents influence overall system behaviour.	Micro- and Meso-Scale	Models heterogeneous agents; Captures emergent behaviours and local interactions; Allows for non-rational decision-making; Represents both individual and aggregate behaviours; Includes feedback loops; Time-dependent (dynamic); Avoids assumptions of homogeneity.	Highly data-intensive; Validation is challenging; Difficult to generalise; Model development complexity.
OR	To identify the optimal solution for structured decision-making problems.	Micro- and Meso-Scale	Enables optimal decision-making; Suitable for modelling cooperation and conflict scenarios (e.g., game theory); Uses multi-criteria decision-making (MCDM) for trade-offs across multiple criteria.	Computationally demanding; May not yield a solution or may produce infinitely many; Typically static and lacks system dynamics; Complex model development.

): system dynamics (SD), discrete-event simulation (DES), agent-based modelling (ABM), and operations research (OR).

These simulation tools grounded in complex systems science offer significant strengths and notable limitations. No single tool, however, can capture all the critical dimensions of the circular economy [37,38]. As a result, scientific literature increasingly advocates hybrid modelling approaches that integrate multiple methods to support more comprehensive sustainability assessments and informed decision-making in the circular economy transitions [40]. Among these tools, the SD has been especially recognised for enhancing systems thinking, particularly when analysing the circular transitions at the meso- and macro-scales [24]. It offers considerable potential for capturing systemic complexity and guiding decision-making. Nevertheless, the SD is often critiqued for the intricacy of its models and the demand for high-quality data [41]. However, these challenges can be addressed through rigorous sensitivity analysis and model calibration techniques [37,38].

This article addresses the complexity of the building sector’s circular economy transition by exploring, assessing, and visualising the stakeholder dynamics within the complex system where the building sector, circular economy, and climate change converge. This article employed the SD modelling tool, enabling structured visualisation of the system while exploring and assessing stakeholder dynamics. In conclusion, this article proposes general and phase-specific actions tailored to each stakeholder, offering a structured framework for coordinated decision-making. These actions help bridge the gap between theory and practice, facilitating the sector’s transition from its current linear model toward a more collaborative and circular approach to climate change mitigation.

The SD modelling tool was chosen because the methodological approach aimed to visualise the complex system at the building supply chain (meso-scale) in the whole building life cycle without any environmental impact assessment concerns. Additionally, the targeted variables were closely linked and influenced one another rather than functioning independently. As a result, the ABM was deemed unsuitable, either on its own or in combination with the SD, due to the meso-scale focus, life-cycle-wide scope, and the interdependent nature of the variables involved.

This article continues the author’s prior publication [23], in which the initial stages of the SD modelling process, encompassing the problem articulation and the formulation of the dynamic hypothesis stages, were addressed only through a stakeholder-linked causal loop diagram. A comprehensive critical literature review was used to identify the variables and their direct relationships. It then developed the causal loop diagram to derive their indirect relationships. However, the causal loop diagram included the stakeholders and their associated concern variables, although the stakeholders themselves could not be variables but only had a representative purpose in the system. Furthermore, it did not proceed with the feedback loop identification of the causal loop diagram, the stock-flow diagram, and the SD model construction, as they were the subsequent steps in the formulation of the dynamic hypothesis. Moreover, it did not proceed with the following four stages of SD modelling identified by [24], encompassing the formulation of simulation models, model testing, reliability testing, and scenario analysis, particularly when studying circular economy transitions [25].

In contrast, this article begins where the prior publication [23] concluded, using the data and insights generated as the foundation for advancing the SD modelling process. This article builds upon that groundwork by constructing the causal loop diagram based on the prior one, removing stakeholder variables, progressing to identifying feedback loops, developing the stock-flow diagram, and constructing and calibrating the SD model. Thus, this article extends the prior publication by advancing through an extended methodological approach to support a more comprehensive exploration, assessment, and visualisation of stakeholder dynamics.

3. Methodology

The working principles of the SD are based on the construction of the causal loop diagram to determine relationships between variables, thereby identifying balancing and reinforcing feedback loops. This is followed by the development of the stock-flow diagram based on the causal loop diagram [42]. Finally, the SD model is constructed using these diagrams and includes three variable types: stocks, flows, and auxiliary variables [43].

The existing scientific literature has widely explored the use of SD to address the complexity inherent in circular economy transitions by linking dynamic and interrelated system variables [26]. The SD has been used to model various scenarios that capture the evolving interactions within complex systems [27], serving as an effective tool for comprehensive system evaluation through iterative modelling techniques [44]. Applications of SD include analysing the impact of circular economy strategies at the firm level [41], integrating it with the ABM to examine behavioural shifts in circular innovation [45], and investigating product lifespans and consumer behaviour in the European electronics market [46]. It has also been applied to assess supply chain integration strategies, such as those related to iron ore consumption in the European steel industry [47], and to conceptualise the circular economy as a systemic transformation requiring coordinated actions across the macro-, meso-, and micro-scales [28]. The SD has been used in the building sector to model circular economy applications [48], particularly in waste prevention and management [49]. These studies highlight the SD’s versatility and potential to support decision-making in circular economy transitions across various scales.

The SD modelling tool operates through an iterative process of model creation, validation, and scenario analysis [50], specifically scope selection, dynamic hypothesis generation, causal loop diagramming, quantification, reliability testing, and scenario analysis [25,51]. Guzzo et al. (2022) [24] propose a five-stage SD modelling and simulation framework comprising problem articulation, formulation of the dynamic hypothesis, formulation of simulation model, model testing, and policy design and evaluation, especially suited for circular economy transitions.

This article adopted a three-stage approach based on [24,25] following stages: problem identification, system conceptualisation, and model optimisation. As noted in (Section 2), this article and the prior publication [23] are derived from the author’s Ph.D. thesis and represent two phases of a continuous research process. The problem identification stage was initiated in the author’s prior publication [23], where the variables as the stakeholders, their associated concerns, and their direct relationships were first identified. These variables were derived through a comprehensive critical literature review of scientific and non-scientific documents relevant to the building sector’s circular economy transition in the European context. This article builds directly on that foundation by integrating those results and advancing the modelling process through the remaining stages. The system conceptualisation stage formulated the dynamic hypothesis to determine the indirect relationships among variables. This stage included four steps: causal loop diagram construction, feedback loop identification, stock-flow diagram construction, and SD model construction. The causal loop diagram was first constructed based on the prior model [23] and refined by excluding stakeholder variables as they are not directly modelled in the SD modelling process. This was followed by identifying reinforcing and balancing loops and developing the stock-flow diagram that provided the foundation for the SD model. The model optimisation stage calibrated the SD model using real-world circular building scenarios. This stage included two steps: real circular building scenario model construction and optimised SD model construction. Eleven real-world circular building case studies were selected from the scientific and non-scientific literature [52,53,54,55,56] based on the availability and accessibility of documentation. From these case studies, circular economy variables were extracted and systematised. These variables were used to construct the real circular building scenario model and integrated into the original SD model to extend and calibrate it. The integration process involved mapping the extracted circular economy variables onto the relevant sections of the existing SD model. This was achieved by aligning each variable with the system components previously identified through stakeholder concerns. Optimisation in this context refers to refining the conceptual SD model by enhancing its practical relevance while ensuring that real-world strategies and design interventions from circular building case studies are structurally embedded into the model to improve its completeness and applicability. Since the selected circular building case studies also originate from European contexts, the model reflects conditions typical of European practice; however, its structure is adaptable to other national or regional contexts by including or substituting locally specific variables.

The optimised SD model was developed as a conceptual and structural representation rather than a fully quantified simulation model. While the relationships between variables were visualised and mapped, mathematical equations were not formulated due to the input data’s heterogeneous and largely qualitative nature. As such, the model supports the interpretation of stakeholder dynamics rather than computational simulation. All modelling work was conducted using Vensim^® PLE (Version 10.1.0) software, which was selected for its computing capabilities and flexibility in visualising complex systems.

As no primary data were collected and the model was not simulated mathematically, validation was instead approached through conceptual and structural consistency. The model was refined during development to ensure that the structure, feedback loops, and variable relationships aligned with insights from the scientific and non-scientific documents’ real-world circular building case studies. Although no formal expert validation or simulation-based testing was conducted, integrating variables from documented European circular building case studies aligned the model with established patterns of circular economy transition. This structural consistency enhances the model’s credibility within its intended conceptual scope.

4. Results and Discussion

4.1. Problem Identification

The problem identification was the first stage of the SD modelling process, aiming to define the system’s boundaries and narrow the focus to a specific issue rather than attempting to visualise the system [25]. This stage was elaborated with a whole life cycle perspective, building upon the authors’ prior publication [23] and adopting data already identified through a comprehensive critical literature review, which mapped the stakeholders along with their roles, objectives, and concerns. However, only the internal stakeholders were considered, excluding external stakeholders, banks, and financial institutions, to simplify the intrinsic complexity of the dynamic system.

The identified stakeholders and their associated concerns [23] were as follows:

• Owners and users/consumers were primarily concerned with well-being and comfort, and economic feasibility.
• Project managers, designers, architects, and engineers shared a focus on the creative and effective application of technologies, as well as cost efficiency.
• Facility managers were concerned with the creative and effective application of technologies, cost efficiency, and economic feasibility.
• Contractors, subcontractors, construction companies, suppliers, and manufacturers highlighted concerns about natural resource supply, economic feasibility, cost efficiency, and workforce.
• Real estate agencies prioritised economic feasibility.
• Demolition and deconstruction companies, and waste treatment companies focused on economic feasibility, cost efficiency, and workforce.

The stakeholder’s associated concerns were initially defined and classified into five main categories: social, organisational, economic, technical and technological, and environmental issues [23]. These were as follows:

• Social issues included well-being and comfort, referring to stakeholders’ emotional, physical, and psychological state.
• Organisational issues were represented by the workforce, referring to all project professionals directly participating in the building life cycle, including contractors, subcontractors, architects, engineers, project managers, demolition and deconstruction companies, and waste treatment companies.
• Economic issues encompassed economic feasibility, defined as the degree to which benefits outweigh costs and cost efficiency, related to optimising financial performance through improved processes.
• Technical and technological issues included creative and effective application of technologies, referring to the innovative use of technological solutions and natural resource supplying concerning the provision of energy, water, raw materials, and minerals.
• Environmental issues were represented by environmental protection and impact reduction, defined as actions aimed at safeguarding the environment and minimising negative ecological impacts.

Thanks to the identified stakeholders and their associated concerns within the building life cycle, direct relationships between them were obtained [23]. The results indicated that stakeholders prioritise social, organisational, economic, technical and technological issues, often overlooking environmental ones. Thus, stakeholders’ decisions are limited to integrating sustainability and circular economy, contributing to reducing environmental impacts and mitigating climate change [32]. This can be attributed to the inherent complexity of stakeholder dynamics and their fragmented engagement [24], where they operate in isolation, focusing on their immediate responsibilities without understanding each other’s roles and awareness of their collective environmental impact, leading them to a compliance-based approach rather than proactive engagement with sustainability [32,57]. Nonetheless, the results highlighted that certain concerns are shared across stakeholders, revealing the potential for indirect relationships while offering opportunities for establishing collaborative and communicative ties and enabling a shift from fragmented stakeholder engagement across the building life cycle [38].

4.2. System Conceptualisation

The system conceptualisation was the second stage of the SD modelling process, aiming to develop the “dynamic hypothesis” to conceptualise the system. This stage was intended to interpret the behaviour of the defined problem through the lens of feedback mechanisms and the stock-flow framework within the model [41].

This stage was elaborated to determine the indirect relationships between variables. The causal loop diagram was constructed based on the prior model [23], removing stakeholder variables. Then, the feedback loops were identified, progressing with the construction of the stock-flow diagram and the SD model successively.

4.2.1. Causal Loop Diagram Construction

The prior causal loop diagram [23] was constructed through a structured methodological approach. Initially, stakeholders and their associated concerns were defined as variables, with their direct relationships illustrated through directional arrows within the system model. The causal loop diagram was developed using a colour-coded visual scheme, where stakeholder variables were represented in blue and concern variables in black. Arrows were used to visualise relationships: black arrows indicated direct relationships between stakeholders and their associated concerns, while blue arrows illustrated relationships among concern variables. A positive relationship between variables is indicated by a plus sign (+), while a negative relationship between variables is indicated by a minus sign (−). Furthermore, predecessor and successor factors were introduced to better capture the internal dynamics between concerns regarding how they influence or are influenced by others.

Thanks to the prior causal loop diagram, indirect relationships between stakeholders and their associated concerns were obtained [23]. Although the stakeholders’ associated concerns were quantitative and qualitative data that could be utilised in the SD modelling, the stakeholders themselves were not. In other words, the stakeholders themselves could not be variables but only had a representative purpose in the system. Therefore, the causal loop diagram (Figure 1) was constructed in this article, exclusively using the concern variables, with stakeholders excluded.

The relationships between variables are not limited to simple one-way interactions; instead, they can influence one another in cyclical patterns known as feedback loops. These loops occur when variables mutually affect each other, either by reinforcing or balancing the effects within the system. A reinforcing loop is formed if the variables affect each other positively, leading to continuous growth or escalation. In contrast, a balancing loop emerges if one negative relationship between them balances the loop.

4.2.2. Feedback Loop Identification

In the causal loop diagram (Figure 1), only one reinforcing loop, R1, was identified. The R1-reinforcing loop (Figure 2) demonstrates a dynamic cycle within organisations, emphasising the interaction between workforce capabilities, economic feasibility, and the innovative use of technologies.

These variables reinforce one another, creating a cycle of continuous enhancements and sustained organisational development. Investing in workforce training enhances employees’ ability to apply technologies effectively, resulting in improved productivity and reduced operational costs [58]. These gains contribute to greater economic feasibility, enabling reinvestment in advanced technologies and further workforce development [59]. Organisations can adopt more sophisticated technologies as financial performance improves, boosting innovation and productivity [60]. This cyclical reinforcement sustains long-term competitiveness in a rapidly evolving building sector. The R1-reinforcing loop could be vital in the building sector’s circular economy transition since it encourages sustainable practices, improves resource efficiency, and drives ongoing innovation.

4.2.3. Stock-Flow Diagram Construction

The stock-flow diagram was constructed on the foundation of the causal loop diagram (Figure 1) through the assessment of cumulative behaviour and the number of interconnections with other variables. Cumulative behaviour was assessed to identify stock variables through outflows and inflows. According to these criteria, the variable “Workforce” exhibited the highest accumulation level and interrelationships; thus, it was selected as the primary stock variable. Additionally, “Environmental Protection and Impact Reduction” and “Creative and Effective Application of Technologies” were identified as stock variables due to their cumulative behaviour, extensive interrelationships, and relevance to circular economy strategies and environmental impacts. Their inclusion aimed to reflect the system’s holistic influence on the SD model.

These considerations led to the development of the stock-flow diagram (Figure 3). It was developed using a colour-coded visual scheme, similar to the diagrams that had been constructed previously.

The results have been presented for each stakeholder. Even though the stakeholder variables were not present in the diagram, the results were obtained following their direct relationships with their associated concerns, and the shortest path between the concern variables was successively considered.

The results indicated that effective collaboration and communication between owners and contractors is essential for managing various aspects. The reciprocal relationship between owners and contractors emphasises their interdependence, as owners rely on contractors to execute decisions related to workforce dynamics and natural resource supply, while contractors provide valuable insights on practical limitations [61]. The notable influence they can exert on the workforce members whose needs and financial decisions influence owners through the economic feasibility of building processes and operations. The correlation between natural resource management and owners’ decisions shows how they indirectly shape environmental mitigation measures [14]. Collaboration with workforce members is also crucial in owners’ economic, technical and technological, and environmental decisions. Their strategic decisions influence cost efficiency and determine how technologies are applied, with creativity and effectiveness in implementation feeding back into owners’ decisions [62]. Moreover, owners also significantly affect how workforce members implement environmental strategies, highlighting owners’ responsibility in driving environmental impact reduction. Their proactive role in advocating sustainable practices, especially in the design, construction, and use phases, underscores their importance in the building sector’s circular economy transition to mitigate environmental impact and combat climate change.

The results indicated that users/consumers are significantly influenced by well-being and comfort in their decisions. This aspect is closely linked to collaboration and communication with owners, whose decisions directly impact their satisfaction. Contractors and workforce members also play a key role in how they experience building operations through the creative and effective application of technologies [63]. Furthermore, their well-being and comfort are also improved by associating the actions and considerations to reduce the environmental impacts, promoting healthier and more sustainable living spaces [64]. Economic feasibility is another key driver of user/consumer decisions, in which the workforce members’ financial decisions can impact them, ensuring their well-being and comfort. Users’/consumers’ focus on well-being and comfort is also tied to sustainable natural resource management, linking environmental conservation with improved living conditions. Efficient and innovative technology applications supported by workforce members’ decisions enhance economic feasibility, benefiting the users/consumers through increasing well-being and comfort and reducing costs [36]. However, users/consumers have limited direct influence over cost efficiency. Their influence is mainly restricted to the use phase, yet they can still contribute to the circular economy by demanding sustainable solutions and influencing practices that reduce environmental impact and support climate change mitigation in the building sector.

The results indicated that workforce members’ decisions are oriented around multiple issues, creating strong interconnections within building processes and operations. They are encouraged to adopt innovative technologies that enhance productivity, efficiency, and sustainability while prioritising economic feasibility [65]. The interdependence between cost efficiency and the workforce members also drives efforts to optimise expenditures. Additionally, their active involvement in applying advanced technologies reduces resource consumption and contributes to environmental impact reduction actions [66]. Their role in resource management and technological innovation highlights their contribution to fostering environmental sustainability strategies. They also ensure well-being and comfort by implementing cost-effective, eco-friendly measures, contributing to sustainable environments [48]. Workforce members are essential in promoting the building sector’s circular economy transition, especially during the construction and use phases, where their decisions significantly affect economic and environmental sustainability. By prioritising the circular economy through efficient natural resource use and adopting eco-friendly technologies, they can substantially reduce environmental impact and play a key role in addressing climate change.

The results indicated that facility managers play a pivotal role in advancing sustainability through the creative and effective application of technologies to reduce environmental impacts. Their technological decisions, focused on minimising natural resource consumption, directly enhance user/consumer well-being and comfort [67]. Additionally, facility managers significantly influence operational and organisational efficiency through their interactions with the workforce members, impacting economic feasibility, cost efficiency, and environmental sustainability strategies [14]. Moreover, their decisions are essential for balancing economic, environmental, and social considerations, emphasising the interconnected nature of their responsibilities in building management [68]. Furthermore, the reciprocal relationship between workforce members and economic decisions highlights the complexity of their role in achieving sustainable and efficient building operations. Facility managers are critical to the building sector’s effective circular economy transition, notably during the use phase, thus reducing environmental impacts and addressing climate change.

The results indicated that real estate agencies play a key role in shaping financial outcomes through workforce-driven technological decisions, underscoring the connection between economic feasibility and innovation. However, their influence on broader issues, such as cost efficiency, user/consumer well-being and comfort, environmental sustainability, and resource conservation, remains limited [69]. Real estate agencies must collaborate with other stakeholders to address these challenges [70]. This highlights a significant opportunity to drive sustainable change by integrating the circular economy, particularly during the use phase, where their impact is most pronounced, to reduce environmental impacts and mitigate climate change.

The results indicated that suppliers play a pivotal role in advancing sustainability, primarily thanks to their responsibility for managing the supply of natural resources. Economic feasibility is a key motivator for adopting innovative technologies, encouraging workforce members to apply these solutions creatively and efficiently to enhance productivity and reduce costs [71]. These financial drivers shape supplier strategies and influence product choices, promoting the pursuit of technologies that offer a competitive advantage. Moreover, suppliers are central to environmental impact reduction due to their control over resource consumption. Lowering reliance on natural resources can significantly reduce environmental harm and simultaneously improve user/consumer well-being and comfort [72]. However, achieving this often incurs higher costs, challenging balancing financial feasibility with sustainability objectives. By embracing advanced technologies, fostering collaboration with stakeholders, and committing to environmentally responsible practices, suppliers can effectively reduce the environmental footprint of buildings and contribute to climate change mitigation and implementing the circular economy during the production phase.

The results indicated that manufacturers play a critical role in fostering the adoption of innovative technologies, which are also driven by economic feasibility. Financial considerations influence workforce members’ decisions, encouraging developing and using creative, efficient technological solutions that shape manufacturers’ strategic decisions. Integrating cost-effective innovations enhances manufacturing processes, operational efficiency, and overall performance [71]. Additionally, the supply of natural resources, managed by suppliers, directly impacts manufacturers’ environmental strategies. Reducing dependency on these resources supports sustainability goals and enhances user/consumer well-being and comfort, though often at the expense of cost efficiency [72]. This creates a complex challenge in balancing environmental priorities with financial viability to ensure the long-term sustainability of manufacturing operations. Manufacturers, therefore, hold a central position in advancing the building sector’s circular economy transition. Through advanced technologies, collaboration with stakeholders, and commitment to sustainable practices, manufacturers can significantly reduce the environmental impact of buildings and actively contribute to mitigating climate change during the production phase.

As the stock-flow diagram has represented the existing linear model of the building sector, the results identified the importance of each stakeholder’s role through their decisions in promoting the adoption of the circular economy toward environmental impact reduction and climate change mitigation.

4.2.4. System Dynamics Model Construction

The SD model was constructed by integrating two additional stock variables: “Environmental Impact Generation” and “Circular Economy Strategies”. This integration was essential to reflect the system’s complexity holistically. The author intentionally introduced these variables to conceptually represent the environmental outcomes of stakeholder actions and the utilisation of circular economy strategies to reduce those impacts across the building life cycle. This modelling decision aimed to enhance the model’s systemic completeness while supporting visualising the circular economy transition.

The new stock variable, “Circular Economy Strategies”, was connected via an inflow to the outflow of “Creative and Effective Application of Technologies” through a positive relationship. This reflects the idea that more creative and effective use of technology enhances the implementation of circular economy strategies. The other new stock variable, “Environmental Impact Generation”, was connected through an inflow to the outflow of the “Environmental Protection and Impact Reduction” via a negative relationship, indicating that increased protective actions reduce environmental impacts. To complete the system, the “Circular Economy Strategies” outflow was also connected to the inflow of “Environmental Impact Generation” with a negative relationship, signifying that a more significant application of circular economy strategies leads to decreased environmental impacts.

These considerations led to the development of the SD model (Figure 4). It was developed using a colour-coded visual scheme, similar to the diagrams that had been constructed previously.

The results from this model have been presented for each stakeholder, including only those insights that extend beyond the results already covered in the stock-flow diagram. As in the previous diagrams, the results were obtained by considering the shortest paths between concern variables based on the direct relationships with their corresponding stakeholder variables, even though the stakeholder variables were not explicitly included in the diagram.

The results indicated that owners, through collaboration with contractors, indirectly influence natural resource management, contributing to environmental impact reduction strategies [71]. Their engagement with the workforce members fosters the adoption of resource-efficient technologies, promoting circular economy strategies, which reduces environmental impacts [66]. Owners’ influence is crucial during the design, construction, and use phases, where their decisions shape long-term sustainability outcomes [67]. Thus, owners can contribute to the building sector’s effective circular economy transition to reduce environmental impacts and mitigate climate change while prioritising innovative solutions, maintaining collaboration, and balancing financial feasibility with environmental responsibility.

The results indicated that users/consumers, typically seen as passive participants, hold significant potential in implementing circular economy strategies, especially during the use phase [67]. Thus, they can be more proactive in promoting the circular economy effectively, leading to substantial reductions in environmental impacts and contributing to climate change mitigation when they are actively engaged.

The results indicated that workforce members’ ability to apply new technologies creatively supports the implementation of circular economy strategies, underscoring the interconnectedness between economic feasibility, technological advancement, and environmental sustainability [73]. Workforce members can effectively manage resource use and reduce consumption through innovative technological solutions while prioritising collaboration with other stakeholders [74]. This collaboration ensures that economic considerations align with environmental sustainability goals, paving the way for sustainability in all building life cycle phases. Thus, workforce members can contribute to the building sector’s effective circular economy transition to reduce environmental impacts and mitigate climate change through their commitment to cutting-edge technologies, resource efficiency, and active stakeholder communication.

The results indicated that facility managers are pivotal in advancing sustainability in the building sector by integrating circular economy strategies into their management practices. They can significantly reduce environmental impacts by optimising resource utilisation, minimising waste, and improving energy efficiency [68]. Their role extends beyond the use phase, with strategic interventions across the building life cycle, supporting the implementation of circular economy strategies while reducing reliance on natural resources and enhancing environmental sustainability efforts [14]. Thus, facility managers can contribute to the building sector’s effective circular economy transition to reduce environmental impacts and mitigate climate change while prioritising technological advancements and efficient resource management.

The results indicated that real estate agencies currently play a passive role in implementing circular economy strategies, primarily reacting to decisions made by owners, workforce members, and contractors. As intermediaries between owners and users/consumers, their influence on sustainability efforts is limited [69]. However, real estate agencies can contribute to driving the building sector’s effective circular economy transition to reduce environmental impacts and mitigate climate change by adopting a more proactive role in the use phase.

The results indicated that suppliers are key to sustainable resource management by reducing natural resource supply and consumption [71]. However, their influence on implementing circular economy strategies is restricted due to their limited impact on workforce-driven technological applications. Despite this, suppliers can reduce reliance on raw materials to improve user/consumer well-being and comfort, promote circular practices, and lead to lower environmental impacts while adopting circular economy strategies and economically feasible technologies [72]. However, suppliers must balance financial and environmental goals to ensure long-term sustainability, as these efforts may involve higher costs. Thus, suppliers can contribute to the building sector’s effective circular economy transition to reduce environmental impacts and mitigate climate change while adopting eco-friendly materials, reducing energy and water consumption, and minimising the use of new materials, thus taking a proactive role, particularly in the production phase.

The results indicated that manufacturers also play a crucial role in sustainable resource management in collaboration with suppliers; thus, they contribute significantly to sustainability [72]. However, manufacturers’ influence on implementing circular economy strategies is limited by their lack of control over workforce-driven technological innovations. However, manufacturers must balance economic and environmental goals like suppliers to implement the circular economy strategies [71]. Thus, manufacturers can contribute to the building sector’s effective circular economy transition to reduce environmental impacts and mitigate climate change while embracing innovative technologies, collaborating with stakeholders, and committing to sustainable practices, particularly in the production phase.

As the SD model has arrived at the representation of the circular economy transition from the existing linear model of the building sector, the results identified how the stakeholders could drive the implementation of the circular economy more effectively to contribute to environmental impact reduction and climate change mitigation.

4.3. Model Optimisation

The model optimisation was the third stage of the SD modelling process, aiming to optimise the SD model using real-world circular building scenarios. With this aim, circular building case studies were selected from the scientific and non-scientific literature. From these case studies, circular economy variables were extracted and systematised. These variables were used to construct the real circular building scenario model. Finally, the SD model has been optimised thanks to their integration.

4.3.1. Real Circular Building Scenario Model Construction

The real circular building scenario model was constructed based on the circular economy variables determined based on the circular building case studies, which were as follows:

• The Green House (The Netherlands);
• The Venlo City Hall (The Netherlands);
• Biological House (Denmark);
• Temporary District Court (The Netherlands);
• The Upcycle House (Denmark);
• The Green Solution House (Denmark);
• The Enterprise Center (UK);
• Rathaus Korbach (Germany);
• The Brummen Town Hall (The Netherlands);
• The Liander Head Office (The Netherlands);
• The Resource Rows (Denmark).

These eleven circular building case studies were selected based on the availability and accessibility of detailed scientific and non-scientific documentation [52,53,54,55,56]. A structured qualitative content analysis was conducted to identify recurring variables related to circular economy strategies, stakeholder roles, and system-level performance outcomes. Key themes such as natural resource use, material reuse potential, energy efficiency, and information accessibility were coded across case studies. These results were then standardised and grouped into seven variables used in the model optimisation phase. This process ensured consistency in translating diverse case study insights into a unified SD model. The identified circular economy variables were as follows:

• “Natural Resource Utilisation Minimisation” referred to minimising natural resource utilisation.
• “Raw Material Selection” was attributed to carefully selecting raw materials while considering them as low-impactful as possible to the environment.
• “Energy Efficiency” considered the less energy consumption to perform the same task.
• “Information Availability and Accessibility” meant the easy accessibility and free availability of information through stakeholder collaboration and digital technology utilisation.
• “Waste Reduction” referred to reducing waste production.
• “Reutilisation and Recycling Potential” focused on ensuring the building itself, with its materials and components, a second life through the circular economy principles and strategies such as reuse, recycling, and recovery.
• “Long-term Value” referred to capturing the asset’s long-term value, which can be the functional lifetime, aesthetic, well-being and comfort value, thanks to the circular economy principles and strategies.

While the identified circular economy variables were derived from real-world circular building case studies, they reflected practical objectives and operational focus areas rather than being directly mapped to a formal circular economy classification such as the 9R framework. This approach was chosen to align the model with how the circular economy aspects are currently framed and documented in sector-driven scenarios.

The interconnected relationship between the variables has been adopted according to the scientific and non-scientific literature documents [52,53,54,55,56]. The “Information Availability and Accessibility” was the model’s core, which directly and positively influenced all the other variables. The “Raw Material Selection” directly and positively impacted the “Natural Resource Utilisation Minimisation” and “Reutilisation and Recycling Potential”. As the “Natural Resource Utilisation Minimisation” was positively impacted thanks to the “Raw Material Selection” considering a low-impact approach to the environment, the “Energy Efficiency” and “Waste Reduction” were positively influenced, thus the “Minimised Impact on the Environment”. As the “Waste Reduction” increased through the minimised natural resource consumption, in turn, the “Energy Efficiency” was impacted positively, leading both of them to the increased “Minimised Impact on the Environment”. Finally, as the “Reutilisation and Recycling Potential” of the building itself and its materials and components increased, their “Long-term Value” also increased, leading both of them to the increased “Minimised Impact on the Environment”.

These considerations led to the development of the real circular building scenario model (Figure 5). It was developed using a colour-coded visual scheme, similar to the diagrams that had been constructed previously.

4.3.2. Optimised System Dynamics Model Construction

The optimised SD model was constructed by integrating the circular economy variables, thus the real circular building scenario model (Figure 5), into the SD model to transform it into a practical model from a solely theoretical model. The “Minimised Impact on the Environment” variable was excluded because the variable “Environmental Impact Generation” had the same function as the existing model.

The “Information Availability and Accessibility” was inserted into the system through the inflow of the stock variable “Creative and Effective Application of Technologies” because it is a common point of stakeholder collaboration and utilisation of digital technologies. The “Raw Material Selection” was integrated through a negative link to the “Natural Resource Supplying”. The reason was that as the raw materials are carefully selected and as low impactful as possible to the environment, that results in a decrease in the supply of natural resources, such as raw materials, energy, and water, into the building life cycle. The “Natural Resource Minimisation” and “Energy Efficiency” were inserted between the two stock variables of “Environmental Protection and Impact Reduction” and “Environmental Impact Generation” as being actions in the reduction in the environmental impact generation. Finally, the “Waste Reduction”, “Reutilisation and Recycling Potential”, and “Long-term Value” were implemented into the system between the two stock variables of “Circular Economy Strategies” and “Environmental Impact Generation” as a result of the application of the circular economy strategies leading to the reduction in the environmental impact generation.

These considerations led to the development of the optimised SD model (Figure 6) as the interconnected relationships between the variables of the real circular building scenario model have been placed. It was developed using a colour-coded visual scheme, similar to the diagrams that had been constructed previously. In this version, optimised concern variables were represented in red, and the relationships among these variables were illustrated using red arrows.

The results obtained have been presented for each stakeholder, including only those insights that extend beyond the results already covered in the SD model. As in the previous diagrams, the results were obtained by considering the shortest paths between concern variables based on the direct relationships with their corresponding stakeholder variables, even though the stakeholder variables were not explicitly included in the diagram.

The results indicated the crucial role of owners in environmental sustainability, mainly through collaboration with contractors and influence over natural resource management, further reducing waste and environmental impacts while supporting a coordinated approach to enhance overall performance [75]. Workforce members are also key in helping owners adopt innovative technologies and circular economy strategies, enabling material reuse, waste reduction, and greater long-term value [76]. Moreover, accessible and available information is key in supporting sustainable practices, while reliable data and expertise are essential for informed decisions and successful technology integration, emphasising the need for strong communication and knowledge-sharing within organisations [77]. However, owners face limitations in controlling raw material choices. Overall, owners are vital in guiding the building sector through the practical and effective circular economy transition toward environmental sustainability and climate change mitigation.

The results indicated a strong interconnection between users/consumers and various aspects of environmental sustainability, particularly in reducing environmental impact by lowering dependence on natural resources to support their well-being and comfort [78]. Furthermore, information availability and accessibility are key in guiding these decisions. In this regard, owners, contractors, and workforce members can support users/consumers in making environmentally sustainable and responsible decisions by providing relevant information, promoting efficient resource management, and encouraging technological adoption [79]. Collaboration among these stakeholders, knowledge sharing, and technology use are essential in shaping user/consumer decisions and advancing initiatives that enhance financial feasibility and satisfaction. However, users/consumers have limited influence on circular economy practices due to their passive role, which restricts participation in decisions related to material reuse, waste management, and long-term value creation [80]. Therefore, fostering a collaborative culture that encourages active user/consumer engagement is crucial. Despite their limited role, users/consumers can still significantly contribute to guiding the building sector toward the practical and effective circular economy transition, supporting broader environmental sustainability and climate change mitigation goals.

The results indicated the crucial role of workforce members in advancing technological innovation and economic feasibility. Their decisions are central to implementing circular economy strategies by enhancing reusability and recycling, reducing waste, and creating long-term value, further addressing environmental impacts [81]. Their decisions are strongly influenced by access to cutting-edge technologies and readily available knowledge. The availability of accurate and up-to-date information supports the effective integration of new technologies, enhancing both productivity and long-term sustainability [82]. Furthermore, workforce members contribute directly to reducing environmental impacts, promoting energy efficiency, and minimising resource consumption, thus reducing waste through efficient resource management and adopting innovative technologies. Their leadership in operational practices positions them as key actors in sustainability initiatives [83]. However, they have limited control over raw material selection. This limitation restricts their ability to influence sustainability holistically, as they can manage how resources are used but not which materials are selected at the outset. Overall, workforce members are vital in guiding the building sector through the practical and effective circular economy transition toward environmental sustainability and climate change mitigation.

The results indicated that facility managers are crucial in advancing environmental sustainability by implementing innovative technologies that reduce reliance on natural resources. They contribute to lowering environmental impacts through strategies such as improving energy efficiency and minimising resource consumption [68]. In this regard, their involvement is also central to the effective adoption of circular economy strategies. Utilising advanced technologies, facility managers can improve material reusability and recycling, reduce waste generation, and create lasting value within the building context. Moreover, accessible and reliable information shapes facility managers’ decisions. With access to up-to-date knowledge, they can effectively integrate advanced technologies into various building operations, improving economic feasibility [84]. However, facility managers have little influence over raw material selection. While they are instrumental in managing resource use during a building’s operation, their authority does not extend to material choices made at earlier stages. Overall, facility managers are vital in guiding the building sector through the practical and effective circular economy transition toward environmental sustainability and climate change mitigation.

The results indicated the importance of providing accessible and reliable information to support workforce members in informed decisions and the successful adoption of advanced technologies. This support is crucial for ensuring the economic feasibility of operations, particularly within real estate agencies [85]. However, a disconnect between real estate agencies and key environmental sustainability actions, such as energy efficiency and natural resource conservation, suggests a lack of emphasis on sustainability in their operational strategies [86]. Moreover, their role in promoting circular economy strategies remains limited. Their minimal involvement in material reuse, recycling, waste reduction, and long-term value creation reduces their impact on environmental performance [87]. Additionally, their restricted influence over raw material selection further constrains their ability to shape sustainable outcomes. Therefore, real estate agencies should enhance their engagement in sustainability initiatives, particularly in resource management, material selection, and implementing circular economy strategies. Despite their limitations, real estate agencies can still significantly contribute to guiding the building sector toward the practical and effective circular economy transition, supporting broader environmental sustainability and climate change mitigation goals.

The results indicated that suppliers contribute to environmental sustainability by managing natural resource supply chains, promoting energy efficiency, and reducing resource consumption, thereby lowering environmental impacts [88]. They also play a key role in waste reduction by optimising resource management during raw material selection, which influences manufacturers’ decisions based on availability, accessibility, and material quality [89]. However, suppliers have limited influence on implementing circular economy strategies, restricting opportunities for material reuse, recycling, and long-term value creation [90]. Despite this limitation, suppliers can still be vital in guiding the building sector through a practical and effective circular economy transition toward environmental sustainability and climate change mitigation.

The results indicated that the direct connection between manufacturers and workforce members significantly enhances the latter’s ability to acquire and apply technological knowledge. Prioritising information accessibility and availability helps both groups stay current with technological trends, improving operational efficiency and fostering a culture of innovation [91]. In addition, manufacturers play a critical role in promoting environmental sustainability by engaging with suppliers to ensure adequate natural resource management. Through this collaboration, they reduce environmental impacts by promoting energy efficiency and minimising resource consumption. Furthermore, accessible and reliable information supports manufacturers’ decisions regarding raw material selection. With access to relevant availability, quality, and sustainability data, manufacturers are better positioned to make informed, resource-efficient choices [92]. However, manufacturers still have limited influence on implementing circular economy strategies, which restricts the potential for material reuse, recycling, and long-term value creation. Despite this limitation, manufacturers can still be vital in guiding the building sector through a practical and effective circular economy transition toward environmental sustainability and climate change mitigation.

As the optimised SD model has arrived at the representation of the effective circularity transition in practices within the existing linear model of the building sector, the results identified how the stakeholders could achieve the practical, effective circular economy transition while transforming it from a sole theoretical concept to a practical concept.

4.4. Discussion

This article demonstrates the applicability and value of the SD modelling tool in exploring, assessing, and visualising the stakeholder dynamics within the complexity indorsed toward the building sector’s circular economy transition. It contributes to capturing the interdependencies and feedback mechanisms that shape decision-making across the building life cycle while addressing systemic fragmentation and the multidimensional nature of stakeholder interactions. While some studies promote the systems thinking approach in the circular economy transitions in the building sector [48,49,50,93], this article offers a stakeholder-centric model grounded in the literature and in practice. However, similar studies seeking to determine the objectives of this article and achieve comparable results could not be found in the existing literature. Therefore, these results could not be directly compared with other studies. Thus, this article offers a novel contribution, providing a comprehensive framework for identifying, conceptualising, and optimising the stakeholder dynamics through the SD, where traditional linear frameworks fall short. It further enhances its practical relevance by integrating variables from real-world circular building scenarios into the model while demonstrating the feasibility of system-wide transformation.

This article provides a conceptual foundation for more inclusive, informed, and effective circular economy implementation in the building sector. While interpreting the model outcomes, the author developed general and phase-specific actions derived directly from the stakeholder dynamics revealed through the SD modelling process. Thus, this article contributes a stakeholder-centric modelling framework that supports informed decision-making and introduces practical general and phase-specific actions tailored to each stakeholder (

Table 2. General and phase-specific actions [Source: Elaborated by the author].

Stakeholder	General Actions	Phase-Specific Actions
Owners	Establish clear sustainability goals with measurable benchmarks. Provide strong leadership and commitment to the circular economy. Foster collaboration and communication with stakeholders. Offer education and training on the circular economy to workforce members. Incorporate circular economy strategies. Adopt sustainable procurement practices. Implement monitoring and evaluation systems. Encourage innovation and experimentation. Celebrate successes and share best practices. Adapt and refine strategies based on ongoing assessment.	Design Phase: Request circular design for reversible buildings. Promote re-utilisation, recycling, and reduction in natural resource use. Collaborate with workforce members early to align on the circular economy goals.
		Construction Phase: Request the use of circular materials. Support the development of waste reduction strategies. Encourage on-site recycling.
		Use Phase: Implement energy-efficient technologies with facility managers. Conduct regular maintenance for extended lifespan. Align renovation/refurbishment with the circular economy principles.
		End-of-Life Phase: Develop deconstruction plans prioritising reuse and recycling. Maximise recovery of materials/components.
Users/Consumers	Establish clear circular economy goals and objectives. Integrate circularity into decisions. Collaborate with stakeholders. Invest in innovative materials and technologies. Prioritise sustainable procurement practices. Educate themselves and others about the circular economy. Monitor and measure the progress of the circular economy. Engage with the local community and stakeholders. Lead by example in their circular economy practices. Embrace continuous improvement and adaptability.	Use Phase: Adopt energy-efficient behaviours and appliances- Promote waste segregation, recycling, and composting. Prefer repair and refurbishment over disposal. Encourage resource sharing (tools, workspaces, amenities). Use sustainable transportation (bike, walk, carpool, public transit). Provide and support circular economy educational materials and workshops. Implement monitoring systems to track resource use. Purchase ethically sourced, durable, and recyclable products. Support circular business models. Collaborate with other users/consumers, owners, and facility managers to amplify the circular economy impact.
Workforce Members	Participate in practical education and certification programmes. Engage in hands-on pilot projects demonstrating circular economy strategies. Integrate circular design thinking with stakeholders. Foster collaboration with suppliers, manufacturers, and users/consumers. Manage circular supply chains and sourcing. Use data analytics to track and improve circular economy initiatives. Promote circular business models. Advocate for circular economy initiatives and participate in industry forums. Align circular economy initiatives with organisational sustainability goals. Manage risks and adapt strategies to changing conditions. Encourage continuous innovation through labs and forums. Ensure transparency by sharing progress and outcomes. Engage external stakeholders to build trust and scale impact.	Design Phase: Implement circular design principles. Use life cycle assessments to guide sustainable decisions. Collect data to track circular economy performance and refine strategies. Communicate and engage internally and externally for circular economy promotion.
		Construction Phase: Source disassemblable circular materials. Apply modular/prefabricated methods to reduce waste and resource use. Collect data to track circular economy performance and refine strategies. Communicate and engage internally and externally for circular economy promotion.
		Use Phase: Implement energy and water efficiency systems. Maintain durability and adaptability for repair/refurbishment. Conduct proactive maintenance routines. Collect data to track circular economy performance and refine strategies. Communicate and engage internally and externally for circular economy promotion.
		End-of-Life Phase: Prioritise deconstruction over demolition Collaborate with waste treatment for reuse/recycling. Collect data to track circular economy performance and refine strategies. Communicate and engage internally and externally for circular economy promotion.
Facility Managers	Undergo education and training. Establish clear sustainability goals and measurable targets. Provide leadership and assign accountability teams. Leverage BIM and other technologies for circular economy optimisation. Pilot and evaluate circular economy initiatives. Foster collaboration with owners, users, and other stakeholders. Conduct audits and track circular economy performance metrics. Publicly report on circular economy progress. Build a sustainability culture with recognition programmes. Adapt and iterate based on data and stakeholder feedback.	Use Phase: Install advanced energy management and efficient systems (HVAC, LED, smart thermostats). Conduct regular energy audits and implement improvements. Use low-flow fixtures, greywater systems, and rainwater harvesting. Promote native landscaping to reduce irrigation. Implement recycling and composting programmes with user education. Improve indoor air quality with ventilation, low-VOC materials, and non-toxic products. Support sustainable transport (bike racks, EV chargers, shuttle services). Monitor and visualise circular economy data (energy, water, waste) with dashboards. Report progress and recognise contributors to circular economy initiatives. Organise community-building events around circular economy practices.
Real Estate Agencies	Attend training sessions and courses. Establish clear circular economy goals and measurable targets. Assign leadership and accountability roles within the agency Use BIM and innovative materials to support the circular economy, Foster collaboration with stakeholders across the building life cycle. Develop and implement pilot projects for circular economy practices. Conduct regular audits and monitor circular economy performance metrics. Report publicly on progress to build transparency and trust. Encourage a sustainability culture with recognition and incentives. Continuously adapt strategies based on feedback and innovation.	Use Phase: Promote installation and optimisation of energy-efficient systems. Support facility managers in conducting regular energy audits. Encourage the use of water-saving fixtures and water-reuse systems. Promote native landscaping and rainwater management Support recycling and composting initiatives through education. Enhance indoor air quality through ventilation and low-VOC materials. Promote sustainable transport (bike racks, EV stations, shuttles). Implement dashboards to track energy, water, and waste performance. Report CE progress to stakeholders and adapt strategies accordingly Recognise and reward stakeholder contributions; foster community events.
Suppliers	Engage in education and training. Establish clear, measurable circular economy goals and targets. Adopt sustainable sourcing practices using renewable materials. Embrace circular product design (modularity, reusability, recyclability). Optimise resource use through efficient inventory and lean practices. Invest in innovative technologies (3D printing, AI, etc.). Implement material recovery and take-back programmes. Ensure traceability and transparency across the supply chain. Collaborate with manufacturers, workforce members, and public stakeholders. Monitor and report on circular economy progress regularly. Advocate for supportive policies and incentives. Continuously adapt and improve circular strategies.	Production Phase: Use certified sustainable raw materials. Implement circular product design principles. Apply lean manufacturing and digital inventory tools.
		Construction Phase: Provide modular, prefabricated, and recyclable materials. Promote on-site sorting and recycling in collaboration with the workforce members. Implement lifecycle tracking systems for materials.
		Use Phase: Provide maintenance and repair guidelines. Offer refurbishment and upgrade services. Track product performance and circularity with data.
		End-of-Life Phase: Run take-back programmes and partner with recyclers. Support deconstruction for material salvage. Monitor and report material recovery outcomes.
Manufacturers	Participate in education and training initiatives. Set sustainability goals for circular economy initiatives. Adopt circular product design principles (durability, reusability, recyclability). Conduct Life Cycle Assessments (LCA) to reduce environmental impact. Implement lean resource management and sustainable sourcing. Invest in emerging technologies (AI, IoT, blockchain, 3D printing). Operate material recovery programmes and take-back schemes. Ensure traceability and transparency in supply chains. Collaborate with suppliers, construction teams, and end users. Monitor KPIs on waste, resource use, and circularity. Report progress and barriers; iterate using data and feedback. Advocate for circular economy-aligned policies through stakeholder engagement.	Production Phase: Integrate circular design and sustainable sourcing practices, Use lean methods and digital tools to reduce waste, Implement material recovery and recycling systems.
		Construction Phase: Provide modular and prefabricated materials for easy reuse. Collaborate with the workforce members to minimise waste. Use digital tools (e.g., blockchain) for material traceability. Train site workers on circular economy strategies and practices.
		Use Phase: Design durable, repairable products and offer maintenance support. Use IoT to monitor product performance and predict maintenance. Educate users on proper usage and care to extend product life. Establish take-back systems for reuse and recycling.
		End-of-Life Phase: Collect and recycle products with dedicated systems. Partner with demolition and waste treatment companies. Gather data to improve future products and offer return incentives.

). The stakeholders are guided by these actions, which provide a strategic pathway toward the effective and practical implementation of the circular economy throughout the building life cycle. These actions equip stakeholders with tailored, actionable guidance, ensuring clarity on when and how to intervene most effectively in alignment with their roles and responsibilities. This lifecycle-based approach enhances their awareness of their influence within specific phases, empowering them to take targeted action aligned with their concerns and capacities. As a result, the cascading effects of fragmented stakeholder engagement begin to be reversed. Stakeholders shift from a compliance-driven mentality toward one centred on innovation, sustainability, and long-term focus. This transformation elevates their environmental awareness, fosters interdisciplinary understanding, and encourages shared ownership of sustainability outcomes. Consequently, communication silos are dismantled, cross-sectoral collaboration is enhanced, and the complexity of socio-organisational dynamics is more effectively addressed. Collectively, these outcomes support a more cohesive and impactful transition to circular economy practices in the building sector.

This article indicates that when approached through the systems thinking lens, stakeholder engagement can move beyond fragmentation to foster collective action, thus collaboration and communication to support the building sector’s effective circular economy transition. Thus, it offers practical implications for different stakeholders, providing a structured tool to inform stakeholder engagement, timing of interventions, and system-level strategy development. While the model remains conceptual, it lays a strong foundation for future simulation-based modelling and stakeholder-informed scenario testing.

5. Conclusions

This article indicates that while the building sector holds significant potential to contribute to climate change mitigation through adopting the circular economy, its transition is hindered by fragmented stakeholder engagement rooted in complex socio-organisational dynamics. The SD modelling tool was adopted in this article to systematically explore, assess, and visualise stakeholder dynamics within the complex system. The model was developed through a three-stage methodological approach: problem identification, system conceptualisation, and model optimisation. The problem identification stage, which was based on the author’s prior publication, identified the variables and their direct relationships. The system conceptualisation stage, where the causal loop diagram was developed, followed by the identification of feedback loops, the construction of the stock-flow diagram, and ultimately, the SD model, captured the indirect relationships. Finally, the model optimisation stage calibrated the SD model based on real-world circular building scenarios. The results revealed the critical role of stakeholder dynamics in shaping system behaviour and highlighted that, when strategically leveraged, these dynamics can support a transition from fragmentation toward coordinated collective action. In conclusion, this article proposes general and phase-specific actions tailored to each stakeholder, offering a structured framework for coordinated decision-making. These actions help bridge the gap between theory and practice, facilitating the sector’s transition from its current linear model toward a more collaborative and circular approach to climate change mitigation.

This article’s innovation stems from its focus on exploring, assessing, and visualising the stakeholder dynamics to guide the stakeholders thanks to practical general and phase-specific actions, summarising the steps to achieve the building sector’s circular economy transition. Furthermore, the methodological approach sets this article apart from existing literature. The systems thinking concept with the SD methodological tool is also a novel approach to addressing stakeholder dynamics, exploring, assessing, and visualising the complexity of the building sector’s circular economy transition. However, its limitations were based on the variable selection criteria bias. Moreover, the limitations have been set to reduce the complexity of the system’s dynamics, such as the exclusion of some stakeholders and their concerns. Additionally, the three-stage approach emerges as a limitation due to the lack of consideration of the formulation and execution of the final model, even though the model optimisation stage has been attempted to replace these stages. Furthermore, even though the complexity reduction within the system is aimed, the final model becomes complex to be holistically analysed. While the general and phase-specific actions aim to be practical and well aligned with stakeholder responsibilities and objectives, their feasible implementation may face challenges in practice due to regulatory readiness, organisational resources, and inter-institutional alignment. Further validation through expert review or field application would enhance confidence in their applicability. Furthermore, although these actions are directed at the European building sector, their practical applications could also be tailored to local regulatory, institutional, and cultural contexts in other countries or regions.

Future research should consider simulation-based testing of the model to evaluate dynamic behaviours under alternative scenarios. It could also focus on validating stakeholder actions through expert engagement or participatory modelling workshops. Applying the model in diverse geographic contexts beyond Europe would help to assess its transferability and support circular economy transitions in different built environment systems. This article, derived from the author’s Ph.D. thesis, provides a pathway for more resilient and sustainable climate action in the building sector through the practical and effective implementation of the circular economy while translating systemic complexity into structured knowledge.