Understanding barriers to circular economy design in mass timber construction: an innovation diffusion theory perspective Open Access

The construction industry is a major consumer of resources and a significant source of greenhouse gas emissions and waste production. The rising population, coupled with growing urbanisation and infrastructure demands, has further intensified construction activities. As the sector continues to grow, its environmental impacts worsen due to excessive resource extraction and waste disposal. This highlights the urgent need to reduce construction waste and improve the sector’s resource efficiency by adopting a circular production and consumption model (Mhatre et al., 2023; Munaro and Tavares, 2023; Pomponi and Moncaster, 2017). The circular economy (CE) is a regenerative industrial system that aims to create more value and economic opportunities by eliminating waste and maximising the useful life of materials for as long as possible (Askar et al., 2022; Ellen MacArthur Foundation, 2016; Cruz Rios et al., 2021). Kirchherr et al. (2017, P. 224) define CE as “an economic system that is based on business models which replace the “end-of-life” concept with reducing, alternatively reusing, recycling and recovering materials in production/distribution and consumption processes …”. By shifting from a “take-make-dispose” linear model to a restorative approach, CE minimises the need for virgin resources and redefines waste as a resource (Desing et al., 2020; Guerra and Leite, 2021).

While the CE concept has existed for decades, its adoption within the construction industry has seen limited uptake (Minunno et al., 2018; Osobajo et al., 2022). The sector remains the largest consumer of natural resources and continues to generate considerable amounts of waste and carbon emissions (Pomponi and Moncaster, 2017). For instance, in Australia, the sector was responsible for generating 38% of the country’s total waste in 2021. While the resource recovery rate has improved in recent years, most of these recoveries are limited to downcycling or energy recovery (DCCEEW, 2022). CO₂ emissions from this sector are still on the rise and are projected to double by 2050 (IEA, 2013). Transitioning to a CE model in construction requires a shift in design culture. Strategies such as design for disassembly, reuse, and adaptability must be integrated into design processes to retain building materials within a closed loop (Askar et al., 2022; Cruz Rios et al., 2021).

One key aspect of CE design is material selection. Materials suitable for CE applications exhibit properties such as durability, modularity, ease of disassembly, reuse, and recyclability (Ghobadi and Sepasgozar, 2023; Minunno et al., 2018). In addition, bio-based materials are especially favoured due to their reduced life cycle environmental impacts in terms of carbon footprint (Bertino et al., 2021; Dams et al., 2021). Mass timber exemplifies many of these desirable characteristics. As a durable, renewable, and bio-based material, it aligns closely with CE principles and offers a sustainable alternative to resource-intensive materials (Campbell, 2018). Life cycle assessment (LCA) studies show that timber outperforms concrete and steel in terms of reuse potential, material recovery, and carbon emissions (Duan et al., 2022; Liang et al., 2021; Puettmann et al., 2021; Sun et al., 2022). Emerging research also highlights mass timber's compatibility with CE design strategies such as design for disassembly and reuse, adaptability, and design for manufacture and assembly (DfMA), further reinforcing its suitability for CE applications in the built environment (Abad et al., 2024; Campbell, 2018; Ghobadi and Sepasgozar, 2023). When used in modular, prefabricated systems, mass timber construction (MTC) can also reduce material waste and enhance overall resource efficiency.

Despite these advantages, the adoption of CE design strategies within the MTC industry remains limited (Abad et al., 2024). In this context, the present study investigates the barriers that hinder the integration of CE strategies in MTC. To guide this analysis, the study employs Rogers' innovation diffusion theory (IDT), which focuses on the early stages of the innovation diffusion process that shape decisions to adopt or reject new practices. By applying this framework, the research aims to provide insights into the factors influencing the uptake of CE design strategies as an innovative practice within the MTC sector. The study focuses on CE strategies at the design stage due to their crucial impact on resource recovery during a building’s end-of-life (EOL) phase (Guerra and Leite, 2021).

Design plays a central role in achieving truly circular buildings. If buildings are not designed with circularity in mind, disassembly and reuse of their components at the building's EOL stage become difficult and inefficient (Cruz Rios et al., 2021). Circular buildings are defined as those “designed, planned, built, operated, maintained, and deconstructed in a manner consistent with CE principles” (Pomponi and Moncaster, 2017), and they function as material banks, where components can be reused after deconstruction (Benachio et al., 2020). Several CE design strategies have been proposed in the literature for application in the built environment, including design for disassembly, adaptability, durability, DfMA, material selection, use of secondary materials, and dematerialisation (Abad et al., 2024). CE design strategies aim to slow, close, or narrow the resource loop. Slowing the resource loop extends the use and reuse of products through durable design, reducing the need for new construction and raw material consumption (Bocken et al., 2016). Design for durability is an example of slowing the resource loop. Closing the loop refers to closing the material flow between post-use and production through recycling and reuse, while narrowing minimises the material and resources used per product (Bocken et al., 2016). Buildings designed for disassembly support both slowing and closing the loop by enabling component reuse. Using sustainable and bio-based materials, such as timber, in design is another example of closing the resource loop. Narrowing the loop is achieved through strategies such as dematerialisation or the use of secondary materials in design (Antonini et al., 2020). These strategies have been extensively discussed and defined in previous research (e.g. Abad et al., 2024), where readers can find detailed explanations.

Despite their crucial role in achieving a circular built environment, the implementation of these design strategies is still in its infancy (Guerra and Leite, 2021; Cruz Rios et al., 2021). In response, several recent studies have sought to identify barriers to the adoption of CE practices in the construction sector. Table 1 summarizes the most recent research in this area.

These barriers are commonly classified into cultural, economic, educational, technical, market, and regulatory categories. However, a review of the literature reveals that only a few studies explicitly focus on the factors influencing the adoption of CE design strategies (Akinade et al., 2020; Charef et al., 2021; Cruz Rios et al., 2021; Guerra and Leite, 2021; Kanters, 2020; Zaman et al., 2023). The majority of the literature takes a broader approach, examining various aspects of CE, such as its application in construction and demolition (C&D) waste management, supply chain dynamics, CE business models, and process management. The literature also highlights that the concept of CE in the construction industry is still not fully understood, with most adoption efforts concentrated on waste reduction (Zuofa et al., 2022). Given the critical role of design in achieving true circularity, a deeper understanding of CE design strategies and the factors influencing their successful adoption is essential.

Given the increasing demand for housing driven by rapid urbanisation, the construction sector must evolve to adopt more resilient, sustainable, and material-efficient systems. High-performance mass timber products, with robust structural capabilities and recognised environmental benefits, offer a promising alternative to conventional materials (Ahmed and Arocho, 2020).

Since the beginning of civilisation, wood has been a preferred building material due to its availability, strength, cost-effectiveness, and sustainability. To address the natural variability of wood and enhance its performance, engineered mass timber products have been developed. These products are designed to meet various engineering requirements, including strength, durability, and consistency (Ahmed and Arocho, 2020). Several innovative mass timber products are now available, including Cross-Laminated Timber (CLT), Glue-Laminated Timber (Glulam), Nail-Laminated Timber (NLT), and Dowel-Laminated Timber (DLT).

Despite its potential, systematic reviews have shown that the adoption of CE design strategies in the MTC sector remains limited (Abad et al., 2024; Ahn et al., 2022; Ghobadi and Sepasgozar, 2023). Design for disassembly has received some attention, primarily through proposals for novel connectors intended to facilitate deconstruction. However, these studies remain largely technocentric, focusing on material or component innovations (e.g. floor slabs) rather than systemic design integration or project-scale implementation (Dodoo et al., 2022; Derikvand and Fink, 2022). A few studies have also assessed the environmental benefits of design for disassembly, particularly in terms of CO₂ emission reduction and material recyclability (Al-Obaidy et al., 2022; Di Ruocco et al., 2023; Sun et al., 2022). For example, Di Ruocco et al. (2023) developed an LCA-based methodology to assess CO₂ emissions during the EOL phase of mass timber buildings, demonstrating that selective deconstruction and the reuse of timber components can result in net negative carbon emissions due to the material's carbon storage potential. However, practical implementation challenges are seldom addressed. The category of design for adaptability has seen even more limited application. Only one study by Dind et al. (2018) applied this CE design strategy by exploring the vertical extension of an existing mass timber office building. However, the study lacked a clear explanation of the design approach, underlying processes, and associated challenges. In relation to DfMA, several studies have explored composite CLT-steel modular systems, demonstrating their potential for low environmental impact and high structural efficiency (Loss and Davison, 2017; Loss et al., 2016). These findings are supported by LCA-based assessments that highlight their carbon reduction potential (Al-Najjar and Dodoo, 2022; Al-Obaidy et al., 2022). Further research into the practical application of this CE design strategy is required to understand challenges related to modularity and standardisation in MTC. Researchers investigating the CE design strategy of using secondary materials have primarily explored the practical possibilities of timber reuse. For instance, Llana et al. (2022) and Rose et al. (2018) experimentally tested hybrid CLT panels made from new and reclaimed timber, confirming their adequate mechanical performance. Similarly, Parigi (2021) explored the direct reuse of irregular mass timber elements via computational optimisation, demonstrating that reclaimed timber can achieve structural performance comparable to new materials. Finally, dematerialisation strategy has received limited attention, with studies mostly focused on reducing material use through panel or fastener optimisation (Al-Najjar and Dodoo, 2022; Dodoo et al., 2022; Loss and Davison, 2017).

Overall, the review reveals that research on the concept and application of CE design within MTC remains limited and largely at an early conceptual stage. The studies discussed above have addressed CE design strategies only indirectly and do not thoroughly examine or situate these strategies within a CE context. They also lack in-depth methodological detail and fail to consider the practical challenges associated with design, construction, and deconstruction processes. Moreover, no empirical research has investigated the factors influencing the adoption of CE design in MTC. The role of mass timber as both a circular material and a vehicle for advancing CE objectives through design has therefore been insufficiently explored. Without integrating CE design, mass timber continues to be framed narrowly as a low-carbon material. The successful diffusion of innovations such as CE design in the sector requires a clear understanding of the factors that impede their adoption (Suprun and Stewart, 2015).

This represents a significant knowledge gap, particularly given the increasing urgency to align construction practices with CE principles. This study addresses this gap through an empirical investigation of the barriers to adopting CE design in MTC, drawing on insights from experienced industry professionals to advance both theoretical understanding and practical implementation. Furthermore, no prior research has explicitly applied a theoretical framework to investigate these barriers in the construction sector. While some empirical studies have identified barriers based on expert opinion or case studies, they lack a guiding theoretical lens. To bridge this gap, the present study employs Rogers’ IDT as a novel framework for organising and interpreting the perceived barriers to the diffusion of CE design as an innovation in MTC construction.

Rogers' IDT is extensively used as a foundational framework for understanding the diffusion of innovation across various disciplines, including political science, education, communication, technology, and economics (Kaushalya et al., 2024). An innovation refers to any idea, product, or practice that is regarded as new by the members of a specific social group. It is irrelevant whether an idea is “objectively” new based on when it was first discovered or used; what matters is the individual’s perception of its novelty, which shapes their response to it. If an idea is perceived as new by an individual, it qualifies as an innovation. Diffusion is defined as “the process in which an innovation is communicated through certain channels over time among the members of a social system”, ultimately leading to social change as these innovations are adopted or rejected (Rogers, 2003).

The innovation-decision process occurs in five stages: (1) knowledge, (2) persuasion, (3) decision, (4) implementation, and (5) confirmation. Figure 1 illustrates the five stages of Rogers’ IDT.

1. Knowledge includes two components: awareness and how-to Knowledge. Individuals must first become aware of the innovation and then learn how to use it correctly. A lack of how-to knowledge often leads to the rejection of the innovation.

2. Persuasion involves individuals evaluating the characteristics of the innovation, including its relative advantages, complexity, compatibility and observability, and forming an opinion about it. The perceived characteristics of the innovation strongly influence the rate of its adoption.

   • Relative advantages refer to the extent to which an innovation is seen as better than the idea it replaces. Social actors are more inclined to adopt an innovation if they believe it offers greater advantages compared to maintaining the status quo (Al-Jabri and Sohail, 2012; Rogers, 2003).

   • Compatibility measures how well an innovation aligns with the existing values, experiences, and needs of potential adopters. Innovations that conflict with a social system's norms often face resistance, as they require changes to established value systems (Kale and Arditi, 2010; Rogers, 2003).

   • Complexity describes the difficulty of understanding and using an innovation; simpler innovations are adopted more quickly, while complex ones experience slower uptake. Complex innovations often require potential adopters to acquire significant new knowledge and skills, which can act as a barrier due to the considerable time and effort involved (Kale and Arditi, 2010; Rogers, 2003; Tornatzky and Klein, 1982).

   • Observability refers to how easily the outcomes of an innovation can be seen by others. The more visible the outcomes, the more likely people are to adopt it.

3. Decision follows persuasion, during which individuals determine whether to adopt or reject the innovation based on their evaluation.

4. Implementation occurs when the innovation is put into actual use. At this point, the focus shifts from mental deliberation to practical application.

5. Confirmation involves individuals or organisations seeking reinforcement for their decision to adopt the innovation, but they may reconsider or reverse this decision if exposed to conflicting information or negative outcomes (Franceschinis et al., 2017; Rogers, 2003).

According to Rogers (2003), the process of adopting new ideas and innovations, even when they offer clear benefits, is often slow and can take years. Although the concept of CE was first introduced in the 1990s (Pearce and Turner, 1990), awareness and adoption of CE remain limited within the construction industry (Bertozzi, 2022). Circular design represents an innovation that challenges conventional economic models and can radically transform existing business models and industrial practices (Veyssière, 2021). Effective implementation of such innovations requires a clear understanding of the barriers that hinder their diffusion (Suprun and Stewart, 2015). To explore these barriers, this study uses IDT to identify factors hindering the adoption of CE design strategies as an emerging innovation in the MTC industry. IDT offers a structured approach to examining how innovations spread, with particular focus on the early stages of diffusion, knowledge and persuasion, which shape individuals’ decisions to adopt or reject an innovation. In this research, barriers to adopting CE design strategies are examined through the lens of knowledge and the perceived characteristics of the innovation. This includes evaluating both the awareness of CE design strategies among MTC experts (awareness-knowledge) and their ability to apply these strategies in practice (how-to knowledge). Understanding these factors, along with experts’ perceptions of the characteristics of CE design, provides insights into the reasons behind adoption or rejection decisions.

IDT's relevance is further supported by its successful application in prior construction-related studies, examining the adoption of innovative technologies. These include research on the adoption of building information modelling (BIM) (Poirier et al., 2015; Gledson and Greenwood, 2017; Oyuga et al., 2023; Kaushalya et al., 2024), computer aided design technology (Kale and Arditi, 2005), information communication technology (ICT) (Peansupap and Walker, 2005, 2006), and off-site construction (Dou et al., 2019), making it a suitable framework for this investigation. For example, Gledson and Greenwood (2017) applied IDT to analyse how the perceived characteristics of the innovation influence the adoption of 4D BIM in the UK construction industry. Similarly, Kaushalya et al. (2024) used IDT to identify barriers to BIM adoption in Sri Lanka's construction industry. They mapped their findings to the five stages of diffusion and proposed strategies to facilitate the wider adoption of BIM innovations within the sector. Dou et al. (2019) also employed IDT to examine factors influencing the diffusion of off-site construction technologies in China. These examples highlight the relevance of IDT as a theoretical lens for analysing the diffusion of CE design as an innovative practice within MTC. While previous studies have examined different stages of Rogers’ IDT depending on their research focus, this study is limited to the first three stages of the diffusion of innovation, leading to the critical point where a decision to adopt or reject CE design strategies is made. The implementation and confirmation stages fall beyond the scope of this research, as CE design strategies have not yet been widely adopted in the MTC industry. Moreover, examining these later stages would require a different set of empirical observations focused on the practical application and long-term reinforcement of CE practices.

Figure 2 shows the research methodology used in the study. This research employed semi-structured interviews to explore the perceived barriers to adopting CE design strategies in the MTC industry. As prior experience with MTC projects was a prerequisite for participation, snowball sampling was used to recruit suitable participants. This technique improves the representativeness of hard-to-reach populations by recruiting new participants through referrals from those already interviewed (Mweshi and Sakyi, 2020; Naderifar et al., 2017). Data collection continued until data saturation was achieved (Mason, 2010; Saunders et al., 2018). Data saturation refers to the point at which information from participants becomes repetitive and no new insights emerge (Kyngäs, 2020; Urquhart, 2013). In total, 28 participants were interviewed across Australia, including architects, structural engineers, manufacturers, and professionals with combined experience in both structural design and manufacturing roles. Saturation was reached after 20 interviews; however, data collection continued to 28 interviews to confirm saturation.

Prior to the interviews, participants were emailed a participant information sheet outlining the study and their role in the research. A consent form was also provided via email, requiring participants to sign and confirm their voluntary participation. Participant anonymity was maintained in accordance with the approved human research ethics protocol. As participants were located across various states, interviews were conducted online via Zoom or Microsoft Teams. Each session lasted between 20 and 100 minutes, with an average duration of 50 minutes. Table 2 presents the organisational types, professional backgrounds, and years of experience of the participants.

The interview questions were developed based on a review of CE adoption barriers and the study's theoretical framework. The interview guideline included questions regarding participants' demographics, their knowledge of CE design, specifically both awareness-knowledge and how-to knowledge, and their perceptions of innovation characteristics (i.e. compatibility, observability, complexity, and perceived disadvantages), with the aim of identifying barriers to the adoption of CE design in MTC. This ensured alignment with the research objectives and theoretical framework. The guideline was reviewed by two academics with expertise in CE in construction to enhance the clarity and reliability of the questions, as recommended by Yeong et al. (2018). The interview guideline is provided in the supplementary material. The interviews were recorded and transcribed for data analysis, which was supported by QSR NVivo 14 software. Deductive (theoretical) thematic analysis was applied to the data collected from the semi-structured interviews (Braun and Clarke, 2006). This approach is frequently used to systematically identify, analyse, and report patterns (themes) within data (Fereday and Muir-Cochrane, 2006). Unlike inductive analysis, which allows themes to emerge from the data, deductive analysis is theory-driven, using predefined concepts to guide interpretation. Since this study was framed by IDT, a deductive approach was appropriate (Braun and Clarke, 2006; Fereday and Muir-Cochrane, 2006; Saunders et al., 2018). The analysis followed six phases: data familiarisation, coding, theme identification, theme review, theme definition, and reporting (Braun and Clarke, 2006).

To analyse data on participants’ awareness of the CE concept, their responses were evaluated using the 9R framework of CE principles defined by Kirchherr et al. (2017), which includes: rethink, reduce, reuse, repair, refurbish, remanufacture, repurpose, recycle, and recover. Elements of IDT were used to analyse the data concerning barriers to the adoption of CE design strategies within MTC. The thematic analysis was structured around the core elements of IDT, including the knowledge stage of the innovation-decision process and the perceived characteristics of the innovation. Within the context of CE design adoption in MTC, knowledge referred to professionals' awareness and understanding of CE design strategies and their capability to apply these strategies effectively in practice. Observability captured the extent to which the outcomes of CE design are visible within the industry, such as through completed MTC projects that exemplify material reuse or design for disassembly. Compatibility represented the degree to which CE design practices align with prevailing industry norms, values, and established processes and standards. Complexity reflected the difficulties associated with implementing CE design strategies. Finally, perceived disadvantages encompassed the cost, time, and risk considerations practitioners associate with adopting CE design compared with conventional construction methods.

Each coded barrier was reviewed and assigned to the most relevant stage of the innovation-decision process or perceived characteristics of the innovation, based on its conceptual fit. For instance, “lack of data on CE design risks, costs, and benefits” was classified under observability, as it reflects limited visibility of the potential benefits and challenges associated with adopting CE design practices. These definitions informed the deductive coding framework used to categorise empirical barriers and ensured a consistent connection between the IDT constructs and the themes emerging from the interview data. An example of the coding process is presented in Figure 3, which illustrates how interview excerpts were coded into subthemes and overarching themes.

The interviews identified 38 barriers, which were grouped into five overarching categories aligned with the elements. Nine subcategories emerged from steps three to five of the thematic analysis, representing specific themes within each category. These themes were then reviewed to ensure consistency with both the coded data and the overall dataset. The next section outlines the themes resulting from this analysis.

This section discusses the key barriers to adopting CE design, as identified by MTC industry experts based on interview findings. A visual summary of the results is presented in Figure 4, which groups the barriers under their respective IDT categories. A comprehensive list of these perceived barriers is provided in Table 3.

According to IDT, knowledge is the first stage in the innovation adoption process (Rogers, 2003). This category of barriers is related to the limited awareness and practical knowledge of CE design strategies within the MTC sector, which may hinder their effective adoption.

To assess the level of CE awareness among MTC industry experts, participants' awareness was evaluated against the 9R framework. They were also asked to assess general CE awareness within the MTC sector. The analysis revealed that, while key actors such as architects and structural designers are generally familiar with the concept of CE, their understanding of its principles and design strategies remains limited. Most participants associated CE primarily with reuse and recycling at the building’s EOL stage, overlooking CE practices at the design phase. Moreover, the result showed that the MTC sector tends to view mass timber as a circular material due to its bio-based nature and embodied carbon. However, it is often used without fully integrating CE design strategies into the building’s initial design process. This was highlighted by P14, who commented: “They immediately will tell you timber is the best construction material for circular economy, but then apart from a generic claim, which is supported by the fact that it is, yes, renewable, it grows back etc, but then there's not much more than this.” This reflects a narrow understanding of CE and its principles, which hinders the knowledge stage of innovation adoption. Several Interviewees also indicated that, although their organisations are aware of CE concept, it has yet to be embedded in their policies. This highlights a gap between awareness and practical application. It is also important to note that the data were collected from participants representing large development companies, consultancies, and mass timber manufacturers, all of which have access to greater financial and expert resources.

The general lack of practical knowledge within the industry limits the effective implementation of CE design strategies. Participants highlighted that the mass timber industry, particularly in Australia, is still maturing, with limited expertise in designing mass timber buildings and even fewer professionals skilled in integrating CE strategies. P10 commented: “I think getting more engineers and architects skilled in general, not necessary for circular economy, getting more skilled in general to be able to design with timber effectively is probably where we could spend some energy.” Participants attributed this gap to insufficient training programs, a lack of focus on CE in formal education, and the relatively recent emergence of CE as a priority in the construction sector.

In the context of CE design within the MTC sector, a critical observability-related barrier is the absence of real-world demonstration projects. The following section explains how the lack of demonstrable applications of CE design strategies in practical settings hinders their broader adoption in MTC.

One barrier highlighted by participants is the lack of real-world examples demonstrating the application of CE design strategies in mass timber buildings. This absence leaves stakeholders without concrete evidence to evaluate the practical implementation, risks, and benefits of CE design, resulting in uncertainty around adoption. As P7 explained: “There is a lot of opportunity that might outweigh the risk … but I think until somebody tries it, we won't know.” Another issue is the lack of long-term data on mass timber buildings. P11 noted: “I think the other disadvantage of mas timber is probably that it's still relatively new. We don't have a lot of buildings in mass timber that have been around for 100 years or maybe even 50 years. So, there's not a lot of proof cases … it's very hard to show anyone a building that's 50 years old in mass timber that is being pulled apart and can be reused.” This lack of case studies also makes insurers hesitant to cover circular mass timber structures, further slowing industry adoption.

In the context of CE design strategies within the MTC sector, compatibility-related barriers include regulatory and policy gaps, market constraints, and cultural resistance. The following section discusses these barriers in more detail.

A key barrier to the adoption of CE design strategies is their incompatibility with current building codes. CE design requires simplicity and flexibility. However, exiting codes, especially concerning fire safety, durability, acoustics, and airtightness, are based on traditional construction methods and lack flexibility to accommodate innovative practices. P7 further illustrated this barrier, explaining: “I think the biggest issue is separating layers at the moment, just because of the different requirements we have for airtightness, some of the acoustic solutions, and some of the fire solutions. So, while we might be able to design a structural system that can be pulled apart, in theory, it becomes very difficult once you add all the other functional layers due to their requirements.”

Another barrier is the absence of benchmarks, rating systems, and certifications to help designers assess and validate circularity in projects. As P15 stated, “circularity can mean different things to different people”, and this ambiguity can leave designers uncertain about how to evaluate the circularity of their designs. Another major barrier is the lack of clear CE design guidelines and technical documents that can be easily followed. P5 explained that existing resources are often superficial and fail to provide the depth needed for practitioners to apply CE design effectively. P21 added that “most engineers are not comfortable to deviate from established codes.” Without clear regulatory guidance or standards, engineers remain hesitant to explore new approaches.

The lack of established testing protocols, recertification and warranties for reclaimed timber hinders its reuse, as engineers need assurance of its structural integrity. The absence of such certifications and warranties also raises concerns for insurers, who may be reluctant to cover salvaged materials.

Some participants identified the lack of policy and regulation as a significant barrier to adopting CE design strategies. P7 noted that, despite some industry-led progress, the government has yet to mandate CE design. Many emphasised that regulatory mandates could drive change by shaping market behaviour. Participants also highlighted the lack of financial incentives, which further reduces motivation to integrate these strategies into design practices. Finally, nine participants pointed to a lack of clear ownership and responsibility for managing a building's EOL within the current regulatory framework. P7 emphasised this issue, stating, “I think there's so many layers of this ownership conundrum in there, that nobody knows who pays for it, and who benefits from it at the end of life.” This also complicates long-term contractual obligations. As P10 noted: “I don't know how you'd possibly write a contract that says in 100 years your obligation is to come back and reuse this structure.”

The lack of a formal market for salvaged components was identified as a barrier to incorporating secondary elements into design. Additionally, P9 noted that the supply of reused elements is limited, as the mass timber industry is still in its early stages. This barrier is compounded by the slow adoption of mass timber in construction. As one participant explained: “if you can get past the hurdle of actually building in timber in the first place, then circular economy becomes a much easier conversation to have” (P2). Participants also explained that perceived risks, particularly misconceptions about fire safety and durability, contribute to the industry’s reluctance to adopt mass timber. Local manufacturers also struggle to meet market demand, further slowing adoption. As a result, implementing CE design in MTC remains a secondary concern.

The construction industry's conservatism and risk-averse behaviour represent major barriers to adopting CE design strategies. Participants emphasised that the industry tends to favour traditional methods, often perceiving new systems as inherently risky. As P20 explained: “Companies don't see the value of taking the risk of experimentation.” Another participant (P13) attributed this reluctance less to actual risks and more to a fear of the unknown. Public perception and cultural resistance were also identified as barriers, with P19 noting that concepts such as regenerative design or CE often face scepticism because they challenge established norms.

The thematic analysis revealed complexity related to technical aspect of the CE design, operational and logistical complexities and technology- related complexities. These factors contribute to the perception that CE design is difficult to implement in practice, thereby slowing its adoption in the MTC sector.

Technical complexities associated with CE design strategies present another barrier to their adoption. One key barrier, as noted by participants, is that certain design decisions intended to enhance timber durability, such as the use of chemical treatments or hard-to-remove membranes, can hinder circularity. Participants proposed alternatives such as “high-performing waterproofed envelopes” and “charring the wood” to create a naturally durable, weather-resistant surface.

Another issue mentioned by several participants (P6, P7, P16, P17, P18, P21) is the lack of suitable connection systems for effective disassembly. Participants also highlighted the importance of designing in layers to facilitate disassembly, repairs, and maintenance throughout a building's lifecycle. However, existing regulations and building codes hinder the adoption of this approach, making it crucial to address these barriers first. Fire safety requirements were specifically mentioned by ten participants as another significant barrier. Fire protection measures, such as plasterboard, complicate disassembly by limiting access to, and separation of, materials. As mentioned earlier, changes to building codes and regulations could help mitigate this issue.

Uncertainty about the structural integrity of reused timber was identified as another major barrier. P21 further emphasised this concern, stating: “I have a lot of questions particularly around the strength and the capacity of the component, how well it's been looked after, does it still have the same performance as when it was put in?” These concerns increase the perceived difficulty of CE design adoption. Establishing testing protocols and recertification processes is essential to mitigate these uncertainties.

Limited technology for testing reclaimed timber poses a significant barrier to reusing mass timber components. P14 raised this concern, stating: “it's not easy, with the present technology that we have, to certify that the strength and stiffness and then the glue bond quality are still the same … If you're a certifying engineer, ensuring that all reclaimed timber meets standards based on 0.1–0.2% destructively tested samples is quite difficult.” Similarly, P20 highlighted the lack of efficient technology for testing large volumes of reclaimed timber, making the process time-consuming, costly, and suited only to bespoke applications. This illustrates a technological complexity barrier, where the perceived difficulty of applying CE design strategies reduces practitioners' confidence in their feasibility.

Another barrier, identified by participants P5, P19, and P21, is the lack of a centralised database to track and store information on salvaged components, including their availability, location, and key properties such as size, condition, and strength. This creates significant difficulties for designers and engineers, who rely on accurate data to determine whether these components meet design and safety standards for reuse. Moreover, P19 and P13 highlighted that the lack of specialised CE design tools hinders the implementation of CE strategies, and emphasised the need to integrate CE metrics, assessment tools, and visualisation features into design platforms. Without such tools, designers struggle to evaluate circularity, resulting to gaps in decision-making.

The findings indicate that MTC experts often perceive CE design strategies as costly and time-consuming. These perceived disadvantages contribute to stakeholder hesitation, especially when long-term benefits are unclear. The following section details these cost- and time-related concerns.

The higher cost of CE design strategies was frequently mentioned by interviewees. Participants noted that “the design overhead can be greater”, and that the construction phase may be more expensive due to “more complicated connections” required for disassembly. The design phase may also take longer because of the complexity involved in integrating CE strategies. Moreover, the deconstruction phase tends to be labour-intensive, time-consuming, and therefore more costly. As mentioned previously, insurance costs may also increase for circular buildings, as insurers are often hesitant to provide coverage for innovative circular mass timber systems. Delays may occur when seeking permits for CE designs, due to stricter codes and regulations. Ultimately, the intangible and long-term nature of CE benefits makes it difficult to justify the higher upfront costs, particularly when financial returns are only realised in the distant future.

The findings indicate that while MTC experts are aware of the CE concept, their understanding of its core principles remains limited. While many rate their organisations as highly aware of CE, this awareness does not necessarily translate into practical adoption (Guerra and Leite, 2021). Among CE strategies, design for disassembly and the use of secondary materials are the most widely recognised, yet they are still not fully integrated into design practices. This is partly due to the common perception that mass timber is inherently circular, which reduces the urgency to actively incorporate CE design strategies. Compounding this issue, most professionals lack the how-to knowledge needed to implement these strategies, reinforcing perceptions of complexity and further delaying adoption. This lack of knowledge also contributes to industry resistance and the persistence of established norms and practices (Cruz Rios et al., 2021; Guerra and Leite, 2021).

According to Rogers (2003), innovations that conflict with established values and norms within a social system are less likely to progress to the decision stage. The findings shows that CE design strategies face such incompatibilities with regulatory frameworks, market structures, and industry culture, making them unlikely to advance beyond the persuasion stage of the adoption process. Many experts perceive CE design as an innovation that introduces significant technical and technological complexities. Some of these complexities, such as those related to durability or fire safety requirements, are further intensified by regulatory incompatibilities. For instance, rigid building codes and the absence of clear standards for CE design amplify these technical barriers, ultimately hindering adoption (Cruz Rios et al., 2021).

Perceived disadvantages, including higher costs and longer timelines for design, construction, and deconstruction, create additional barriers. The lack of clear advantages over traditional construction methods further discourages decision-makers from embracing these strategies. Additionally, the scarcity of demonstration projects exacerbates uncertainty and reinforces the industry's risk-averse culture (Al-Jabri and Sohail, 2012; Charef et al., 2021; Rizos et al., 2016). As Rogers (2003) stated, “the diffusion of an innovation is an uncertainty reduction process”. During the persuasion stage, individuals seek information about the innovation to reduce uncertainty (Rogers, 2003). However, the lack of demonstration projects limits the visibility of both the risks and the benefits associated with CE design applications. Together, these factors contribute to a risk-averse industry mindset, making practitioners reluctant to invest in unfamiliar or unproven practices (Al-Jabri and Sohail, 2012; Charef et al., 2021; Rizos et al., 2016).

Overall, CE design strategies are perceived as incompatible with existing norms, difficult to implement, and lacking clear advantages. As knowledge is the first stage of innovation diffusion (Rogers, 2003), there is a critical need to promote both public and industry awareness and knowledge of CE principles. Integrating CE topics into university curricula and professional training programmes can not only raise awareness but also equip designers and engineers with necessary skills to implement these strategies effectively. Enhancing knowledge in this way helps to reduce uncertainty and mitigate risk aversion among industry professionals. In parallel, raising public awareness through communication channels such as mass media can help shift cultural perceptions of innovative construction methods and support regulatory reforms (Bonenberg and Kapliński, 2018; Martinich, 2016; Cruz Rios et al., 2021).

Another effective strategy to enhance adoption is the implementation of demonstration projects. These projects can serve as educational tools, raising both awareness and how-to knowledge among industry professionals. More importantly, they help reduce uncertainty by offering tangible solutions to the technical complexities involved in applying CE design strategies (Blackburn et al., 2020). Interviewees highlighted that government-funded demonstration projects can help mitigate the initial financial risks, thereby encouraging broader industry adoption. Similarly, CE consultancy services and knowledge-sharing initiatives can reduce uncertainty and accelerate the adoption process (Cruz Rios et al., 2021). Interview participants noted that, while large companies often have better access to expert advice, small and medium-sized companies often lack similar support. Given their resource advantages, participants suggested that large firms could promote broader industry adoption by offering consultancy services and sharing CE knowledge with smaller firms. This recommendation is consistent with findings reported in the literature (Rizos et al., 2016).

A lack of clear CE metrics and design guidelines creates additional uncertainty, leaving designers unsure about the circularity of their proposed designs. Furthermore, the absence of robust testing procedures, certification processes, and long-term warranties for reclaimed mass timber components exacerbates this uncertainty and discourages adoption. Establishing CE design guidelines, industry-wide standards, and certification procedures can address these concerns and encourage the use of secondary materials (Zaman et al., 2023). Collaborative research between academia and industry is essential to addressing these challenges. Such research plays a vital role in raising awareness, expanding knowledge, and developing the skills necessary for the effective implementation of CE design. When supported by empirical data, it can also demonstrate the tangible benefits of CE practices, reduce perceived risks, and offer practical solutions to overcome adoption barriers. Furthermore, researchers can work with industry partners to develop CE-specific design visualization and assessment tools, as well as comprehensive databases cataloguing the availability and properties of salvaged materials. These resources would equip designers with the information needed to make informed and confident decisions throughout the design process (Cruz Rios et al., 2021; Guerra and Leite, 2021; Munaro and Tavares, 2023).

Regulatory frameworks play a critical role in the adoption of CE design, yet outdated codes often hinder fast-paced innovations and contribute to industry inaction. Consequently, a flexible, adaptable and “innovation-friendly” regulatory framework is needed to support the adoption of CE design strategies (Martinich, 2016; Ranchordas, 2014). According to Rogers (2003), individuals often evaluate both the advantages and disadvantages of an innovation during the decision stage. Interview participants echoed this, suggesting that government incentives can significantly influence adoption decisions by enhancing the perceived benefits of CE design. Such incentives may include positive measures, such as rewarding desired behaviour, or penalties to discourage non-adoption (Rogers, 2003). Given this, regulation should provide tangible incentives such as mandating CE design, integrating CE metrics into green rating systems, introducing carbon taxes, or offering financial rewards, to motivate stakeholders to adopt CE design (Munaro and Tavares, 2023; Guerra and Leite, 2021). Additionally, clarifying EOL responsibilities through policy reform could reduce uncertainties around ownership and contractual obligation (Cruz Rios et al., 2021). Several European countries, including the Netherlands, the UK, Denmark, and Italy, have already introduced CE-focused policy programmes in the construction sector using these strategies, although such measures have yet to be widely adopted in practice (Giorgi et al., 2022).

Establishing a market for secondary materials is essential (Munaro and Tavares, 2023). Countries such as the UK and the Netherlands have already established digital exchange platforms to facilitate the reuse of secondary building materials. These platforms foster collaboration and information sharing among stakeholders across the construction value chain by connecting supply and demand for secondary materials (Giorgi et al., 2022). However, MTC is still emerging, and few mass timber buildings have reached EOL, making salvaged components relatively scarce. Therefore, encouraging wider mass timber adoption is key to ensuring the future availability of reusable mass timber elements (Zaman et al., 2022). Finally, given their substantial influence on design decisions, architects can act as agents of change by influencing clients’ decisions and encouraging them to adopt CE practices (Cruz Rios et al., 2021).

This study investigated the barriers to adopting CE design strategies in the MTC sector by applying Rogers’ IDT. Semi-structured interviews were conducted with 28 MTC professionals across Australia, including architects, engineers, and manufacturers, and the data were analysed using thematic analysis. The research focused on the knowledge and persuasion stages of the diffusion process and identified 38 distinct barriers influencing decisions to adopt or reject CE design strategies.

The findings indicate that while most professionals are aware of the CE concept, they have a limited understanding of its specific design strategies and often lack the practical skills needed for implementing them. CE strategies are also perceived as incompatible with existing regulatory frameworks, market structures, and prevailing industry culture. Additionally, they are viewed as technically and technologically complex, which contributes to their perceived difficulty in practical application. These strategies are further seen as disadvantageous due to their higher cost and extended time requirements. The absence of demonstration projects also reduces observability, heightening uncertainty and reinforcing the perception of complexity associated with implementing CE design strategies. Collectively, these barriers hinder the adoption of CE design in the MTC sector and must be addressed to support its faster diffusion.

This study contributes to both theory and practice by examining the barriers to CE design adoption in MTC through the lens of IDT. It demonstrates how the dimensions of knowledge, observability, compatibility, complexity, and perceived disadvantages influence the diffusion of CE design within the MTC sector. The findings carry clear implications for policymakers, industry professionals, and academia. For policymakers, the findings highlight that the limited compatibility of CE design with existing codes and regulations constrains its diffusion, while outdated standards also contribute to technical complexity. To enhance compatibility and reshape practitioners’ perceptions of innovation, regulatory reforms are needed to reduce these incompatibilities. Moreover, policies such as mandating CE design requirements, integrating CE metrics into green rating systems, and introducing financial incentives or carbon taxes can further support diffusion by improving the cost-benefit appeal of CE design, thus reducing its perceived disadvantages. Enhancing observability through government-led demonstration projects can further reduce uncertainty by showcasing practical feasibility and performance outcomes. Likewise, clarifying EOL responsibilities through targeted policy measures can further minimise uncertainty and accelerate the diffusion of CE design in MTC sector. Establishing digital marketplaces for reclaimed materials and transparent certification systems for secondary timber can also strengthen compatibility by aligning CE design with prevailing industry norms and practices. For industry, the findings emphasise the critical role of knowledge, awareness, and industry culture in shaping adoption behaviour. Practitioners can take proactive measures to accelerate the diffusion of CE design in MTC. For instance, large firms can support smaller companies by providing CE consultancy services and facilitating knowledge-sharing initiatives. Collaboration between industry and academia is also essential for developing suitable connection systems, CE-specific design tools and comprehensive material databases for secondary timber components, helping to reduce technical and technology related complexities. The creation of CE design guidelines, certification procedures, and industry-wide standards should be a joint effort involving government, industry, and academia to ensure practicality, regulatory alignment, and scientific rigour. For academia, the study underscores the importance of embedding CE principles and hands-on training into architecture and engineering curricula to bridge existing knowledge gaps and build future industry capacity. Moreover, the study lays a theoretical foundation for future research on CE design adoption in MTC and provides a basis for further empirical studies aimed at achieving a circular built environment.

This study has certain limitations that should be acknowledged. First, the scope of data collection was limited to MTC professionals in Australia, which may affect the broader applicability of the findings to the global MTC sector. Given that perceptions of barriers can vary significantly across countries due to differences in regulatory frameworks, market dynamics, and industry practices, future research should extend this study through comparative analyses of the Australian MTC sector and its international counterparts to identify both universal and context-specific challenges. Second, this research primarily focuses on the early diffusion stages of CE design strategies (knowledge and persuasion stages), without considering the later stages of implementation and confirmation. Further empirical studies are needed to evaluate the real-world application of these strategies, including case studies of projects that have successfully integrated CE design. Third, while Rogers’ (2003) IDT provided a useful framework for identifying and interpreting barriers to CE design adoption in MTC, its explanatory scope has certain limits. IDT effectively captures individual perceptions of innovation barriers (micro level) but is less effective in explaining how adoption unfolds within broader organisational (meso) and institutional, market, and policy environments (macro level). A system or multi-level perspective, views innovation as a dynamic process shaped by interactions between these levels rather than by isolated decisions. Integrating IDT with such system-based approaches could offer a more comprehensive understanding of how multi-level factors influence the diffusion of innovation in construction (MacVaugh and Schiavone, 2010; Gruber, 2020). Finally, future research could examine how different barriers interact and influence one another. While this study qualitatively identified key barriers using IDT, exploring their interrelationships through quantitative or system-based approaches could offer deeper insight into how various factors collectively shape the adoption of CE design in MTC.

The supplementary material for this article can be found online.