The construction industry plays a key role in a country’s economy [1], therefore, improving performance in the construction industry is vital. A construction project is commonly acknowledged as successful when the aim of the project is achieved in terms of its predetermined objectives, including completing the project on time, within budget, and to the required quality standard ^[2][3][2,3]. However, in most construction projects, severe time and cost overruns ^[4][5][4,5] and poor quality [6] have become a common phenomenon. For example, approximately 86% of construction projects experience cost overruns [7], 70% experience time overruns [8], and 10% of project materials end up as waste material [9] resulting in negative impacts on quality.

Past research proved that buildability and its further improvement could contribute to early completion of projects, savings in project costs, enhanced quality, improved safety performance, and a higher rate of productivity [10], and studies on buildability and its incorporation into construction projects therefore became popular.

Since the first emergence of the buildability concept in 1983, numerous studies have been carried out to further investigate how it could be integrated to minimize the issues that directly affect construction project time, cost, and quality. As a result, various researchers have developed rules, attributes, principles, concepts, and guidelines to incorporate buildability into construction projects to enhance construction project performance. For example, various industry research institutes have made large contributions to the buildability context. Among them, the Construction Industry Research and Information Association (CIRIA) and the Construction Industry Institute (CII) in the United States have provided guidelines for improving the buildability of building designs through several studies ^{[11][12][13][14]}[11,12,13,14]. Similarly, the Construction Industry Institute Australia (CIIA) has introduced concepts that can improve buildability during the design stage [13]. Another study conducted by [15] suggested 23 buildability concepts that were popular at the time and were referred to by many subsequent researchers. Adding to this [16] introduced a concise mode of practice of buildability concepts, dividing the above 23 concepts into three phases—the initiation phase, execution phase, and delivery phase. Giving an overview of past buildability studies, ref. [17] showed that studies published between 1987 and 2020 can be categorized into three types, namely, (1) buildability principles, (2) impact of buildability, and (3) buildability assessment systems.

A key feature of the previous studies is that their main focus is on the early stages of construction projects. Nevertheless, the study conducted by [15] has suggested additional concepts to foster buildability during the field operations phase as well. These additional concepts were mainly focused on innovation in construction methodologies and material usage rather than knowledge extraction and integration across a broader spectrum to achieve goals. Agreeing with this, ref. [16] stated that past buildability studies have only promoted buildability at a theoretical level rather than developing practical applications for better deliverables throughout the entire process to satisfy project objectives. This is because exploration of the buildability concept through its key constructs has been slow or absent over three decades [18] although the construction industry has continuously evolved when faced with aspects such as modern technologies and various societal goals.

This is further evidenced by the fact that even recent studies in this area refer to the initial definitions that emerged in the 1980s, where buildability is referred to as “ease of construction” and “integration of knowledge and experience”. These definitions were developed over 40 years ago to provide a holistic perspective at that time and to improve construction project performance. Thus, they have not been deconstructed to a level that can be considered for its practical integration. Hence, there are still issues with productivity and the achievement of overall goals due to a lack of understanding of buildability within the emerging cultural discourse. Confining buildability integration to the design stage alone is further evidence of this. Although various buildability studies have discussed practices, appraisal systems, attributes, principles, and concepts, there is little consideration given to the buildability concept through all stages of procurement. Furthermore, the discourse of buildability warrants investigation in order to understand how the basic tenets of buildability have evolved in practice over the last 30 years. Thus, the need for a renewed discourse of buildability within emerging changes in the sector is urgent so that its integration to improve performance can begin.

2. Constructability and Buildability

The review of the literature indicates that the term “constructability” has historically been used interchangeably with buildability ^{[19][20][21][22]}[19,20,21,22]. Ref. [23] stated that these two terms refer to similar concepts except in some instances where the term “constructability” had been used to explain the broader management implications of construction projects. According to the CII and CIIA, the key components of constructability include the application of construction knowledge at different work stages to achieve the overall project objectives, which is similar to the concept of buildability. Hence, some researchers argue that constructability and buildability are two identical concepts used in different parts of the world ^{[19][20][21][22][24]}[19,20,21,22,24]. The Building Construction Authority (BCA) in Singapore, which has pioneered buildability research, stated in their latest publication that “buildability” is the responsibility of the professional team and “constructability” is the responsibility of the builder [25]. Therefore, although there is no clear demarcation between these two terms, most researchers agree that both terms carry similar meanings for the enhancement of construction project performance [26]. Hence, the term “buildability” is used here to encompass both “constructability” and “buildability” terms.

3. Evolution of Buildability

Buildability deals with integrating knowledge and expertise at the right time through the most appropriate source. Although the term “buildability” had not been framed until the early 1980s, concerns about the buildability concept can be traced back to the early 1960s. For instance, studies conducted from 1960 to 1970 indicated that the lack of integration of knowledge and experience within the framework of design and construction was the origin of many complex problems [27]. Owing to this, industry reports by Sir Harold Emmerson in 1962 and the Banwell Committee in 1964 extensively discussed the consequences of poor knowledge integration such as design and construction coordination issues, poor preparation of drawings and specifications, and the inadequate level of communication between the key stakeholders. Among these, ref. [28] extensively criticized the lack of cohesion in the industry and suggested improving “knowledge sharing between the designers and contractors” to minimize the issues. This can be identified as the earliest instance at which buildability was first cited. Later, ref. [29] introduced an “integrated-team” concept consisting of “multi-skilled, multi-functional” professionals, which could be identified as a means of addressing “buildability”, although it was not coined as a terminology. Figure 1 is a graphical illustration of the evolution of the buildability concept within major construction territories. CIRIA in 1983 first defined buildability as “the extent to which the design of a building facilitates ease of construction, subject to the overall requirements for the completed building”. This definition was criticized for its narrowness in scope as it was confined to the design process [23], although buildability has impacts throughout the various work stages of a construction project and hence on the accomplishment of the ultimate project goals [14]. Since then, numerous studies have been conducted to strive for better project performance by improving buildability. Accordingly, numerous researchers have interpreted buildability based on their conceptual assumptions. For example, ref. [30] stated that buildability is “design and detailing which recognize the assembly process in achieving the desired result safely and at least cost to the client”. Elaborating on this further, ref. [31] presented a new definition: “the ability to construct a building efficiently, economically and to agreed quality levels from its constituent materials, components and sub-assemblies”. Ferguson’s definition emphasized the optimum management and structuring of project activities and building processes to achieve project goals. Adding to them, ref. [32] stated that buildability is “a philosophy, which recognizes and addresses the problems of the assembly process in achieving the construction of the design, safely as well as without resorting to standardization or project-level simplification”. An extended clarity for buildability was introduced by CIIA, deviating from its traditional focus on “lack of knowledge”, stating that buildability is about “lack of management of information” rather than “lack of information” [13]. BCA in Singapore, who reflected on the influence of buildability on productivity, defined buildability as “the extent to which the design of a building facilitates ease of construction, as well as the extent to which the adoption of construction techniques and processes affects the productivity level of building works” [25].

4. Key Constructs of Buildability

A previous study considering 11 definitions of the terms “buildability” and “constructability” that emerged over four decades (1983–2022) revealed that this concept has not evolved much over time [18]. Agreeing with this, numerous researchers confirmed that the most widely accepted and published definition was the one that CIRIA published in 1983 ^{[17][33][34][35][36]}[17,33,34,35,36]. The following Table 1 presents the studies published on buildability in construction that refer to various definitions. As per ^[11][14][26][11,14,26], three main constructs of buildability include: (01) “integrating construction knowledge and experience”, (02) “throughout the project delivery process” to (03) “achieve overall project objectives”, which are loosely focused on improving construction project performance. Agreeing with this, ref. [45] confirmed that only a little is known about the aspects that support the adoption and use of the buildability concept in construction. Therefore, to properly integrate buildability, the main constructs need to be further decomposed to derive a practical methodology for its successful integration in construction. Figure 2 above explains the deconstruction of the buildability concept following the widely used definitions.

5. Deconstruction of the Key Constructs of Buildability

Figure 2 illustrates that the concept of buildability is based on integrating knowledge and experience throughout the project delivery process, and is aimed at achieving the overall project objectives. Therefore, the “integration of construction knowledge and experience” is identified as the key driver within the buildability concept [26]. Ref. [46] described knowledge as “the individual capability to draw distinctions, within a domain of action, based on an appreciation of context or theory, or both”. There are two main types of knowledge: explicit knowledge and tacit knowledge [47]. Explicit knowledge, which is also known as “codified knowledge”, can be expressed in words and numbers and shared in the form of data, scientific formulae, specifications, manuals, and the like [48]. Tacit knowledge, on the other hand, is highly personal and embedded in individual experience [49]. Tacit knowledge therefore partly consists of technical skills that are hard to pin down [50]. Subjective insights, intuition, and hunches fall into this category of knowledge. For this reason, “tacit knowledge” is referred to interchangeably with “experience” ^[51][52][51,52] or “know-how” [50]. As per [52], the reference to tacit knowledge is context-specific. In this context, tacit knowledge is mainly acquired through industry practice and the experience of the practitioners. Researchers agree that most knowledge in the construction sector is tacit rather than explicit [53]. Most tacit knowledge resides with people [54]. Therefore, people are the main source of knowledge in construction projects. People in construction projects include the project team members or the key stakeholders and the external stakeholders. Key stakeholders are the key source of knowledge in construction. Hence knowledge sharing between the key stakeholders is vital to incorporate buildability into construction projects [55]. Construction project stakeholders, as the key source of knowledge, come from various organizations and perform in a team to deliver the construction project ^[16][56][16,56]. Therefore, the construction project team is also referred to as a temporary multi-organization [57]. To manage the knowledge within an organization, people, technology, and well-designed processes are essential [58]. The next main construct of buildability refers to the project delivery process. In the majority of the studies, there is a consensus that the design stage is critical for implementing buildability ^[59][60][61][59,60,61]. However, CII in 1987 in their “Constructability Concept File” embraced all stages in building development for integration of construction knowledge, as each had its impact on achieving the overall project requirements. Similarly, many researchers criticized limiting buildability only to the design stage and argued that improvement measures were to be carried out throughout the whole building process ^[47][62][63][47,62,63]. Therefore, all stages of construction projects must require knowledge integration in order to get maximum buildability into the construction project [44]. Thus, all the work stages in the construction project are identified as key phases for integrating knowledge. Achieving real integration of people, technology, and processes throughout entire project delivery stages is challenging, as the contributions of the team members (sources of knowledge) throughout the project delivery stages are influenced by the procurement method of the project. For example, procurement methods such as the Integrated Project Delivery (IPD) approach facilitate the integration of buildability naturally as collaboration among the stakeholders is enabled from the beginning itself and provides space for adapting modern technologies [64]. However, in procurement methods such as the traditional approach, buildability integration is difficult as this method naturally creates fragmentation among the stakeholders [65]. However, it has to be noted that the procurement method is decided irrespective of the concerns about buildability ^[66][67][66,67]. Therefore, this researchtudy focuses on buildability irrespective of the procurement method and attempts to derive key constructs that can provide guidelines for any construction project. Therefore, the selection of a suitable plan of work to capture the construction process is necessary. This plan of work has to identify the various stages in the construction process while being neutral about all the procurement methods. The RIBA Plan of Work 2020 addresses the work stages of all procurement methods as well as modern methods of construction or new drivers, such as sustainability and maintainability. The main constructs identified in the initial literesearchature review can be deconstructed as shown in Figure 3 below.