A principal component analysis of sustainable building construction features for project delivery in South Africa

Abstract

Purpose

Successful project delivery for sustainable building construction (SBC) has been linked to certain features. Previous studies have emphasised the need to improve SBC practice in South Africa. The purpose of this study is to explore the SBC features for project delivery in South Africa.

Design/methodology/approach

A structured questionnaire elicited the primary data from 281 built environment professionals, mainly in South Africa’s Gauteng province. Descriptive and inferential statistics were used for the data analysis. This study used the principal component analysis technique to ascertain the principal SBC features.

Findings

Three components of SBC features, namely, sustainable resource use and compliance, sustainable waste minimisation and recycling and sustainable designs and materials, were developed from the principal component analysis. The factor loadings of the constituent variables ranged from 0.570 to 0.836. The reliability of each component was evaluated, and the results were 0.966, 0.931 and 0.913.

Practical implications

The revelations from this study will aid the decision-making of the relevant stakeholders towards establishing improvement initiatives and mitigating the reluctance to shift from conventional building methods and poor knowledge sharing of SBC benefits.

Originality/value

This is one of the most recent South African studies that sheds light on the components of a successful SBC deployment. The findings of this study added to knowledge by confirming three fundamental features of SBC. This study recommends adequately considering the principal features for successful SBC project delivery in South Africa.

Citation

Emere, C.E., Aigbavboa, C.O., Thwala, W.D. and Akinradewo, O.I. (2024), "A principal component analysis of sustainable building construction features for project delivery in South Africa", Journal of Engineering, Design and Technology, Vol. ahead-of-print No. ahead-of-print. https://doi.org/10.1108/JEDT-01-2024-0015

1. Introduction

Sustainable building construction (SBC) is the answer to curb the significant threat and deleterious effects of the conventional activities of the construction industry towards the climate, environment, human health and national economies (Krizmane et al., 2016; Omopariola et al., 2022). The construction industry is one of the most resource-intensive industries using raw materials, water and energy and is a significant contributor to environmental pollution, ozone layer depletion and waste (Willar et al., 2020). Globally, the construction industry consumes about 40%–50% of the world's raw materials and 40%–45% of energy (Tabassi et al., 2016; Murtagh et al., 2020).

The construction industry activities in South Africa are not without an effect on the environment and natural resources. Despite ongoing efforts to improve construction practices in South Africa, the industry faces significant challenges, particularly concerning sustainability and project delivery (Bowen et al., 2014). There is pressure to deliver green buildings in South Africa, considering the challenges such as climate change, the energy crisis and ongoing water shortages (Simpeh et al., 2023). In South Africa, building construction at least leads to 23% of greenhouse gas (GHG) emissions, while emissions from its material production account for 18 mt CO₂ annually, accounting for about 4% of the total CO₂ emissions (Simpeh and Smallwood, 2020). Similarly, buildings consume about 23% of electricity and an additional 5% is used to manufacture construction products in South Africa (Emere et al., 2023). Solid waste production is estimated to be 42 million cubic meters yearly in South Africa, with most of this waste produced in Gauteng province (Aboginije et al., 2020). SBC is required to mitigate the negative environmental impacts of building construction and ensure that social and economic objectives are met (Häkkinen et al., 2016). SBC is defined as the construction of buildings in a sustainable and green way (Tabassi et al., 2016). Green and sustainable are terms that connote ecological mindfulness. Besides, SBC aims to meet environmental, social and economic objectives. The consciousness of a sustainable built environment encourages the creation of designs that better serve community members' needs, accommodate, improve occupant comfort and health and increase employee productivity (Kwofie et al., 2020; Omopariola et al., 2022). Hence, incorporating SBC principles will transform the construction industry, increase the number of green buildings (Omopariola et al., 2022) and positively contribute to achieving sustainable development goals (SDGs).

Although there is a great need to adopt SBC in developing countries and South Africa, it has yet to receive sufficient attention in practice (Simpeh and Smallwood, 2020; Emere et al., 2023). The South African construction industry (SACI) is generally slow in adopting green and sustainable building principles (Simpeh and Smallwood, 2020). Also, adoption is still in the infancy stage among property developers and clients compared to developed countries (Masia et al., 2020). There has been a reluctance to shift from conventional building construction methods (Aghimien et al., 2019) and a lack of demand for sustainable buildings/products (Marsh et al., 2021). Conventional building methods often result in environmental degradation, excessive energy consumption and waste, undermining the country's sustainability goals (Ofori, 2019). Concurrently, project delivery often suffers from inefficiencies such as cost overruns, delays and quality issues (Windapo and Cattell, 2013). Considering the challenges of the construction industry and the problems associated with conventional building methods, there is an urgent need to adopt SBC in South Africa. SBC is characterised by certain features for successful project delivery (Olanipekun et al., 2017). Hence, the current study explores the critical features for effectively implementing and delivering SBC projects. The hypothesis was that the discussed features positively affect SBC in South Africa. Besides, in South Africa, literature is still in the dark about which features are most crucial for effectively implementing SBC. Notably, studies have yet to explore the principal SBC features in SACI. Hence, this study seeks to fill this gap by using the principal component analysis (PCA) technique to reveal the principal features of SBC for effective implementation in South Africa.

2. Literature review

2.1 Adoption of sustainable building construction in South Africa

The number of green and sustainable buildings in South Africa's building stock is minimal, as is their contribution to the country's construction market (Simpeh et al., 2023). There is a great need to switch from traditional construction methods to those that align with green building principles and concepts, including adopting green features in SACI (Owoha et al., 2022). Sinha (2009) affirmed that features like energy efficiency need to be addressed more in most building practices in South Africa, including the overall neglect of green building principles. Nevertheless, the worldwide adoption of green buildings has increased awareness of green building features and projects in SACI compared to other African countries (Owoha et al., 2022).

South Africa is argued to have one of the fastest-growing green building markets that will expand professionally and technologically further (Dodge Data and Analytics [DDA], 2018). The number of construction firms that integrate green building practices into their business was predicted to rise from 28% to 48% in 2018 and 2021, respectively (Owoha et al., 2022). Besides, according to DDA (2018), South Africa has the highest green share for retrofitting existing buildings, with 49% more than the global average (37%) for green retrofits. Furthermore, between 2015 and 2019, the country certified 100 and 500 Green Star SA-rated buildings, respectively (GBCSA, 2019; Owoha et al., 2022). This suggests that the adoption rate is improving progressively.

However, the industry has significant impediments to fully adopting green/sustainable building practices. There are prevailing problems encountered in implementing SBC practices in South Africa. These problems include a lack of knowledge and awareness of the methods and technologies, limited information that will allow practical implementation of practices, absence of dependable exact cost data/information, inadequate communication on strategies, limited understanding from clients/stakeholders on the benefits and perceived high cost of sustainable building materials (Saad, 2016; Aigbavboa et al., 2017; Mashwama et al., 2020; Marsh et al., 2021). Other challenges include the use of expensive technologies, lack of effective enforcement and mobilisation of resources to support technological changes, reluctance to shift from the conventional methods and lack of client’s/stakeholders’ interest (Saad, 2016; Aghimien et al., 2019; Marsh et al., 2021). Furthermore, there is a lack of team integration among stakeholders, limited government involvement and poor knowledge sharing among the public/clients on the benefits of SBC project delivery (Aghimien et al., 2019; Simpeh et al., 2023). Interestingly, these problems are common in other developing and African countries (Ametepey et al., 2015).

2.2 Sustainable building construction implementation

Building sustainably is in increasing demand and essential to ensure that the depletion of resources is mitigated. The practice of SBC alludes to different strategies, tools and techniques used to implement building projects that are less harmful to the environment, reduce/prevent waste production, increase waste management (reuse of waste in the production of building material), advantageous to the society and profitable to the company (Willar et al., 2020). To complete a project successfully, SBC calls for adjustments to attitudes, paradigms, procedures and systems and finding answers to issues (Oke et al., 2017). The following briefly discusses the SBC features.

2.2.1 Sustainability indicators in project briefs.

Early identification of the project's primary sustainability goals and objectives is crucial (Wang and Adeli, 2014). These could be lowering carbon emissions, conserving natural resources, advancing social equity or strengthening the local economy (Tupenaite et al., 2017; Intuitix, 2023). It is necessary to decide on the project's key performance metrics. Metrics like GHG emissions, water use, waste production or social and economic effects are examples of key indicators (Wang and Adeli, 2014; Intuitix, 2023).

2.2.2 Sustainable and efficient designs.

Sustainable design considers the whole life cycle of a building and investigates approaches to decreasing the adverse environmental effects of building activities (Efthymiou et al., 2010). Wang and Adeli (2014) emphasised the essence of sustainable, efficient designs to ensure that the economic, social and ecological objectives are met. Similarly, sustainable design initiatives seek to transmute structural developments into more environmentally conscious building designs and eventually enhance the quality of life (Wang and Adeli, 2014). It also accommodates using modern building techniques such as building information modelling (BIM) and value management. BIM, for example, optimises design and integrated project delivery (Wong and Fan, 2013). It also improves quality and reduces time and cost (Gurung, 2020).

2.2.3 Sustainable structural materials.

Using sustainable structural materials minimises environmental impacts, reduces the use of resources, is cost-effective and poses no or low human health risks (Hussain and Kamal, 2015). Sustainable structural materials include timber and alternative lumber, composite bricks, composite blocks, cementitious materials, reinforced concrete/masonry alternatives and so on (Wang and Adeli, 2014; Kumar et al., 2015). For instance, Wang and Adeli (2014) recommend wood to be used as a reuse and innocuous item in low-rise buildings. Likewise, Austin Energy (2013) confirmed using alternative lumber made of recycled materials, such as composite or plastic lumber (a recyclable material made of virgin or waste plastic), to receive increasing applications, especially for outdoor decks. Besides, alternative lumber can cost less in the long run, as it requires little maintenance during its lifetime (Wang and Adeli, 2014). Furthermore, Kumar et al. (2015) identified cellular lightweight concrete blocks as an alternative to conventional bricks/blocks.

2.2.4 Usage of biodegradable materials.

According to Rautray et al. (2019), sugarcane bagasse, lime, stone dust and water can be combined to produce lightweight bio-bricks for non-load-bearing walls with excellent heat and sound insulation. Likewise, sewage sludge and fly ash have been advocated as suitable replacements for clay in brick production (Taki et al., 2020). Furthermore, Lawrence (2015) proposed using bio-based renewable materials to reduce the embodied energy of buildings and in-use energy demand. Besides, as recycled materials still use significant energy, bio-based materials offer a viable substitute for environmental sustainability (Adebowale and Agumba, 2023).

2.2.5 Decrease in generating waste.

This concerns reducing waste at the source or before ultimate disposal (Chadar and Chadar, 2017). In addition, it entails considering and applying the essential solid waste management concepts at every stage of the process, from material design to final material usage (Ugwu et al., 2021). This necessitates adopting lean techniques and industrialised building systems (Hussin et al., 2013). Reducing construction waste and improving material estimation are two benefits of assembling building components after they have been separated from the site (Jackson, 2023).

2.2.6 Promotion of waste material recyclability.

This entails promoting the conversion of waste materials into alternative forms by reprocessing before their use (Ugwu et al., 2021). Shifting to a circular economy in buildings requires recycling resources (Jackson, 2023). Adopting recycling procedures allows materials to be recycled into new goods or components rather than discarded at the end of their life cycle. Recycling lessens the need for energy, protects our resources and lessens pollution from material extraction (Ugwu et al., 2021; Jackson, 2023).

2.2.7 Usage of waste in making construction materials.

Agro-waste materials have been discovered to be beneficial in making construction materials. For example, agro-wastes like rice husk-bark ash, coal combustion fly ash and bagasse ash, were advantageous for making cementitious materials as suitable alternatives to Portland cement (Yang et al., 2019).

2.2.8 Energy consumption minimisation.

The operating energy of a building plus the embodied energy of the building materials and construction make up the building's life cycle energy (Karimpour et al., 2014). Using low embodied energy materials, designing a lightweight/efficient structure to minimise material consumption, using recycled/reusable materials, renovating buildings rather than demolishing them and using locally sourced materials are some of the methods mentioned in the literature to reduce the embodied energy of buildings (Karimpour et al., 2014; Adebowale and Agumba, 2023).

2.2.9 Consideration of supplementary energy systems.

Generating energy has been a great challenge considering the increasing global population and expanding communities that put demands on energy supply, especially electricity, for their needs (De Amorim et al., 2018). There is a great need to provide alternative energy supplies that are environmentally friendly, efficient and healthy for society (Rabaia et al., 2021). A few ecologically friendly and efficient replacements for the conventional energy market have been discovered, including renewable energy sources. One of the cheapest energy sources is solar energy (thermal and photovoltaic), used mainly in buildings (Rabaia et al., 2021).

2.2.10 Usage of renewable resources.

Biomass burners and solar thermal collectors are typical low-energy active renewable technologies (Karimpour et al., 2014). Literature suggests switching to renewable energy sources can lead to zero-energy buildings (Karimpour et al., 2014). These houses use renewable technologies, such as solar thermal, photovoltaic and wind turbines, to lower the annual energy requirements for heat and power (Bruno, 2011; Karimpour et al., 2014).

2.2.11 Minimisation of pollution and greenhouse gas emissions.

The International Energy Agency advocates for substantial reductions in CO₂ emissions in building construction to limit global warming to below 2°C (IEA, 2020). Building materials and their production play a significant role in GHG emissions, underscoring the importance of sustainable practices or choosing sustainable options (Adebowale and Agumba, 2023).

2.2.12 Usage of materials with low carbon footprint.

The construction industry, especially the building sector, must function at net-zero carbon by 2050 by the worldwide Paris Agreement on Climate Change, to which South Africa is a signatory (Green Directory, 2021). Many low-carbon footprint building materials are available for small- and large-scale construction projects. Typical building materials with a low carbon footprint and less environmental harm include bamboo, rammed earth, recycled steel and complementary cementing materials (Adebowale and Agumba, 2023).

2.2.13 Consideration of the project’s effect on air, soil and water.

Assessing the implications of construction activities, especially on air, soil and water, for mitigation is crucial. Increased dust particles in the atmosphere because of grading, filling, removals and other construction activities are some of the effects of construction on air quality (Cheriyan and Choi, 2020). Vehicle and construction equipment emissions may also influence the quality of the air. Similarly, large-scale projects typically involve significant land disturbance, including vegetation removal and topographical reconfiguration, which increase the soil's susceptibility to erosion (Rahman and Esa, 2014). Furthermore, water quality is crucial to the economy, ecology, aesthetics and recreation. Water quality changes can impact the water's aesthetic appeal or even make some uses impossible (Rahman and Esa, 2014).

2.2.14 Water usage minimisation.

Water conservation tactics and technologies are frequently disregarded components of a whole-building design plan (Ilha et al., 2009). Various strategies are revealed in the literature that can reduce the amount of water consumed through a building's life cycle (Akadiri et al., 2012). For instance, it is reducing wastewater by using water-efficient plumbing equipment, including waterless urinals, ultra-low flow toilets and urinals, low-flow and censored sinks, low-flow showerheads and water-efficient dishwashers and washing machines (Ilha et al., 2009). It also includes the dual plumbing design, which recovers non-potable water from rain or other sources and uses it for site irrigation (Ilha et al., 2009).

2.2.15 Improved use of construction resources.

A paradigm shift from the linear economy to the circular economy model is unavoidable to conserve resources and encourage their efficient use considering the physical limit of resources (Hossain et al., 2020). Hossain et al. (2020) encourage a circular economy in the construction industry to facilitate the shift to sustainable building practices. Similarly, frequent evaluations and audits of costs, regular site meetings, cost analysis and market testing are necessary to prevent resource overuse that could compromise profitability and efficacy (Fapohunda and Chileshe, 2014).

2.2.16 Protection of biodiversity and ecology.

Achieving the SDGs in general and SDG 15 in particular depends heavily on contributing a sustainable built environment to biodiversity conservation (Opoku, 2019; Fei et al., 2021). All significant stakeholders in the built environment must be involved in raising awareness of the effects of biodiversity loss because of construction activities on human health and well-being. Reducing the built environment's impact on biodiversity should be integral to policies and strategies towards a sustainable built environment (Opoku, 2019).

2.2.17 Decrease in the use of toxic materials.

One of the tenets of sustainable construction is to steer clear of harmful building materials (Wang and Adeli, 2014). Conventional building materials mostly contain toxic chemicals and toxins that can lower the air quality inside a building (Utilities One, 2023a). The release of volatile organic compounds from paints and varnishes, the toxicity of impregnating agents, materials that release toxic fumes in the event of a fire, asbestos-based materials, radioactive materials and lead plumbing are a few examples of toxins in building construction (Pacheco-Torgal and Jalali, 2011).

2.2.18 Minimisation of the use of non-renewable goods.

Lawrence (2015) posits that using non-renewable resources such as steel, cement sourced from limestone or sand and other aggregates for building envelops should be minimised and replaced with bio-based materials that consume less embodied and operational energy.

2.2.19 Green procurement.

Incorporating environmental factors into procurement/purchasing policies, plans and actions is green procurement (Liu et al., 2020). Contractors and environmental standards should be stipulated in the contract (Srinivas, 2014). The main benefit of using green procurement in construction is the enhancement of the building and construction process's financial and environmental performance (Wong et al., 2016).

2.2.20 Diminished operational and utility costs in buildings.

This is one of the significant economic benefits of SBC (Simpeh and Smallwood, 2018). During the operating phase, SBC seeks to reduce waste generation, water use and energy use (Simpeh and Smallwood, 2018; Utilities One, 2023b). Ongoing operating expenses can be significantly decreased by implementing smart building management systems, which include occupancy sensors, automated controls and efficient water fixtures (Utilities One, 2023b).

2.2.21 Usage of smart appliances.

Using smart appliances in houses/smart houses allows for efficient use/consumption of energy from automated systems to remote control of house conditions through the internet (Ko et al., 2012). Besides, using smart appliances adds to the efficient use of energy and innovation, end-user satisfaction and comfort (Willar et al., 2020).

2.2.22 Impact consideration on social background.

The social impact of a construction project should be prioritised. Social sustainability is generally understood as improving people’s well-being and quality of life (Mulholland et al., 2019). Therefore, attributes such as safety and health, impact assessment on livelihood and culture, employment, stakeholder involvement, satisfaction, human rights and project team formation with a sustainability focus should be considered (Rostamnezhad and Thaheem, 2022).

2.2.23 Compliance with regulations on sustainable practices.

The gap between green building and legislation requirements in South Africa is non-compliance with policies (Windapo and Goulding, 2015). Implementation of green practices (per se) has been “behind” legislation enacted to regulate the design and construction of green buildings (Windapo and Goulding, 2015; Emere et al., 2023). Major regulations regarding SBC in South Africa include the Green Building Council of South Africa standards (GBCSA), the Department of Public Works green building policy and the National Environmental Management Act 107 of 1998 (Windapo and Goulding, 2015; Aboginije et al., 2020).

2.2.24 Compliance with sustainability assessment measures.

Currently, South Africa is the only nation in Africa with a green building council that has both fully embraced a sustainable building evaluation methodology and is a fully certified member of the World Green Building Council (GBCSA, 2017a). GBCSA adopted Green Star SA in 2009, like the Green Star assessment tool launched in 2002 by the Green Building Council of Australia (Hoffman et al., 2020). Based on nine separate areas – each with various credits – the Green Star evaluation addresses sustainability and environmental challenges in building design, construction and usage (GBCSA, 2017b). Consequently, compliance with the assessment measures will ensure effective SBC.

3. Research methodology

The study aimed to evaluate SBC features for project delivery in South Africa. It used a deductive methodology predicated on a positivist philosophical framework and used quantitative data obtained through a questionnaire survey from experts in the built environment. The questionnaire survey was chosen because it facilitates data collection from many respondents and makes the research quantifiable and objective (Tan, 2011). The questionnaire was divided into sections A and B. Section A comprised demographic data like educational qualification, professional background, project role and industrial experience. Section B contained the SBC features. Respondents were asked to indicate the extent to which the features are essential for SBC project delivery in South Africa. A five-point Likert scale was used, which ranged from 1 (No extent) to 5 (Very high extent).

Professionals in the built environment who are knowledgeable and qualified to provide information to address the research topic were given the questionnaire. A total of 281 completed questionnaires were received, which were suitable for the analysis and surpassed the 150 respondents' threshold for factor analysis (Pallant, 2020). Convenience sampling was used instead of random sampling, which relies only on chance. Although a major disadvantage of convenience sampling is that it lacks clear generalisability (Obilor, 2023), it was found suitable to use in the context of this study. According to Etikan et al. (2016), an advantage of convenience sampling is that it is useful when randomisation is impossible, such as when the population is enormous. Hence, this sampling technique was chosen to represent the population of construction practitioners in the Gauteng province, which is approximately 333,000 (Statista, 2023), not to mention South Africa at large. In addition, the nature of the research necessitates experienced and knowledgeable respondents to contribute meaningfully. Hence, randomisation may not be suitable in achieving this goal. Besides, the convenient sampling technique is cost-effective, less time-consuming, efficient and simple to implement (Golzar et al., 2022). Therefore, it was chosen considering the limited time frame to complete the study, the availability of respondents and the willingness to participate (Etikan et al., 2016). Furthermore, the data elicited were based on respondents’ perceptions, and the researcher planned to produce hypotheses being tested in detail in upcoming studies, which makes the convenience sampling technique suitable (Golzar et al., 2022). These considerations (including the study's sample size, which enhanced the statistical power of this sampling technique) ensured that the sample represented the population. As recommended by Golzar et al. (2022), the authors also dispersed the questionnaires at various times and locations to obtain a suitable cross-section of the target population.

The Statistical Package for Social Sciences (SPSS) version 29 software produced the study results. Descriptive statistics with frequency, mean and standard deviation were used as outputs where applicable, and factors were ranked. Similarly, exploratory factor analysis (EFA) was used to collect data or explore the correlations between variables. PCA was used to reduce many correlated variables and resize the variables into a set of components (Pallant, 2020). This threshold was chosen to reduce the large data set of SBC features, thereby increasing interpretation while minimising the loss of information (Jolliffe and Cadima, 2016). Varimax method rotation and eigenvalue above one were used to extract the principal factors of SBC implementation.

Moreover, the reliability and internal consistency of the collected data were assessed based on Cronbach’s alpha threshold of 0.70. The average value for the variables was 0.978, indicating excellent reliability and internal consistency of the collected data (Pallant, 2020). Similarly, the principal factors were separately assessed with Cronbach’s alpha test, and the results exceeded the threshold. This contributed to the discriminatory validity of the study.

4. Findings

4.1 Demographical data

Results showed that respondents with Honours/Btech degrees came first at 44.8%, followed by those with master’s degrees (24.2), bachelor’s degrees (14.6), national diplomas (10.7) and doctorates (5.7%). Similarly, most of the respondents were from the background of construction management (21.4%), followed by engineering (20.6%), quantity surveying (19.6%), project management (17.1%), architecture (14.6%) and town/urban and regional planning (6.0). The fact that the sample accommodated the various backgrounds within the South African built environment helped authenticate the collected data. Regarding industrial experience, respondents with 6–10 years were predominant (19.6%), followed by 1–5 years (18.1%), 11–15 years (15.7%), 16–20 years (14.6%), 21–25 years (11.4%), 26–30 years (8.1%) and more than 30 years were the lowest ranked group. Likewise, many respondents performed the role of project managers (33.1%), followed by construction managers (17.1%), quantity surveyors (16.4%), project engineers (14.9%), principal agents (8.9%) and town planners (5.7%). Generally, the demographic data results showed that participants had enough knowledge and experience and were in an excellent position to respond to the questionnaire.

4.2 Assessing sustainable building construction features

Table 1 presents the critical SBC features for project delivery in South Africa. The respondents were asked to rate the extent to which the deliverables are essential in achieving SBC a five-point Likert scale ranging from 1 (no extent) to 5 (very high extent). The mean score (MS) and standard deviation (SD) were used as outputs to rank the measuring variables. Table 1 shows that all the variables recorded MS value ≥ 4.07 ≤ 4.41. Nonetheless, some variables were more notable than others. The first and second ranked were sustainable and efficient designs (MS = 4.41; SD = 0.726) and sustainable structural materials (MS = 4.39; SD = 0.719), respectively. The third was energy consumption minimisation (MS = 4.33; SD = 0.838), consideration of supplementary energy systems (MS = 4.33; SD = 0.820) and usage of renewable resources (MS = 4.33; SD = 0.802). However, the penultimate ranked feature was impact consideration on social background (MS = 4.12; SD = 0.910), while the least ranked was usage of biodegradable materials (MS = 4.07; SD = 0.985). Nevertheless, the MS values showed a good indication of the significance of all the variables. Furthermore, the internal consistency and reliability of the measuring variables were excellent, with Cronbach’s alpha value of 0.978 above the threshold of 0.70 (Pallant, 2020).

4.3 Principal component analysis for sustainable building construction features

This process commenced with EFA. In all, 24 SBC implementation measuring variables were examined with EFA. The Kaiser–Meyer–Olkin sample adequacy test and Bartlett's test of sphericity were done, as shown in Table 1. Kaiser–Meyer–Olkin score was 0.959, exceeding the minimal 0.6 required to continue factor analysis (Pallant, 2020). Also, Bartlett’s test of sphericity result (0.001) supported factorability. Likewise, the extraction and rotation of the variables were done with PCA and the varimax rotation method, respectively.

Three principal component factors achieved values above one and were extracted with a cumulative percentage variance of 76.440, surpassing the recommended minimum threshold of 50% (Field, 2009). The principal component 1 accounted for 66.596% of the variance explained, while components 2 and 3 accounted for 5.453% and 4.391%, respectively.

Table 2 presents the results of the rotated component matrix with the factor loadings of the SBC implementation measuring variables categorised according to the principal components. The varimax rotated component matrix was used to achieve a simple, robust structure and results that were more straightforward to identify and interpret (Tengan, 2018). With values above 0.5, the variables loading in each extracted principal component were significant. Similarly, the extracted principal components had multiple variables, suggesting reasonable results (Field, 2009). The Cronbach’s alpha test was used to ascertain the reliability/suitability of the items in each principal component, excluding variables with cross-loadings, as shown in Table 2.

4.3.1 Naming of components.

The three principal components extracted were named considering the interrelationships and loadings of the variables/items between them. Component 1 was named Sustainable Resource Use and Compliance; Component 2 was called Sustainable Waste Minimisation and Recycling; and Component 3 was named Sustainable Designs and Materials.

4.3.1.1 Component 1 – sustainable resource use and compliance.

This comprised 12 variables with their loadings, namely, Improved use of construction resources (0.788), Compliance with regulations on sustainable practices (0.781), Diminished operational and utility costs in building (0.772), Compliance with sustainability assessment measures (0.772), Water usage minimisation (0.755), Consideration of the project’s effect on air, soil, water, etc. (0.745), Impact consideration on social background (0.724), Minimisation of pollution and GHG emission (0.708), Energy consumption minimisation (0.698), Green procurement (0.686), Usage of Smart appliances (0.656) and Decrease in the use of toxic materials (0.570).

4.3.1.2 Component 2 – sustainable waste minimisation and recycling.

This comprised five variables with their loadings, namely, Promotion of waste material recyclability (0.818), Decrease in generating waste (0.787), Usage of waste in making construction materials (0.783), Minimisation of the use of non-renewable goods (0.663) and Usage of biodegradable materials (0.623).

4.3.1.3 Component 3 – sustainable designs and materials.

This comprised three variables with their loadings, namely, Sustainable and efficient designs (0.836), Sustainable structural materials (0.819) and Sustainability indicators in project briefs (0.748).

5. Discussions

The results presented in Table 1 provide valuable insights into the prioritised features for SBC implementation in South Africa, particularly concerning project delivery. Among the numerous factors evaluated, the top five SBC implementation features that received the highest rankings were sustainable and efficient designs, sustainable structural materials, energy consumption minimisation, consideration of supplementary energy systems and using renewable resources. On the other hand, the factors that received the lowest rankings were decreased use of toxic materials, impact consideration on social background and the use of biodegradable materials. Notably, all these identified factors had mean values exceeding 4.0, indicating their statistical significance at the established three-point threshold, per Kothari and Garg (2014).

The prominence of sustainable and efficient designs provides evidence of its criticality for implementing SBC in South Africa and agrees with the study's hypothesis. It echoes the findings of Wang and Adeli (2014), who emphasise the importance of holistic approaches to building construction that encompass the entire life cycle of a building. Sustainable and efficient design approaches seek to mitigate the adverse environmental impacts of construction activities, aligning well with SBC's sustainability goals (Wang and Adeli, 2014). Abruzzini and Abrishami (2022) suggest that integrating BIM and advanced digital technologies can support the decision-making process towards efficient designs.

The respondents' emphasis on sustainable structural materials corresponds with the study's proposition and provides evidence of its importance for implementing SBC in South Africa. This result aligns with the insights provided by Hussain and Kamal (2015), who highlighted the significance of using materials that minimise environmental impacts and pose minimal risks to human health. Such materials as timber and alternative lumber, composite bricks, cellular lightweight concrete blocks and so on (Wang and Adeli, 2014; Kumar et al., 2015).

The focus on minimisation of energy consumption aligns with the study's hypothesis and reveals its vitality. Therefore, emphasis should be placed on reducing the embodied and operational energy of the buildings in South Africa. This necessitates designing lightweight structures and using low-embodied energy materials (Karimpour et al., 2014; Adebowale and Agumba, 2023). Also, most buildings should be retrofitted rather than demolished (Adebowale and Agumba, 2023).

The respondents’ emphasis on consideration of supplementary energy systems and use renewable resources also agrees with the study's hypothesis and provides evidence of their criticality. This necessitates using solar energy (thermal and photovoltaic) and other alternative energy supplies that are environmentally friendly, efficient and healthy for society (Rabaia et al., 2021). Switching to renewable energy sources can lead to zero-energy buildings (Hussin et al., 2013; Karimpour et al., 2014). This underscores the importance of adopting renewable energy sources and materials in achieving sustainability goals within the construction industry.

5.1 Component 1 – sustainable resource use and compliance

The PCA results shed light on the principal elements in SBC implementation, particularly emphasising the importance of “Sustainable Resource Utilisation and Compliance” as the first principal component. Within this cluster, a range of features was identified as essential for SBC implementation. These features encompass Improved use of construction resources, Compliance with regulations on sustainable practices, Diminished operational and utility costs in building, Compliance with sustainability assessment measures, Water usage minimisation, Consideration of the project’s effect on air, soil, water and surroundings, Impact consideration on social background, Minimisation of pollution and GHG emissions, Energy consumption minimisation, Green procurement, Usage of smart appliances and Decrease in the use of toxic materials. The finding regarding the improved use of construction materials aligns with the proposition of the study. This is also consistent with Hussin et al. (2013), who stressed the importance of efficiently using construction materials to minimise the demand for non-renewable resources, thereby reducing the environmental impact of construction. This revelation also suggests the need to shift from the linear economy to the circular economy model to conserve resources and encourage their efficient use, as well as curb the challenge of resource consumption without regard for the physical limits of resources (Hossain et al., 2020). Similarly, the importance of compliance with regulations on sustainable practices and sustainability assessment measures as critical features of SBC implementation concur with the study's hypothesis. The respondents’ opinions validate the need for these features among construction practitioners and stakeholders in SACI. This revelation concurs with Windapo and Goulding (2015), who found that the gap between green building and legislation requirements in South Africa is non-compliance with policies.

This study's finding concerning water usage minimisation agrees with the notion that it is crucial to SBC. Unfortunately, water conservation tactics and technologies are the most disregarded components of a whole-building design plan (Ilha et al., 2009). This finding suggests inter-alia the reduction of wastewater by using water-efficient plumbing equipment (Ilha et al., 2009). Consideration of the project’s effect on air, soil and water and Impact consideration on social background speak volumes by their importance in this study. There is a need to keep the environmental impact assessment at the forefront of construction projects. This will enable the mitigation of pollution in the air and water and the dangers of erosion and soil loss (Rahman and Esa, 2014; Cheriyan and Choi, 2020). Similarly, emphasis should be placed on improving people’s well-being and quality of life (Mulholland et al., 2019). Therefore, to make a grave contribution to society, attributes such as safety and health, impact assessment on livelihood and culture, employment, stakeholder involvement, satisfaction, human rights and formation of the project team with a sustainability focus should be considered (Rostamnezhad and Thaheem, 2022).

The findings regarding diminished operational and utility costs in building and using smart appliances align with the study's hypothesis and suggest their criticality to SBC. Smart technologies can be used to reduce energy consumption and improve efficiency in buildings, including using automated systems and remote control via the internet (Ko et al., 2012; Utilities One, 2023a). Similarly, the findings regarding green procurement and a decrease in the use of toxic materials align with the study's hypothesis. Construction procurement and purchasing policies, plans and actions should incorporate environmental factors (Liu et al., 2020) to implement SBC effectively. Yudelson (2010) assert that green procurement and a decrease in the use of toxic materials for buildings can significantly reduce energy use, often achieving reductions of around 30%–50%.

5.2 Component 2 – sustainable waste minimisation and recycling

The second component, “Sustainable Waste Minimisation and Recycling”, highlights the importance of managing waste and recycling materials in the context of SBC implementation. This component consists of five key variables: Promotion of waste material recyclability, Decrease in generating waste, Usage of waste in making construction materials, Minimisation of the use of non-renewable goods and Usage of biodegradable materials.

The emphasis on promoting waste material recyclability, decreasing waste generation and using waste in the production of construction materials aligns with the proposition of the study, indicating their importance. The findings concur with the insights provided by Simpeh and Smallwood (2018), who underscore the essential benefits of these practices within SBC, emphasising the need to minimise waste and maximise its reusability and recycling in construction projects. Waste should be reduced at the source or before ultimate disposal (Chadar and Chadar, 2017). Adopting lean techniques and industrialised building systems can facilitate waste management (Hussin et al., 2013). Also, cementitious materials made of agro-waste can be used as suitable alternatives to Portland cement in South Africa. Moreover, the findings on minimising non-renewable goods and using biodegradable materials align with Hussin et al. (2013) and Simpeh and Smallwood (2018), who underscore the importance of reducing the reliance on non-renewable resources and adopting biodegradable materials that have a minimal environmental impact.

5.3 Component 3 – sustainable designs and materials

The third component identified through PCA, named “Sustainable Designs and Materials”, comprised three variables: sustainable and efficient designs, sustainable structural materials and sustainability indicators in project briefs. This component sheds light on the crucial aspects of design and materials within the context of SBC, which aligns with the study's hypothesis. The emphasis on sustainable and efficient designs within this component aligns with the findings of Wang and Adeli (2014), who emphasised the critical role of these designs in SBC. Sustainable and efficient designs entail approaches that encompass the entire life cycle of a building to reduce adverse environmental impacts associated with design and construction activities (Efthymiou et al., 2010). Such designs are integral to achieving SBC's sustainability goals by promoting environmentally responsible building practices.

Similarly, the recognition of sustainable structural materials as a vital feature within this component resonates with the perspectives of various scholars, including Wang and Adeli (2014) and Hussain and Kamal (2015). Priority should be given to materials that pose minimal human health risks while contributing to minimal environmental impact and resource conservation. In addition, sustainability indicators in project briefs emphasise the importance of early identification of the project's primary sustainability goals and objectives (Wang and Adeli, 2014). Objectives such as lowering carbon emissions, conserving natural resources, advancing social equity or strengthening the local economy should be decided early (Tupenaite et al., 2017; Intuitix, 2023). This ensures that SBC's environmental, social and economic objectives are effectively incorporated and achieved throughout the project’s lifecycle. Moreover, deciding the project’s key performance metrics and key indicators early enables the gathering of information that can be examined and compared to the results of related projects or industry standards for improvement (Wang and Adeli, 2014; Intuitix, 2023).

6. Conclusions, implications and recommendations

SBC is an innovative approach that is expected to transform the construction industry activities in South Africa. Several features of its implementation have been identified. Using a questionnaire survey, respondents ranked the features according to their criticality. The features were categorised into three clusters or principal components: Sustainable Resource Use and Compliance, Sustainable Waste Minimisation and Recycling and Sustainable Designs and Materials. The respondents' perspectives on the features regarding the implementation of SBC in South Africa are elucidated by these clusters.

The current study contributed to theory, methodology, policy and practice. Theoretically, studies have yet to explore the principal features of SBC implementation in SACI. Consequently, the current research fills this gap. Similarly, this is one of the recent studies in South Africa that provides insights into the features for effective implementation of SBC. Methodologically, this study used PCA techniques to reveal the principal features of SBC implementation in South Africa. Therefore, the findings added to knowledge by confirming three fundamental factors for the SBC implementation for project delivery in South Africa. They include Sustainable Resource Use and Compliance, Sustainable Waste Minimisation and Recycling and Sustainable Designs and Materials. The consciousness of these features by the construction stakeholders and built environment organisations will help curb unsustainable practices in the construction industry. Therefore, the study recommends adequately considering and prioritising the revealed principal features to implement SBC project delivery effectively. Findings from this study will enable decision-makers within construction organisations to direct improvement initiatives appropriately. It will mitigate the reluctance to shift from the conventional methods and poor knowledge sharing among the public/clients on the essence of SBC.

The findings on sustainable and efficient designs and waste minimisation suggest that modern building techniques applicable to these features, such as BIM, IBS, value engineering/management and lean techniques, should be embraced and prioritised in South Africa. The study, therefore, recommends effective enforcement and mobilisation of resources to support technological changes. Also, social acceptance of cutting-edge and innovative technologies can be achieved by deploying awareness programs by professional bodies in the built environment. Similarly, information technological specialists can collaborate with the built environment professional bodies to curb the technological barriers identified from the literature regarding cost. This can give clients and users the desired value for money in implementing SBC.

To curb the prevalent non-compliance challenge identified from the literature concerning South African built environment practitioners, the government and policymakers in the SA construction industry should make regulations/legislation regarding SBC compulsory and defaulters penalised. The GBCSA and Department of Public Works green building policies should be taken seriously. This will mitigate unsustainable practices in the built environment. The government should also be a driving force in implementing sustainable practices which will facilitate the actualisation of SDGs. Providing financial incentives to organisations prioritising SBC is also advised (Agyekum et al., 2021; Agyekum et al., 2022).

In addition, energy efficiency programs and systems and renewable energy sources like solar should be implemented and prioritised to reduce the overreliance on conventional electricity in South Africa. Moreover, sustainable materials should be prioritised in SACI. The embrace of sustainable materials with increased quality performance can lessen the frequency and intensity of maintenance and repair tasks, improving long-term productivity and increasing longevity and durability (Adebowale and Agumba, 2023).

With the insights from the value and findings of this study, the SA construction industry can contribute immensely towards achieving SDGs by aligning its activities with sustainability initiatives. Furthermore, the general results can serve as a support tool for identifying the most significant implementation features to enhance the decision of built environment professionals and stakeholders to adopt SBC.

The study has some limitations. It focused on exploring the principal features of SBC implementation. Future studies may use structural equation modelling to confirm the impact of the identified principal factors on project success. Similarly, the study was predominantly conducted in the Gauteng province because of time constraints and difficulty reaching experts from other South African provinces. Therefore, the findings of this study may not be generalised to the South African built environment. For a comprehensive view of built environment professionals' perception of SBC and its implementation features, more research can be done using data from other provinces in South Africa.

Table 1.

Critical sustainable building construction implementation features

Variable	MS	SD	Rank
Sustainable and efficient designs	4.41	0.726	1st
Sustainable structural materials	4.39	0.719	2nd
Energy consumption minimisation	4.33	0.838	3rd
Consideration of supplementary energy systems	4.33	0.820	3rd
Usage of renewable resources	4.33	0.802	3rd
Compliance with sustainability assessment measures	4.32	0.804	6th
Promotion of waste material recyclability	4.32	0.818	6th
Compliance with regulations on sustainable practices	4.32	0.772	6th
Green procurement	4.32	0.812	6th
Consideration of the project’s effect on air, soil, water, etc.	4.31	0.819	10th
Minimisation of the use of non-renewable goods	4.30	0.795	11th
Water usage minimisation	4.30	0.825	11th
Decrease in generating waste	4.29	0.828	13th
Improved use of construction resources	4.28	0.795	14th
Usage of waste in making construction materials	4.25	0.847	15th
Protection of biodiversity and ecology	4.25	0.837	15th
Usage of materials with low carbon footprint	4.25	0.833	15th
Minimisation of pollution and greenhouse gas emission	4.25	0.874	15th
Usage of smart appliances	4.24	0.852	19th
Sustainability indicators in project briefs	4.24	0.786	19th
Diminished operational and utility costs in building	4.23	0.828	21st
Decrease in the use of toxic materials	4.22	0.834	22nd
Impact consideration on social background	4.12	0.910	23rd
Usage of biodegradable materials	4.07	0.985	24th
Kaiser–Meyer–Olkin measure sampling adequacy = 0.959
Bartlett’s test of sphericity significance = 0.000
Cronbach’s alpha	0.978

Source: Author’s own work

Table 2.

Rotated component matrix for sustainable building construction implementation features

	Component
Variable	1	2	3
Improved use of construction resources	0.788
Compliance with regulations on sustainable practices	0.781
Diminished operational and utility costs in building	0.772
Compliance with sustainability assessment measures	0.772
Water usage minimisation	0.755
Consideration of the project’s effect on air, soil, water, etc.	0.745
Impact consideration on social background	0.724
Minimisation of pollution and greenhouse gas emission	0.708
Energy consumption minimisation	0.698
Green procurement	0.686
Consideration of supplementary energy systems (solar etc.)	0.674	0.505
Usage of renewable resources	0.658	0.514
Usage of smart appliances	0.656
Protection of biodiversity and ecology	0.582	0.512
Decrease in the use of toxic materials	0.570
Promotion of waste material recyclability		0.818
Decrease in generating waste		0.787
Usage of waste in making construction materials		0.783
Usage of materials with low carbon footprint	0.531	0.682
Minimisation of the use of non-renewable goods		0.663
Usage of biodegradable materials		0.623
Sustainable and efficient designs			0.836
Sustainable structural materials			0.819
Sustainability indicators in project briefs			0.748
Cronbach’s alpha	0.966	0.931	0.913

Source: Author’s own work