Guest editorial: Creating capacity and capability of net zero carbon practices in the construction sector

Achieving net zero carbon in the construction sector is a relatively new concept that has gained significant global attention since the adoption of the Paris Agreement in 2015, where 196 nations pledged to limit global temperature increases to well below 2.0 °C, preferably to 1.5 °C. In alignment with this commitment, many countries have established net zero carbon targets to be achieved by the mid-century. As one of the largest contributors to greenhouse gas emissions, accounting for nearly 39% of global energy-related carbon emissions, the construction industry is uniquely positioned to drive impactful change toward achieving these targets.While global research efforts have increasingly explored various strategies to reduce carbon emissions within the sector, there remains a critical gap in consolidating knowledge emerging from cutting-edge research on net-zero carbon building design and construction practices that span the entire lifecycle of construction projects. Addressing this gap is the central aim of this special issue.This special issue focuses on the development and implementation of low-carbon design and construction practices from planning and design through to construction, operation, and end-of-life phases. It aims to unpack the potential impacts, opportunities, benefits, and barriers associated with the widespread adoption of such practices. By fostering knowledge exchange on innovative strategies, technologies, and frameworks, the issue seeks to build industry-wide capacity and capability toward a net-zero future in construction.The articles featured in this issue delve into emerging theories and examine practical applications that support the net zero carbon agenda. Through rigorous academic inquiry and practice-led insights, contributors offer a comprehensive view of how the construction industry can transition toward carbon neutrality. This special issue, thus, serves as a platform to amplify visibility and advance understanding of the systemic changes needed to transform the construction sector, ultimately contributing to a more sustainable built environment.This special issue comprises 11 papers that contribute to the reduction of embodied and operational carbon, as well as advancements in waste management and circularity, which are key pillars in achieving net zero carbon in the construction sector. The papers are organised according to their thematic focus. The first three papers (Papers 1–3) concentrate on embodied carbon (EC) reduction, exploring innovations in material selection, construction methods, and lifecycle assessment approaches aimed at minimising carbon emissions from the outset of construction projects. The next four papers (Papers 4–7) focus on operational carbon reduction, addressing energy efficiency, building performance, and renewable energy integration during the use phase of buildings. The final four papers (Papers 8–11) examine waste management and circularity, highlighting strategies such as material reuse, circular design principles and construction waste (CW) reduction practices. Together, these papers provide a comprehensive understanding of how capacity and capability can be developed across the building lifecycle to support the transition to a net-zero carbon future.Reducing EC is essential for addressing the front-end emissions associated with construction materials and processes. The first three papers present complementary strategies to achieve this goal through advanced modelling, alternative materials, and region-specific benchmarking.Paper 1 presents an integrated approach to project scheduling and resource procurement (PSRP) in construction projects, aiming to maximise net present value while minimising cradle-to-gate CO2 emissions. By incorporating a rent-or-buy strategy for renewable resources, the study introduces a novel multi-objective optimisation model that addresses both economic and environmental goals. The model is validated using benchmark datasets and a real-world water distribution construction project. Key findings reveal that transporting renewable resources results in the highest CO2 emissions during the execution phase, while non-renewable resources contribute most significantly during the production phase. This research advances the theory and application of integrated PSRP by providing a practical tool for project managers seeking sustainable outcomes.Paper 2 explores the potential of using a low-carbon geopolymer binder, composed of calcined clay and ground granulated blast furnace slag (GGBFS), as a sustainable alternative to traditional lime-based binders in hempcrete. The study tested two types of hemp hurds with different water absorption capacities. Using this combination of calcined clay and GGBFS, the new mix achieved a 30% reduction in thermal conductivity and a fourfold increase in compressive strength. Overall, the findings highlight the suitability of geopolymer binders as a promising low-carbon solution for hempcrete applications, offering enhanced mechanical and thermal performance while contributing to reduced carbon emissions in the built environment.Paper 3 provides a data-driven assessment of EC in two-storey residential buildings in Sri Lanka. Drawing on 50 Bills of Quantities, the study estimates an average EC of 0.0735 tCO2e per ft2 of gross internal floor area, with 94% of emissions linked to material production, primarily concrete, cement, timber, and sand. The study identifies key carbon hotspots and offers practical benchmarks to inform early design decisions, material selection, and carbon pricing policies, especially in developing economies.Operational carbon emissions generated during a building's use phase represent a significant and ongoing challenge. Papers 4 to 7 address this issue by focusing on technological innovation, performance-oriented design, professional awareness, and implementation frameworks for net-zero energy buildings.Paper 4 provides a systematic review and meta-analysis of over 2,600 studies on urban air pollution mitigation technologies, many of which also contribute to operational carbon reduction. The review highlights significant reductions in particulate matter and greenhouse gases through innovations such as advanced filtration systems, renewable energy technologies, green infrastructure, and smart urban planning. When integrated with policy frameworks and community engagement, these technologies form a powerful and sustainable approach to improving urban air quality. The study calls for policy integration and community involvement to scale these solutions and co-deliver environmental and health benefits.The fifth paper introduces a practical and adaptable framework for optimising thermal efficiency in residential building design, addressing the complexity and technical barriers often faced by designers. Applied to a real-world residential project in Sydney, Australia, the methodology uses Autodesk Revit for modelling and integrates parametric analysis with the NatHERS rating system to validate thermal performance improvements. Results show an average reduction of 25–33% in thermal loads, which translated to a NatHERS star rating improvement from 7.1 to 8 stars. The approach offers multiple optimised design scenarios, empowering designers to make informed, regionally relevant decisions that enhance thermal efficiency, lower energy consumption, and reduce environmental impact.Papers 6 and 7 focus on the Ghanaian context, examining awareness and implementation of net zero energy buildings (NZEBs) among construction professionals. While general awareness is high, there is a notable gap in deeper knowledge of tools like BIM, renewable energy integration, and energy-efficient practices. Paper 6 identifies this gap, while Paper 7 proposes seven strategic interventions, including training, academic engagement, policy alignment, and public education, to support widespread NZEB adoption.Together, these four studies provide a roadmap for reducing operational emissions through a mix of design excellence, technology adoption, knowledge development, and policy coordination. They emphasise the need for a holistic and locally grounded approach to achieve energy efficient, net-zero buildings.The final set of four papers (Papers 8–11) explores how construction waste management (CWM) and circular economy (CE) principles can be embedded in practice to reduce material consumption and environmental impact across the construction lifecycle.Paper 8 synthesises global knowledge on CE-aligned material strategies through a bibliometric and content analysis of over 17,600 publications (2015–2022), along with an in-depth review of 44 selected studies. Key findings highlight the effectiveness of strategies such as design for deconstruction (DfD), waste minimisation at the design stage, modular construction, on-site sorting, and reverse logistics. These approaches have been shown to reduce waste by up to 67% and cut costs by over 22%. Technologies like building information modelling (BIM) and material passports (MPs) play an essential role in enabling closed-loop systems through improved tracking, recovery, and reuse of materials. The study calls for international collaboration and standardised metrics to strengthen implementation and impact measurement.Paper 9 addresses a critical challenge in CW minimisation: information gaps during the building design phase that hinder effective decision-making. By applying interpretive structural modelling (ISM) and MICMAC analysis to expert insights from the Australian construction industry, the research uncovers the root causes of these gaps and proposes strategies to bridge them. The findings reveal that knowledge deficiencies, technical limitations, and poor collaboration are the main contributors to CW-related information gaps. These are further driven by overarching factors such as time pressure and a general lack of accessible information. The study links root causes with strategic interventions such as early stakeholder engagement, technical support, and government incentives. It offers a decision support framework to improve upstream waste planning and align with net zero objectives.Paper 10 explores the digital enablers of circular construction, focusing on how BIM, blockchain, and AI support MP systems. While BIM is widely used, the study identifies significant gaps in the integration of blockchain and AI, along with issues of data fragmentation and system interoperability. It proposes a digital integration roadmap to enhance transparency, traceability, and reuse across the construction supply chain.Paper 11 examines CWM practices in 100 public housing projects certified under New Zealand's 6 Homestar green building rating system (GBRS). Although diversion rates averaged 75.6%, most waste was downcycled rather than prevented. The study critiques the current Homestar framework for overlooking waste generation rates and recommends introducing WGR benchmarks and design-stage interventions to move toward zero-waste outcomes.Collectively, these studies underscore the importance of combining strategic foresight, digital innovation and regulatory reform, as well as on-the-ground evaluation to foster circularity and reduce CW. They contribute essential knowledge for the global transition toward low-waste, circular-built environments.The eleven papers presented in this special issue reflect a growing body of knowledge and innovation aimed at tackling one of the most urgent challenges of our time, decarbonising the built environment. Collectively, the research offers a multi-dimensional perspective across the full building lifecycle, from early planning and material choices to operational energy use and end-of-life waste management.The EC studies provide critical tools, data, and material innovations that support low-carbon construction from the outset, while the operational carbon papers offer practical frameworks and capacity-building strategies to reduce energy use and emissions during the use phase of buildings. Meanwhile, the contributions on CWM and circularity highlight how systemic thinking, digital technologies, and policy support can close resource loops and reduce environmental burden.Importantly, this special issue underscores that no single solution will suffice. Achieving net zero in the construction sector demands integrated action linking design and engineering innovation with education, policy, and digital transformation. It also requires tailoring strategies to diverse local contexts, especially in rapidly urbanising and resource-constrained regions.We hope this body of work inspires further research, cross-sector collaboration, and bold implementation efforts. By sharing both cutting-edge insights and practical approaches, this special issue contributes meaningfully to the global transition toward a low-carbon, circular, and more sustainable built environment.We acknowledge the CIB Task Group TG124 on Net Zero Carbon Building Design and Construction from where the idea for this special issue arose. Moreover, we are pleased that the knowledge advancement through papers published in this special issue contributes to meeting TG124 objectives. We would like to thank the Built Environment Project and Asset Management (BEPAM) journal team for hosting this special issue and supporting the dissemination of this important work.