Quantification and benchmarking of construction waste and its impact on cost: A case of Pakistan

Purpose: The construction industry struggles in environmental and economic performance due to waste generation. Several studies have measured this waste in the construction industry of developing countries like India, Brazil, China, Nigeria and Iran, and proposed strategies to enhance the overall efficiency. But no such work exists in Pakistan's context. The construction industry of Pakistan contributes significantly to the country's gross domestic product (GDP). And with several mega projects in progress to overcome the energy crises and improve the infrastructure of the country, the absence of proper waste management policies and plans calls for empirical research. Therefore, this study quantifies and benchmarks material waste in the local context, its impact on project cost and the effect of multiple subcontracting arrangements on waste generation. It also proposes a conceptual waste management plan (WMP) for local conditions which can be generalized for developing countries. Design/methodology/approach: This paper uses a mixed research approach by leveraging Saunders's research onion model. To benchmark the current wastage practices, quantitative data of material waste in the Pakistani construction industry are gathered through document review of accounting systems, inventory and payment records of 40 completed building projects. Using the data, the waste rate of different materials is measured along with their impact on cost. Additionally, the role of subcontracting arrangements in waste generation is also investigated. Also, semi-structured interviews are conducted with project managers of high- and low-performing construction organizations to propose a conceptual WMP for the local industry and developing countries. Findings: The highest wasteful materials by quantity are wood, sand and concrete blocks, and those by cost are wood, bricks and steel. By quantity, 123% more material was used on average than the actual productive work. Also, the labor only (L-O) subcontracting arrangement causes maximum waste. Moreover, the difference between the highest (155%) and lowest wasting company (104%) is 51%, highlighting the proactive and resistive waste management culture and approach by the worst- and best-performing companies. Further, the impact of waste quantities is more than 2% of the project cost. Finally, a conceptual model consisting of measures at the project, industry and national levels is also proposed as a guide for developing countries. Practical implications: The findings of this benchmarking study can help improve the project planning, execution and monitoring, and control practices by providing a better understanding of the material waste potential. This will help economize the construction industry and improve its sustainability. Originality/value: This is the first benchmarking study that quantitatively measures material waste in the construction industry of Pakistan. It highlights that costly as well as sustainability-implicating materials are frequently wasted in the local construction projects. Also, this study correlates the wastage with subcontracting arrangements. Additionally, an original conceptual WMP is proposed that could help the industry improve its performance. The findings could help the construction professionals identify the loopholes in their material management practices and not only save money but also ensure better sustainability.