Onsite Construction Waste Generation in Sri Lanka: Patterns, Causes, and Policy Implications

Abstract

The rapid expansion of construction activities worldwide has led to a significant increase in construction waste. It poses substantial challenges to environmental sustainability and economic stability. For effective construction waste management, accurate quantification of onsite waste generation and a clear understanding of the factors contributing to waste generation are required. This study investigates material waste generation across different contractor grades in Sri Lanka, with the following objectives: (1) to quantify and compare onsite material waste generation for key building materials among various contractor grades; (2) to identify and analyse the principal factors influencing onsite construction waste, with a focus on contractor grade differences; and (3) to review prevailing waste management practices among Sri Lankan contractors and propose methodological improvements for future waste reduction. A questionnaire survey was conducted to collect data from multiple contractor grades. Both subjective and statistical analyses of variation were used to examine the relationships. The findings revealed differences in waste percentages across contractor grades. Specially in the subjective analysis, particularly for key materials such as concrete, sand, aggregate, steel, plastic, and wood. However, statistically, there is no significant difference in total construction waste generation among the various contractor grades. It suggests that all grades contribute comparably to overall waste output. The study identified material handling inefficiencies, design-related issues, and inadequate site management as major contributors to waste. The upper-grade contractors demonstrated more advanced waste management practices. Still, specific improvements need to be made to minimise waste generation in the industry.