Factors affecting material waste on construction sites in Nigeria

Ineffective planning and control of materials on sites can degenerate to poor performance and undesirable project outcomes as well poor public image of construction industry. This study assesses the level of contribution of several factors to material waste generation. Structured questionnaires were administered to two groups of stakeholders in construction industry. Relative contribution index, Mann-Whitney U and Kruskal-Wallis tests are used to analyse the data collected. The first three highest contributors to material waste are found to be reworks due to non-conformance to specifications, waste from cutting uneconomical shapes, and design changes and revisions with average relative contribution index of 0.801, 0.791 and 0.773 respectively. The findings reveal that there is no significant difference between the perceptions of consultants and contractorsand there is no location effect in the level of contribution of the assessed factors to material waste generation as perceived by the respondents from different locality with a p-value of 0.469. With all the factors being scored with relative contribution index greater than 0.600it is concluded that material waste generation is a critical and complex issue in Nigerian construction industry. The study recommends that all stakeholders in the construction industry should jointly consider waste minimisation strategies to reduce the level of waste generated on site