Study of Material Wastage in Masonry Construction at Building Sites in Onitsha, Anambra State

Material wastage in masonry construction contributes to elevated building costs and environmental impact, and its quantification at building sites in Onitsha, Anambra State, South East Nigeria, provides evidence for waste reduction strategies. This study quantified material wastage for cement, sand, and sandcrete blocks in masonry wall construction at 25 active building sites in Onitsha North and Onitsha South Local Government Areas. Waste was measured using the direct measurement method, tracking material delivered to site against material incorporated into the final work using a 4-week monitoring period per site. Waste factors (percentage waste over theoretical requirement) were calculated for each material. Causal factors of wastage were assessed through interviews with site foremen and artisans (n = 50). Results showed mean waste factors of 14.8% for cement, 22.3% for sand, and 9.6% for sandcrete blocks. Cement waste was significantly higher at sites using volumetric batching (mean: 17.2%) compared to sites using weight batching (mean: 8.4%). Sand wastage was highest at sites with inadequate storage (mean: 28.4% vs. 14.1% at sites with proper storage bays). Artisan skill level was a significant predictor of block waste (F = 7.34, p < 0.05). The study concludes that material wastage in Onitsha masonry construction is economically significant and recommends weight batching training, adequate material storage, and skilled artisan employment as priority waste reduction measures. Keywords: material wastage, masonry construction, cement waste, Onitsha, building cost