Analysis of waste production on building construction sites: a case study of public institutional projects in Adamawa, Nigeria

Abstract

Material waste production on construction sites is related to quantity of building materials leftover and overproduced on-sites during building production process. Material management has been of concern in the building construction industry. Therefore, the study analysed waste production on public institutional project sites and achieved the following objectives: examined the factors responsible for material wastages on site, determined waste minimization and analysed cost of material waste on construction sites. Seven (7) building materials were assessed in 20 public institutional building project sites located in five (5) public higher institutions in Adamawa state selected at random. The materials include timber planks for making formwork and scaffolds used by carpenters; concrete nails used by carpenters; cement used by masons for plaster, mortar and concreting; concretes for casting structural elements; sandcrete blocks for walls construction; reinforcement bars cut to sizes used in beams, slabs and columns by iron benders; and electrical lighting wires installed in buildings by electricians. The left over quantities of each of these materials not utilised after work completion from foundation to roof level were ascertained and constituted the wastages generated on sites. Findings show that concretes for casting structural elements is the most wasted material having the highest relative importance index (RII) of 0.715. The wastage occurs in the area of poorly designed formwork for the various structural elements such as columns, beams, and slabs. With RII of 0.681, timber planks used for preparation of these formworks and scaffolds comes second. The overall total cost value of wasted materials produced by artisans in all the 20 sites is N1, 634,640 with carpenters’ contribution of 44.1%, masons’ 38.5%, iron benders’ 10.5%, and electricians’ 6.9%. It is concluded that sound procurement procedures in materials management and adequate training of artisans are vital to waste minimisation on building site.

Keywords: Artisans, Building production, Construction sites, Materials wastage