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The increasing awareness of environmental impacts from construction waste has aroused much public concern. Some construction organizations have included waste management as one of the major functions of construction project management. As a result, some approaches and methods for managing construction waste have been developed. Replacing wet-trade activities with prefabrication is advocated as one of the waste minimization techniques on site. However, the adoption of prefabrication is mainly confined to public housing developments in Hong Kong. This paper uses four private building projects as case studies to demonstrate the effectiveness in the use of prefabrication to minimize construction waste in Hong Kong. The wastage levels of the four projects are compared with conventional cast in-situ methods under similar project natures and conditions. The hindrances and the future trend of adopting prefabrication in Hong Kong are also examined.

Construction wastes have become the major source of solid wastes in Hong Kong. Thousands of tonnes of solid wastes are produced every year from construction and demolition activities.Increasing generation of these wastes has caused significant impacts on the environment and aroused growing public concerns. Therefore, the minimization of construction wastes has become a pressing issue. This paper aims to: i) revealing the status of construction wastes; ii) investigating the effectiveness of prefabrication in terms of waste reduction in replacing traditional wet-trade practices; iii) examining the factors that help minimize construction wastes by the adoption of prefabrication; and iv) exploring the current waste reduction situations after adoption of prefabrication by comparing with in-situ construction. It investigates wastes generated from various wet-trade construction activities such as in-situ concreting, timber formwork, bricklaying, plastering, screeding, tiling, rebar fixing and bamboo scaffolding. Six major reasons for the excessive construction wastage are known to be: i) cutting; ii) over ordering; iii) damaging during transportation; iv) losing during installation; v) poor workmanship; and vi) change of design. From the findings of a structured interview survey of thirty-one construction practitioners, "timber formwork" is found to be having the greatest potential for cutting scrap, and wastes from "poor workmanship" can be greatly reduced by adopting prefabrication in construction. Furthermore, after the adoption of prefabrication, wastage generation can be greatly reduced in various wet-trade activities including concreting, rebar fixing, bricklaying, drywall, plastering, screeding and tiling.Especially in plastering, the waste reduction can be reduced by 100%. It is concluded that

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