The construction industry in Hong Kong has been relying heavily on traditional building technology. Buildings are usually constructed by the conventional cast in-situ method with the use of bamboo scaffolding. The construction processes are labour intensive and inevitably the quality of the work depends on the skill of the workers. The common use of sub-contractors makes management control even more difficult and few measures have been introduced to control the generation of waste on construction sites. The contractors, particularly the smaller ones, do not have sufficient capital for investment in advanced building technologies.

Recent research indicates that time and cost are the most important factors considered by contractors in the selection of construction methods or technologies for building projects. The reduction of C&D waste (for more details click here) is the least important factor in the minds of the contractors. This can be attributed to the availability of relatively inexpensive (currently free) means of waste disposal and the generally low environmental awareness of the construction industry in Hong Kong.

Improper preparation and handling, misuse, and incorrect processing are the major causes of materials wastage on construction sites. Generally speaking, more management attention is given to the materials that have a significant impact on the project cost, for example, the use of steel reinforcement. Table below shows the ranking of the major waste producing construction activities reported by the respondents of a questionnaire survey conducted by the Hong Kong Polytechnic University.

Rank: 1 – most waste, 7 – least waste

Timber formwork and wet trades (brick, tile and block laying, plastering) are identified as the major waste generation processes in the construction of buildings. These processes are labour-intensive. The wet trades are employed to construct the internal brick or block walls, fixtures and partition, and to provide decorative finishing on the structural frame. Generally a 5-10% wastage of the materials is observed.