Minimizing materials wastage at the construction stage of a project through the implementation of lean construction

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Past research into the causes of waste in construction projects indicate that waste can arise at any stage of the construction process from inception, right through the design, construction and operation of the built facility. Waste in the construction industry has been the subject of several research projects around the world in recent years. It is commonly acknowledged that a very high level of waste exists in construction. Research indicates a wide variation in wastage rates of between 5%-27% of total materials purchased for construction projects in Ghana. Since construction has a major and direct influence on many other industries by means of both purchasing inputs and providing the products to all other industries, eliminating or reducing waste could yield great cost savings to the society. Lean construction considers construction materials wastes as potential wastes that hinder flow of value to the client and should be eliminated. The creation of this waste can be prevented by applying lean construction principles. The aim of the study is to advance knowledge on construction site waste minimization through the application of lean principles. The objectives of the study among others included the identification of sources and causes of material wastes on construction sites, assessment of level of knowledge of the lean concept among construction practitioners and identification of barriers to successful implementation of lean construction. The main tools for the collection of data included questionnaires, interviews and site observations. The target population for the data collection included project managers of building construction organizations and senior consultants of architectural and quantity surveying firms. Statistical package for social scientists (SPSS V 16) was employed to analyze data obtained. One sample t-test and mean score rankings were adopted to analyze data on sources and causes of materials waste respectively. Weighted average and coefficient of variation were adopted to analyze data on waste minimization measures. Mean score rankings were adopted for the analysis of data on perception of professionals on lean concepts. Factor analysis was adopted to analyze data on barriers to implementation of lean construction. Finally measures to overcome potential barriers to implementation of lean construction were analyzed by mean score rankings. Materials storage and handling, operational factors, design and documentation factors and procurement factors were considered as the main sources of waste on building construction sites. Among the causes of materials wastes are last minute client requirement, errors by tradesmen or operatives, purchased products that do not comply with specification and lack of onsite materials control. The structured questionnaire survey showed the existence of some level of awareness among professionals in the Ghanaian construction industry on the concept of lean construction. Lack of proper planning and control, lack of teamwork, poor project management, lack of technical capabilities, lack of professional motivation and poor communication between parties were considered as the six broad barriers that hinder the implementation of lean construction.  
A Thesis submitted to the Department of Building Technology, Kwame Nkrumah University of Science and Technology in partial fulfillment of the requirements for the degree of Master of Philosophy,