This report deals with issues related to construction waste. Building material that has not been built into the project is defined as construction waste. Cost of construction waste amounts to 4-12 % of the total cost of the project. Moreover, cost of construction waste is 1-3 % of the production cost.
The aim of this study is to increase knowledge about the main causes of waste within the construction industry. Measures in order to reduce material waste are analyzed. Contractors of building projects and construction workers should be able to apply methods and measures in order to reduce waste. Commissioners of building projects (the client) should be aware of amounts of waste and how this is affecting the price.
Three research questions are investigated in this report:
- What are the causes of material waste during production?
- What material is generating the largest amounts of waste, and which type of construction waste is most costly?
- What are the measures of minimizing material waste?
Methods used to investigate research questions include analysis of literature, interviews and four case studies. Three out of four case studies are performed on construction sites, where site managers are interviewed. The fourth case study is executed on a factory at Myresjöhus AB. Manufacturing of prefabricated modules is investigated.
A prefabricated wall section with a circular window during line production is analyzed in-depth. The time taken to produce a single prefabricated wall unit is measured. In addition, amounts of material waste are collected and measured. Results showed that cost of waste amounts to 2, 4 % of production cost.
Moreover, profit was 40 % of the selling price. Construction companies lack economic incentive to reduce waste costs because it is added to the selling price. Thus time becomes more important than reducing waste during production. The main cause of construction waste is lack of economic incentives to reduce levels of waste among construction companies. Secondary causes of waste are related to the efficiency of the production process.
Common material waste during site-built construction is gypsum boards, façade panels, studs, joists, insulation, and concrete molds. Waste of studs and joists amounts to 5-6 %, and concrete waste is about 2 % for each truckload of concrete. During manufacturing of prefabricated housing, the largest amounts of waste are from paneling, lining board, insulation and gypsum.
Changes have to be made to increase construction companies’ motivation to reduce construction waste within their production. The cost of waste must be visible. The client needs to be aware of costs of waste and waste management. Moreover conflicts concerning orders and material handling between contractors and subcontractors need to be solved. Moreover, construction companies need to increase the use of custom made and prefabricated modules.
In conclusion the main reason why waste levels are not decreasing is because clients are not pressuring contractors to reduce levels of waste. The most common types of waste derive from materials that have low waste fees i.e. wood. Clients need to demand information about waste charges in order to motivate contractors to reduce their construction waste.
Source: Jönköping University
Author: Junkers, Louise | Backman, Anna