The construction industry is seen, by researchers, as a slowly progressing industry that is suffering from low productivity and poor performance compared to other industries. Over the past 60 years the UK industry has commissioned several reports with the aim of reviewing its performance and suggesting means of improvement. Of these, the Egan’s report, ‘Rethinking Construction’, was produced in 1998 to address concerns raised by clients engaging services of construction companies in the UK; and was followed by the ‘Never Waste A Good Crisis’ report published by construction excellence in 2009 to review the subsequent progress. The former report sent a clear message to the construction industry by stressing that:
“Recent studies in the USA, Scandinavia and this country [UK] suggest that up to 30% of construction is rework, labor is used at only 40-60% of potential efficiency, accidents can account for 3-6% of total project costs, and at least 10% of materials are wasted…The message is clear - there is plenty of scope for improving efficiency and quality simply by taking waste out of construction”1.
Although, the elimination of waste has been fundamentally used as a key driver for improvement in the manufacturing industry, and arguably led to great achievements, it has not been as prevalent in construction literature and practice 2. Construction managers have for a long time focused their attention on the transformation of activities, with little attention given to the flow of activities, leading to uncertain flow processes, increased upstream variability, expansion of non value-adding activities, and reduction of output value. In the construction industry, the idea and understanding of 'waste' among practitioners has been typically associated with the quantity of waste of materials on-site.
In their attempt to enhance the industry's performance, researchers and professional practitioners, especially within the lean construction community, have looked at the manufacturing industry as a point of reference and as a potential source of innovation - in particular lean thinking and production principles (see Figure 1). From a lean production perspective, the activities in the physics of production flow are as: value adding and non-value adding. Value means the fulfilment of customer requirements. Accordingly, waste can be simply defined as 'anything that is not required to create value for the customer/client or end-user'.
Non value-adding activities can be divided into two categories: contributory/supporting activities and unproductive activities (i.e. waste) - see Figure 1. Supporting activities are work elements that do not directly add value to output but cannot be removed , as they are essential in carrying out an operation. These include for example: logistic activities, accounting and cost-estimating activities, reading drawings, cleaning up the workplace and so on. Unproductive activities on the other hand, are those wasteful activities that are not necessary and can be eliminated from the production flow without diminishing the value of the work. These include Tachii Ohno’s seven wastes (TIMWOOD): Transportation, Inventory, Motion, Waiting, Over-production, Over-processing, and Defects. In addition, the waste of human potential - e.g. ‘Not speaking, not listening’ 3, and the ‘Making-do’4 waste can also be included within this category.
In simple words, it could be argued that the term non value-adding activity is used to differentiate between physical construction waste found on-site and other sorts of waste (i.e. Process Waste) which occur during the end-to-end design, construction and facilities management process. Empirical evidence 5, underpinned by lean thinking perspectives, points to waste in excess of 50% of construction time (see Figure 2), where waste is defined as anything that is not required to create value for the customer/client or end-users. This is primarily process waste with some physical waste.
This blog post has provided a brief overview of the concept of waste in construction. Future posts will highlight various lean initiatives for maximising value and reducing waste in construction projects. These include shedding light on imperfect procurement and contractual arrangements which are taken for granted and impede efficiency and improvement efforts in construction.
1. Egan, J. (1998) Rethinking Construction: Report of the Construction Task Force, London: HMSO
2. Koskela, L., Sacks, R. and Rooke, J. (2012) ‘A brief history of the concept of waste in production’, Proceedings of the IGLC- 20, San Diego, CA, US, 18–20, July, 2012
3. Macomber, Hal and Howell, G. (2004) ‘Two great wastes in organizations: A typology for addressing the concern for the underutilization of human potential, Proceedings for the IGLC-12, Elsinore, Denmark
4. Koskela, L. (2004) ‘Making-do-- The Eighth Category of Waste', Proceedings of the IGLC- 12, Elsinore, Denmark
5. Diekmann, J. E, Krewedl, M., Balonick, J., Stewart, T., and Won, S. (2004) Application of Lean Manufacturing Principles to Construction, Construction Industry Institute, Report No.191
6. Mossman, A. (2009) 'Creating value: a sufficient way to eliminate waste in lean design and lean production', Lean Construction Journal, 2009, 13-23.
7. Sarhan, S., Pasquire, C. and King A. (2014) ‘Institutional Waste within the Construction Industry: An outline’, Proceedings of the IGLC-22, Oslo, Norway, June, pp 895-906