Lean construction finds its origins in the Toyota Production Systems (TPS). This process oriented approach is widely used in construction projects to reduce wastage of materials, time and effort in order to obtain maximum value. The most important philosophy of lean construction is “Kaizen” or continuous improvement that emphasises on making the overall process of construction transparent, reducing wastage and improving the communication between the stakeholders. Construction projects often get delayed, have frequent cost overruns, and fall short of expected quality due to inefficient project management. In construction projects, waste may surface at any stage right from the initial design phase, to construction, to the final built facility. The application of lean principles have contributed in not just improving the construction time, cost and quality but also in enhancing collaboration and coordination amongst project teams.
Improvement in project delivery, reduction in the project duration, an efficient production program, cost management, reduction in the stress levels of team members and enhancement in the overall quality of the process are some of the advantages of lean construction. Traditionally, during the construction process inventories of information, drawings, materials and work in progress etc. are built that are generally used unilaterally for risk mitigation. However, the lean approach structures and sizes inventories to function against variability.
Off-site manufacturing, prefabrication and modularisation are few effective approaches to lean construction. Standardization is another practical solution in reducing variability and ensuring efficient labour and cost performance. Participative style of project management and “Just in Time” (JIT) ordering also helps in reducing the waste during the procurement process. Some other tools of lean implementation are integrated project delivery System (LIPDS), Waste walk, 5S system, A3 reports and value stream mapping.
Information technology is another way of reducing wastage in construction projects by the use of 3D- modelling, joint IT database, building information modelling (BIM), virtual design and construction (VDU), as they help in co-ordinating design and construction. These also help to minimise extra work that is caused by frequent design changes. Lean thinking is not merely limited to implementation of new tools and technology, but requires a change in the way the organisation functions. A sustained effort of engaging people at all levels, improving customer satisfaction, exchange of ideas and learning from industry best practices are all necessary for lean implementation. Project teams need to be trained and educated about lean practices, such as JIT, total quality management (TQM) etc. in order for them to understand its relevance, else they might generate resistance.