Construction projects are unique and have distinctive peculiarities i.e. on-site production, one-of-a-kind production, and a delivery date. Manufacturing can be categorized as extraction, fabrication, or assembly; i.e., collecting, shaping, or joining (Ballard and Howell 1998b). Construction is a combination of fabrication and assembly. However, customization in production is becoming a characteristic in manufacturing more than ever before (Ballard and Howell 1998b). 

“Construction” in Lean Construction is viewed as the construction industry not only the construction phase. Lean Construction is defined as: “the impeccable alignment, and continuous and radical improvement of the entire supply chain, from programming to operations, in order to maximize value and minimize waste of a constructed facility” (Abdelhamid 2012).

Lean concepts are explored here to provide background on its development and potential for improving the performance of construction projects. Toyota Motor Company of Japan developed the principles of the Toyota Production System (TPS) in the late 1950s and early 1960s under the production engineering leadership of Taiichi Ohno (Ohno, 1988). The philosophy was established on the basis of eliminating all kinds of waste from production system using most efficient methods.

Established in 1993, International Group for Lean Construction (IGLC) coined the principles of Lean Construction (Howell 1999; Sarhan et al. 2017). IGLC finds construction fundamentally different from manufacturing. Therefore, reinterpreting the theory of TPS was necessary to develop a theory-based methodology for construction (Koskela et al. 2002). Koskela paved the way for implementing Lean production concepts in construction in 1992 (Abdelhamid et al. 2008). Motivated by Koskela, a new theory of production control in construction was introduced based on engineering and construction projects spanning five years (Ballard and Howell 1998a).

There are two alternatives to adapting the TPS to construction. First, peculiarities that do not fit can be eliminated by standardization, thereby allowing the direct application of TPS concepts. Second, where peculiarities cannot be eliminated, new methods must be developed to handle them (Koskela 2000). This principle was the foundation for establishing production planning and control methods in construction (namely, LPS®) which becomes the operating system of Lean Construction. LPS® is situated in the core of many implementations of Lean Construction (Tommelein 2015).

Lean production concepts from manufacturing were introduced to construction. Lean production provides a very powerful management philosophy for organizations to become more efficient and effective, focusing on three key principles called the TFV theory, namely transformation (T), flow (F), and value (V) (Abdelhamid et al. 2008; Koskela 2000). Production is defined as the flow of material and/or information starting from raw materials to the delivery of the final product, transforming inputs to outputs, while value is the fulfillment of customer requirements (Koskela et al. 2006). In accordance with this new philosophy, any construction project consists of three major flows: design flow, material flow, and workflow, plus a number of supporting flows (Koskela 1992). All of these flows are critical components to the integration across subprojects and the coordination within subprojects of MPs.

In the core of implementing Lean Construction, the Lean Project Delivery System provides the following linked opportunities to optimize the project rather than individual pieces (Mauck et al. 2009):

“Impeccable Coordination” entails predictable workflows among the trades. With traditional construction projects, on average only 55% of the work promised in a week is completed (Ballard 2000).

“Construction Projects as Production Systems” inspired by “Lean-Thinking” provides the flexibility of changing the work structure of design and construction to better allocate who does what, when, where and how to achieve Lean objectives and client requirements (values). In construction projects, production systems coupled with impeccable coordination allow for modularization, off-site fabrication, and multi-tasking to achieve the best performance.

“Construction Projects as Collective Enterprise” aligns financial incentives and creates the environment for an integrated team focusing on project performance rather than individual benefits.