Prefabrication and modularization are not new concepts – in fact both have been part of the construction industry for many years, but their use has grown extensively in recent years and both are now considered to be within the “toolbox” of lean construction. Prefabrication can be defined as the process of assembling building systems to a nearly-complete state off-site, to later deliver to the project site for installation. Modularization involves constructing a finished project off-site, and then delivering it to the construction site to assemble with other modules to create the final product. The use of these types of lean construction tools, and the level of complexity involved, will vary depending on the project type.
The core benefits of utilizing modules and components which are produced in an off-site facility, and then transferred into a construction project, are that it can reduce not only individual durations, but also the overall construction program. In addition, it has the potential to reduce overall costs for the project. While one could argue that there are increased costs involved with these off-site processes for the contractor (for example the leasing of suitable premises, insurances, management of the process and transport), it also streamlines their processes, and reduces their resources and material on-site, effectively eliminating waste – the cornerstone of lean construction. With reduced labour on-site, less coordination is required; it will drive increased cost and program certainty while delivering higher quality installations.
Ultimately, the optimal solution is collaboration – utilizing contractor knowledge and pre-construction services at an early stage, and benefitting from their early involvement.
The decision to implement prefabrication or modularization on a project often occurs at the post-contractor appointment stage. However, this decision often serves better at an earlier stage, at the commencement of the design phase whereby opportunities for these tools can be sought and considered. By having contractors involved in pre-construction activities, they can add value as to where the use of prefabrication and/or modularization is appropriate when considering the constructability of a particular project. This early decision-making allows for critical design to be progressed, taking advantage of off-site prefabrication during enabling works.
Ultimately, the optimal solution is collaboration – utilizing contractor knowledge and pre-construction services at an early stage, and benefitting from their early involvement. Collaboration, when implemented, can play a critical role in the success of a project. This collaborative relationship can be achieved through strategic partnering and/or an integrated project team, which would be between the client’s team, the design team, the contractor and the supply chain. The supply chain could very well include specialists who, with their knowledge, can provide critical advice on how best to take advantage of prefabrication techniques and process – for example the prefabrication of headwalls in patient rooms in hospitals. The involvement of the integrated design team at an early stage facilitates active participation in developing the design and constructability of the project (giving early consideration to the use of prefabrication and modularization). Furthermore, it also allows for comprehensive consideration of a range of elements; the cost of constructing and maintaining the facility, health and safety implications, sustainability, design quality, speed of delivery and the operational efficiency of the completed facility.
In summary, both prefabrication and modularization are intrinsically linked with lean construction, and offer considerable benefits for a range of projects of various types and scales. Taking time early in the project to carefully consider these options, and incorporating one or both into design and design programs will improve the predictability in delivering projects on time, within budget and to a higher standard. If the project team is determined to engage in a collaborative relationship from the outset of the project, then this in itself will hopefully lead early decision making on utilizing such lean construction tools such as using prefabrication and modularization.