On January 7, the National Institute of Building Sciences (NIBS) released a study revealing that most American construction companies use off-site construction methods for at least part of their work. But perhaps the most surprising thing about the results is that the number of workers using modular hasn’t actually gone up in the last four years.
In 2013, the NIBS established the Off-Site Construction Council (OSCC) as an "unbiased source for evaluating the applicability and potential benefits" of off-site construction. It conducted its first study of industry trends in 2014, concluding that most construction companies use some form of off-site construction. The 2018 study was commissioned to update its understanding of the marketplace.
The 2018 study surveyed 205 "construction stakeholders": management, general contractors, engineers, trade contractors, architects and developers. It found that 87.6 percent of respondents had used some type of off-site fabrication over the last year, and that 81.6 percent planned to use off-site construction the same amount or more in 2019. In comparison, 93 percent of respondents in 2014 said that they’d used off-site construction in the past year, and 83 percent said they were planning on using it again. The drop in usage isn’t significant, but it’s a good reminder that workers have been using modular since before it was a popular buzzword.
For most of the off-site users, the top benefit was speed. Off-site building allows construction companies to work on different tasks at the same time, whereas stick-built construction is far more sequential. Perhaps not surprising, 71.4 percent of the study's respondents said that the schedule advantage off-site construction provided was an important benefit, with the closest contenders being increased quality (46.4 percent) and cost-effectiveness (42.9 percent).
Despite the near-universal adoption of the approach, there are still significant barriers preventing greater adoption. When asked to rate the barriers to off-site use (0 being no barrier and 3 being a significant barrier), participants rated late design changes (2.84) and construction culture (2.72) as the biggest hindrances.
But there’s also a lot of momentum behind off-site construction. Modular housing is expected to increase by 6 percent between 2017 and 2022, driven by both a shortage in construction professionals and a drive toward greater productivity.
And the buzz surrounding off-site construction has reached outside of the construction world. In December, the British House of Lords threw its support behind off-site methods. “Off-site manufacture is likely to be more economic efficient safe and automatable than traditional home building,” said Jamie Borwick, one of the House Members. “It ought to the be the obvious thing to do.” He also called for the government to increase its use of off-site methods to serve as an example to the construction community: "for instance, prison building projects, while a leader here, could make even more use of off-site manufacturing.”
While the study includes a section where respondents can name the off-site techniques they have used (precast concrete, curtainwall assemblies, HVAC and plumbing assemblies, and metal building systems were all above 80 percent adoption), it doesn’t indicate exactly how use patterns have changed since 2014, or if construction companies are using off-site methods for more “substantial” tasks. However, it does report that off-site construction used with modular techniques (buildings made of repeated sections, or modules) has become more popular.