The Potential of Prefab: How Modular Construction Can Be Green

The modular construction approach—in which a building’s large-scale modularized components are prefabricated in an offsite manufacturing facility for rapid assembly onsite—is garnering an increasing amount of attention in the building industry. This is due in large part to the interrelated issues of the rising costs of traditional construction methods, the shortage of skilled construction labor in many areas of the country, and the worsening shortage of affordable housing. Some in the industry think that modular construction could be an effective strategy for addressing these issues. Based on research conducted by McGraw-Hill Construction, modular construction has been shown, in a majority of cases, to result in a higher-quality building delivered in a shorter time frame with more predictable costs. 

But does modular construction also have the potential to help the building industry meet its ever-more-ambitious and increasingly urgent sustainability goals? Proponents of modular construction believe it does, arguing that it can deliver greater environmental and social sustainability benefits than conventional construction can. Common claims for the sustainability benefits of modular construction include:

• reduced material waste
• reduced disruption to the building site and surrounding community
• safer working conditions
• reduced operational energy

This report will examine these and other potential benefits in depth in order to provide the foundational knowledge and integrative understanding needed to realize these benefits through effective design and project management. As with any strategy promising to enhance a project’s performance and sustainability, modular construction methods must be implemented correctly—informed by a holistic perspective and approach—to achieve the promised potential. 

Both “volumetric” and “non-volumetric” modular building systems are discussed in this report. “Volumetric” modules are individual three-dimensional units of enclosed space that are connected onsite—often used for multi-unit residential projects like hotels, dormitories, and apartment buildings. “Non-volumetric” modules are building elements that do not individually enclose space, like wall panels, interior partitions, and sections of building façade and cladding.

Although there is a lot of enthusiasm around modular construction approaches, a significant number of modular projects have encountered serious difficulties, for example around such things as transportation and weather protection. One recent, well publicized case of the potentially disastrously expensive results of modular construction poorly implemented (especially on large, ambitious projects) is 461 Dean Street in Brooklyn, which, among other issues, required a significant amount of rework due to water damage. This led to both a huge delay in completion time and a substantial cost overrun. Although modular construction may hold enormous potential for achieving sustainability goals, it is crucial to take as informed an approach as possible.