Volumetric modular construction is a method of building that uses prefabricated, building modules that are manufactured off-site and then assembled on-site to create a finished structure. This construction method offers many benefits, including faster construction times, greater design flexibility, and improved energy efficiency.

One Mortenson example of volumetric modular construction is the citizenM hotel project in Menlo Park, CA. The hotel is constructed from fully finished shipping containers that are manufactured off-site by CIMC, a leading manufacturer of shipping containers, and then assembled on-site to create a finished structure.

The hotel is comprised of over 160 modules that make up 240 guest rooms. Each volumetric module arrives fully finished with MEP connections in a central riser shaft that runs through the building's floors. The typical module weighs around 40,000 lbs (about twice the weight of a school bus) and contains two hotel rooms and a hallway corridor in between.

In addition, the fully finished modules used in volumetric modular construction are designed to be airtight and well-insulated, which helps reduce energy consumption and improve the building's overall thermal performance. The volumetric modular construction also lends itself to benefits like weather enclosure during construction.

“There’s obviously efficiencies in doing things on the ground versus doing things at height,” Nick Pfenning, Senior Superintendent on the project, said. “But we also don’t have to worry about rain or temporary enclosure. We can fit it out, get it fully buttoned up, and bring it to the site where it has been built in a conditioned environment.”