When Does Modular Construction Actually Pay Off? Two EAH Housing Projects Offer an Answer

Greenfield Commons I is a 100-unit garden-style community spread across multiple two-story buildings on a five-acre site in a rural part of the Salinas Valley. The draw of modular there was risk management: rural sites often mean limited subcontractor availability, and prefabricated units offered a way around that uncertainty.

MiLa, by contrast, is a single five-story building on a compact parcel in Los Altos — the city's first fully affordable housing development, expected to open in 2027. EAH won the project through a competitive RFP with Santa Clara County that specifically called for creative building techniques, and in a market where subcontractors can command steep premiums, modular looked like a way to keep costs in check.

The results tell the story. Greenfield Commons finished about three months behind schedule and over budget. MiLa, still under construction, is currently tracking roughly four months ahead of schedule and within budget. The difference comes down to geometry as much as anything else: a single tall building lets cranes move modules into place in a repetitive, efficient rhythm, while multiple low-rise buildings spread across a larger site reset that efficiency with every additional building. "Modular is not a one-size-fits-all answer," Egan said, and the two projects make the case better than any general rule could.

Even on the project that went well, modular wasn't simply a matter of ordering units and waiting for a truck. Both developments required significantly longer design coordination up front — architects, modular factories, engineering consultants, and general contractors all had to align on a shared set of specifications long before construction began. Trucking and on-site storage of completed modules also proved to be a bigger logistical hurdle than expected on both projects.

MiLa added another layer of complexity by pairing modular construction with a cross-laminated timber (CLT) podium on its ground floor — a renewable but still relatively new material in California multifamily housing, and a more expensive alternative to a standard concrete base. Getting the CLT and modular systems to work together took close coordination between the CLT manufacturer, structural engineers, and the modular factory itself.

A few lessons stood out. Modular factories operate on their own production timelines and standards, and typically warranty their units for only about a year, meaning a project's overall schedule needs to be locked in early, before that warranty clock starts running out. Financing adds its own wrinkle, since factories often require deposits and firm commitments before construction financing has even closed, so cash flow planning has to happen earlier than it would on a conventional build. Local permitting, by contrast, went smoother than expected, mainly because EAH treated it as a partnership from the start: neither jurisdiction involved had deep experience with modular construction, so early educational sessions clarifying which inspections fall under state authority versus local review ended up serving everyone well.

Looking back, Egan said he'd make one clear change on any future multi-building site: identical, linear building layouts across the board, with no L-shaped structures, to keep the modular process as consistent and efficient as possible. His broader advice for developers considering modular for the first time comes down to honesty about whether a project's physical layout actually supports it — efficiently stacked, repeatable floor plans are where modular earns its reputation for speed, and working with an architect who has real modular experience is often what separates a project that runs smoothly from one that runs into surprises along the way.