An apartment building can begin taking shape in two places at once.
At the site, crews prepare foundations and infrastructure. In a factory, another team assembles the spaces that will become homes, installing services and completing interiors before the modules are delivered.
Recent projects in California illustrate how this coordinated approach works at the scale of an entire residential building.
A module is a building block, not necessarily an apartment
Volumetric modular construction uses three-dimensional units manufactured off site and connected at their destination.
The relationship between modules and apartments depends on the design. One module may contain a complete dwelling, while another project may combine several modules into a larger home.
The Modular Building Institute describes modular construction as a process that uses familiar building materials and architectural specifications within a factory-based workflow. The resulting modules become parts of an integrated building after installation. Source: Modular Building Institute
This distinction matters when comparing projects: the number of modules does not automatically equal the number of apartments.
San Diego: 60 apartments from 78 steel modules
Domo Modular’s October 2026 project information describes its completed Hillcrest development at 3743 Fourth Avenue in San Diego.
The building contains 60 apartments assembled from 78 steel volumetric modules. According to the manufacturer, the modules were set in less than two weeks.
That figure describes the installation stage. It does not represent the full period needed for planning, manufacturing, foundations, connections and completion.
Domo’s account also identifies work remaining on site, including foundations and utilities, lifting and locking modules into position, connections between building services and final completion work. Source: Domo Modular
The project shows why factory production and site assembly need to be understood as connected stages of one delivery process.
Los Angeles: separating installation from total delivery time
A second example provides a useful comparison.
In June 2026, Model/Z announced the completion of a five-story, 66-apartment building at 6200 Broadway in Los Angeles, developed with SoLa Impact.
The company reports that its 70 modules included 66 residential units and four utility or common-area modules. Structural installation took 10 working days.
The overall construction period was much longer: work began on June 11, 2025, and the project received its Certificate of Occupancy on June 3, 2026—approximately 11.7 months later.
Both measurements are useful. One describes module installation; the other measures the period from groundbreaking to occupancy approval. Source: Model/Z — 6200 Broadway Project Announcement
What can be finished before the truck arrives?
For the Broadway project, Model/Z describes a factory process in which units move through 19 production stages on standardized steel chassis.
Flooring, cabinetry, appliances and fixtures are installed indoors. Mechanical, electrical and plumbing systems are incorporated into the production process, with quality checkpoints built into the sequence.
The level of completion changes the activities required after delivery. It also makes early coordination between the factory and site teams essential. Source: Model/Z — Manufacturing Process
Repeatable construction still needs architectural planning
A residential building must work beyond the boundaries of its individual modules.
Entrances, corridors, shared amenities and circulation determine how people move through it. The arrangement of apartments and the treatment of the exterior determine how it relates to its surroundings.
For architects, modular construction introduces a framework within which these decisions must be coordinated. The manufacturing system becomes part of the design brief, alongside the site and the needs of future residents.
Look beyond the crane
The visible installation stage can be striking: finished spaces arrive by truck and are lifted into a building that grows floor by floor.
For developers comparing construction approaches, the more useful assessment covers the complete programme. Factory production, site readiness, delivery, connections and final approvals all need to be considered together.
These projects demonstrate a practical shift in how apartment buildings can be delivered. More of the work takes place before the modules arrive, while careful coordination turns those individual spaces into a functioning place to live.