When a completed module arrives on a truck, much of its construction story has already happened. Behind its walls may be installed wiring, plumbing, insulation and interior finishes, all assembled before the building reaches its permanent address.
Volumetric modular construction brings these activities into a manufacturing environment. Each module is a three-dimensional section of a building, designed to be transported and connected to other sections on site.
Understanding what happens inside the factory helps explain how this approach changes the work of architects, engineers and construction teams.
The production process starts with design
A factory-built building needs a design that accounts for both its final use and its journey through production.
The team must coordinate room layouts, structural connections and building services with manufacturing and assembly requirements. This approach is often called Design for Manufacture and Assembly, or DfMA.
Canada’s National Research Council is developing guidance and digital workflows that connect these stages. Its prefabrication research includes factory operations, automation and the integration of design information with on-site assembly. Source: National Research Council Canada
For a project team, this makes early coordination particularly valuable. Decisions about an opening or service connection influence work that may be repeated across many modules.
A building moves through workstations
Inside a modular factory, construction can be organized as a sequence of defined tasks.
Fero International describes this process at its manufacturing facility in Hamilton, Ontario. Modules move through workstations, with each station equipped for a particular activity. Skilled trades concentrate on a focused group of tasks as the module progresses through the line. Source: Fero International — Manufacturing Facility
The sequence varies by manufacturer and building system. The underlying idea is consistent: organize people, materials and equipment around a repeatable production process.
A structural unit gradually becomes an enclosed, serviced and increasingly finished space.
More work happens before delivery
The amount completed in the factory depends on the project. Modular construction can incorporate much of the structure, building envelope, services and interior fit-out before transportation.
Meanwhile, a separate team can prepare the site and foundations. Manufacturing and site work therefore become coordinated activities that can overlap.
The Modular Building Institute identifies this parallel workflow as a central feature of off-site construction. The manufacturer and site contractor still need a shared schedule so that the building and its destination are ready at the right time. Source: Modular Building Institute
Digital twins extend planning into the factory
One developing approach is to simulate the production environment before installing the equipment.
In March 2026, MHP and ADMARES described a digital manufacturing system developed with Porsche Consulting, EDAG and Siemens Digital Industries Software. Their work uses digital twins to plan and simulate manufacturing processes, layouts and product variants.
The announcement concerns a planned smart factory. Its projected production capacity represents a design target rather than verified operating output.
The broader idea is relevant beyond that individual project: digital planning can help teams explore how design choices affect the way a building will be manufactured. Source: MHP / Porsche Newsroom
Quality depends on the process
Working indoors creates opportunities for consistent production, but the quality of the finished building depends on how the work is designed, performed and verified.
The National Research Council’s prefabrication activities include full-scale testing of manufactured building components and systems for fire safety, acoustics and airtightness.
These are building-performance questions as much as manufacturing questions. A well-organized production line must ultimately deliver spaces that work for the people using them. Source: National Research Council Canada
The factory and the site form one construction process
Factory completion is followed by transportation, lifting, structural connections and the remaining site work.
For architects and developers, the useful question is how these stages fit together. Which activities can be completed indoors? Which connections need access after installation? How will the production schedule match the site programme?
The building takes shape in the factory, but its successful delivery depends on coordination from the first drawing through final assembly.