Modular offices are built in factories and then installed on-site, ready for use. The walls are erected while another team sets up the supports, and when everything is ready, the entire building is transported to the installation site.
So, how do you design a modular office building that’s built in one place and used in another? Here, we’ll explain everything from what defines a modular structure to how it’s prepared for transport and what the installation process entails so it can be used and function as an office.
What Makes a Building Modular
A modular building is partially or completely assembled in a factory, and then the construction crew installs it once it arrives on-site. Within this category of buildings, there are different types. Some include permanent foundations and remain fixed in one location, while others are designed to be disassembled and reused elsewhere.
For example, the company Nadler Modular rents, leases, and sells offices across the United States. Their modular offices leave the factory equipped with electricity, lighting, climate control, and finished interiors, ready to connect to the local grid or a generator once on-site.
Design with the Journey in Mind
Since the factory mass-produces modular buildings, the design is predefined. A last-minute change—which on a traditional construction site can be accommodated on-site—here affects modules that are already in production.
Furthermore, during the design phase, the structures must also be engineered to withstand conditions different from those faced by conventional buildings. For example, in addition to daily use, the structure of each module must withstand road transport and assembly.
Factory Testing
When working indoors, as is the case in manufacturing plants, construction takes place in series under stable conditions. While this is, in principle, good news, there is a risk of overlooking a defect, which could then recur across multiple construction projects. That is why a technical note from the Modular Building Institute recommends conducting factory testing before moving to mass production.
- Test the first installed window with a water spray test.
- Correct the defective detail.
- Retest before proceeding.
- Repeat the test every 10 to 20 modules while production is underway.
The benchmark test is ASTM E1105, which sprays water onto the window while lowering the air pressure on the interior side to simulate wind-driven rain. It is important to perform this test at the factory because, once the module is installed, the siding and other modules cover those joints.
On-site
While the module is being manufactured or transported, another team prepares the foundation and utility connections. This parallel work shortens the schedule, provided the design precisely defines how factory-built components will be joined to on-site construction.
Nadler Modular, for example, installs its portable offices using the “block and tie-down” system. The unit is supported on blocks and secured to the ground with anchors, on a reasonably level and accessible surface.
Once installed, the modular office—which was built off-site—should already be ready to accommodate workers. From the time the building is ordered until it is delivered, the process takes between one and four weeks, depending on availability and customization.