Modular Construction: The Building Method That Starts Before Construction Begins

Construction processes are usually sequential; once a crew completes a task, they move onto the next. For instance, crews cannot start building until the foundation is finished.

Modular construction operates differently. While the on-site crew prepares the foundation and utilities, modules are being built simultaneously in a controlled facility. 

Instead of completing everything at the job site, modular construction builds large portions of the structure at a separate facility and transports those sections to the job site for final assembly.

Our earlier discussion of prefab in construction serves as an introduction to modular construction. Modular construction goes beyond prefab in its focus on volumetric units. Instead of individual components or flat panels, modular construction produces complete rooms or building segments (modules).

Modular Construction vs. Prefabrication: What's the Difference?

Both prefab and modular construction involve manufacturing building elements off-site prior to their delivery to the field for installation. However, they are distinct concepts.

Prefabrication is an overarching term that describes any building element manufactured off-site, including a single structural steel truss or a prefabricated pipe spool, as well as an entire wall panel.

Modular construction is a type of prefab that includes the manufacturing of larger building sections or modules off-site prior to their transport to the job site for final assembly.

Put simply:

• Prefabrication = off-site manufacture of building components

• Modular construction = off-site manufacture of larger building sections or complete modules

How the Modular Process Works

One of the main distinctions between modular and traditional construction is the opportunity to execute several phases of a project concurrently. The Modular Building Institute states that this overlap can shorten project schedules by 30-50% relative to those employing traditional construction techniques.

Typically, the process for modular construction includes three phases:

On-site work

At the job site excavation, foundation work, and utility installation occurs. At the same time, fabrication of modules begins at an off-site location.

Off-site fabrication

Modules are manufactured in a controlled facility. Depending on the project, modules can contain the frame, insulation, drywall, flooring, electrical wiring, plumbing and finish interior surfaces.

Final Assembly

Completed modules are brought to the site and placed in position utilizing cranes and special lifting equipment. The modules are secured together and site crews make any necessary utility connections and finish work.

Benefits of Modular Construction

Faster Completion Time

One of the primary advantages of modular construction is speed. Because site preparation and module fabrication can occur concurrently, projects can often be finished sooner than with traditional construction techniques.

Reduced Delays

Due to their indoor setting, outside factors like weather affects construction much less in a controlled fabrication environment.

Improved Quality Control

Modules are created within a controlled environment enabling manufacturers to monitor production and inspect each unit. Therefore, consistency is improved among all units created during a project.

Easier Field Installation

Due to the fact that modules are partially or completely fabricated, significantly less work is performed on-site. This can lead to reduced time spent installing modules and therefore reduces disruption to on-site operations.

Less Wasted Materials

Manufacturing environments control material usage more effectively than open-field construction sites. Reduced waste can result due to more efficient use of materials.

Increased Job Site Safety

With reduced on-site activity, modular construction can provide a safer working environment for workers.

Better Organized Sites

Less traffic and activity at an on-site facility means modular construction can assist with organization on-site.

Possible Cost Savings

Time savings and labor efficiency can potentially produce cost reductions depending on a project.

Common Applications of Modular Construction

Modular construction is being utilized across numerous markets and various project types.

Although it is popularly related to residential housing, modular methods are also employed regularly in commercial, institutional and industrial settings.

Examples of application include:

• Multi-family Apartment structures/workforce housing

• Hotels/hospitality facilities

• Classrooms/Schools

• Medical offices/health care centers

• Office buildings/commercial space

• Temporary offices/site offices

• Support industrial buildings/equipment rooms

Projects with repetitive floor plans or configurations would be ideal candidates for modular construction since identical designs can be created and assembled using the same process to create additional modules.

Will modular construction be suitable for every project?

Not necessarily.

While modular construction provides several advantages over traditional construction methods, it is not suitable for every project. Several factors including building design, site accessibility, transportation logistics requirements, and ultimate project objectives will determine if a modular approach is appropriate.

Generally speaking, modular construction is particularly beneficial for projects requiring rapid completion times, high levels of efficiency during the construction period, and repeating patterns in building designs. 

Conventional construction still holds value for various reasons (e.g., complexity). Ultimately, the best approach will depend on the unique needs of your project.

Conclusion

Modular construction represents a particular form of prefabrication that relocates a substantial proportion of the building process from the job site to an off-site fabrication setting. 

By fabricating complete building sections off-site and assembling those sections at the project site, builders can accelerate the pace of construction while reducing the need for on-site fieldwork.

As schedules continue to get tighter and demand for increased efficiency increases in the industry, modular construction is rapidly gaining popularity across a vast array of markets. 

Although modular construction differs from traditional methods, similar end-goals remain — providing safe quality projects that meet deadlines.