Skip to content

Inside the Modular Building Process

In this article, each step of the modular construction process will be explored and reasons for these advantages will be detailed.

The Advantages of Modular Construction

Modular construction (also referred to as off-site and/or volumetric construction) is growing in popularity because it offers several advantages over traditional construction. Chiefly, these advantages include:

  • Shorter construction times (leading to a quicker ROI for owners), and
  • Cost certainty (obtained through fewer mid-project changes and weather delays, and, to a lesser degree, fewer on-site injuries)

These advantages are obtained through a carefully planned design and construction process. Unlike many traditional construction projects, modular construction leverages a precise timetable and a predictable, industrialized assembly process to realize its value.

Step 1: Design approval by the regulating authorities and end users

In the modular building process, the project begins at the design phase. Architects and engineers, using building information modeling (BIM) systems and other software, create exterior and interior plans. Once plans are approved by the owner, they are submitted to the locality or third-party service for approval and building permit applications are submitted. The manufacturing of components begins once the design is finalized.

Note: Modular buildings must follow the local building codes and zoning regulations. The modular building contractor should already know the regulations that apply to the project based on the address of the physical building site and the agencies that have jurisdiction over that area.

inside-modular-process2_800x450

Modular buildings must have approved and finalized designs before construction begins.

Step 2: Construction of modular components in a controlled atmosphere

The module components are built in a controlled offsite factory environment while site excavation and grading is going on at the same time. The amount of work (60% - 90%) performed in the factory can vary based on owner requirements. For example, it can include assembling basic structural components (like exterior and interior walls, flooring, and windows), installing mechanical, plumbing, and electrical components, and completing interior finishes such as drywall and cabinets. Because so much can be accomplished off-site, the labor force in the factory can consist of any or all of the following:

  • Carpenters
  • Drywall finishers
  • Plumbers
  • Electricians
  • HVAC workers
  • Painters
  • Floor finishers, and more
inside-modular-process3_800x450

A controlled factory environment allows modules to be built quickly, precisely, and more safely.

Inspections by a third party or other building code official takes place at various stages in the factory. Upon completion of the modules, they are prepared for transportation.

Step 3: Transportation of modules to a desired location

Modular buildings are shipped on chassis integrated into the structure or carriers towed by trucks. Due to the need to transport the modules to the final site, each module must be built to independently withstand travel and installation requirements (e.g., high winds, manipulation by cranes). Of note, the resiliency of the individual modules contributes to the greater structural strength of the final building, another advantage of modular construction.

Transportation of the modules depends upon some important factors such as the cost and method of transport, travel distance, and weight. It usually isn’t feasible to ship modules far due to road size and load restrictions. Generally, the maximum desirable distance for transportation of modules is 250 to 400 miles. The costs and transportation difficulties greatly increase for building sites farther than 400 miles.

The maximum width, height, and length of individual modules that can be transported is dependent on several criteria including local Department of Transportation restrictions; bridges, overpasses, utility lines that cross over roadways; and the actual route itself from the factory to the final destination. For ease of transportation, modules commonly have measurements of 15-feet wide, 12-feet high and 60-feet long, although these measurements can differ greatly in any direction based on a number of factors.

inside-modular-process5_800x450

Transporting the finished modules to the jobsite can involve a single truck or many, depending on the size of the project.

Step 4: Erection of modules to form a finished building

Once at the jobsite, the modules are stacked by crane or rolled onto the foundation, bolted together and sealed for weather-proofing. The modules are then connected together, utilities are hooked-up, exterior siding and roofing components are completed, and site work is finished. The final construction stage includes completing exterior systems such as cladding, final caulking and sealing, adding stairs and elevators, and competing any interior elements such as painting, trim, cabinets, countertops, and installation of appliances that didn’t occur in the factory.

Modular construction offers an accelerated schedule for designers and builders and an accelerated ROI for owners. This is primarily accomplished by working on multiple fronts simultaneously. While modules are built and furnished in a controlled offsite location, site work can occur at the same time, eliminating the need for less efficient, strictly linear process.

This process—called parallel construction—is a key benefit of the modular construction process as it allows for reduced construction times of about 30% - 50% that of conventional construction.

inside-modular-process4_800x450

Installing the modules happens quickly. In some cases, large multi-story buildings can be stacked in less than two weeks.

The process of modular construction is strict. Plans must be finalized early and stakeholders must have a complete understanding of the entire building process, but the advantages of modular construction are indisputable. To find a modular builder near you, click here.

More from Modular Advantage

Stacking Up: How Vision Modular is Helping Take Modular Construction to New Heights

VMS’ latest modular project in London’s Canary Wharf, dubbed Marsh Wall, will sit among many of the city’s iconic, high-rise buildings.

Vertical Engineering: Inside the World’s Tallest Modular Building with MJH Structural Engineers’ Michael Hough

“101 George Street has moved modular into the realm of skyscrapers and is achieving recognition alongside some of the world’s most amazing new tall buildings,” says Michael Hough.

Designing for a Sustainable—and Modular—Future

A conversation with Stuart Cameron,
Managing Director and MMC Lead at SCMS Associates/The HIve Group, about the current state of modular and offsite construction in the UK.

The Rapid Rise of Affordable Modular Housing in Canada

Canada’s Rapid Housing Initiative represents a huge success for the modular construction industry, and MBI members are building modular multifamily homes fast. Here are some examples.

Seeing the Potential for Modular Construction in Colombia

Founded in 1983, Constructora Bolivar specializes in the design, construction, project management, and sales of single family and multi-residential homes across the Colombian social strata. Now it’s laying the groundwork for the country’s modular construction industry.

Modular Building Poised for Takeoff Globally

That modular building hasn’t already gained more U.S. market share is a source of bewilderment to many. Though the technology has been around for more than 70 years, modular building in the U.S. has never gained as solid a foothold as it has in other societies. But it’s time may finally be here.

Wilmot Modular: Always Willing to Help Out

Mike Wilmot, president of Wilmot Modular in Maryland, shares his experience responding to natural disasters and explains his company’s Rapid Response Program.

The Quick Response to Hurricane Katrina

Jane Conkin, owner of Quick Buildings Modular, recalls how her company provided much-needed modular buildings after Hurricane Katrina.

In Rough Times, Black Diamond Shines

Black Diamond CEO Trevor Haynes talks about the disasters his company has helped with and how disaster response is more than the “nuts and bolts” of transporting assets.

A Village Inspires a New Modular Emergency Housing Concept

These emergency housing modules, designed by Oregon’s MODS, have been designed so they don’t require highly skilled labor to build them — which opens up employment opportunities for the future residents of the buildings.