Modular construction refers to offsite building construction under controlled factory setting conditions. Unlike a “stick-built” structure that is built piece by piece, modular structures are produced in “modules” or separate sections. Permanent modular buildings and relocatable modular buildings are the main types of modular construction buildings.



Although the modular construction concept has been around for over 100 years, the unique opportunities of modular construction had been largely untapped until the revival of modular solutions, such as modular apartment buildings, modular construction hotels, modular classrooms, and modular office buildings.



The modular construction method uses the same building codes, raw materials, and standards applicable for traditionally built projects. Completed modules are transported to and assembled on site to fit with each other, with the same design intent and architectural specifications of the most advanced site-built facility.



Keep reading to learn more about modular construction.



What is Modular Construction?
The first documented modular construction example is a prefabricated home (the “Manning Portable Cottage”) made in 1830 by a London carpenter named John Manning. Later, the rapid rebuilding of homes and the growing popularity of prefab structures led to the widespread acceptance of the time- and space-saving modular construction method.



Concrete, steel, and wood are commonly used modular construction materials. Modular building manufacturers buy and recycle materials in bulk and maintain portable building and trailer fleets to create cost efficiencies and ensure quick turnaround for projects.



Over the years, modular projects have grown in popularity and are considered suitable to address the challenges of affordable housing, long construction schedules, and the high construction cost of conventional buildings.



Although modular architecture has been considered cheap, repetitive, or unreliable, the surge in modular projects is leading the way toward construction driven by strong and stylish designs available at cost-effective prices.



The modular design is adaptable to various configurations and building styles. For example, the city of New York represents the elegance of modular construction apartments and hotels, focusing on quality and livability.



Another significant driver is the advocacy of the modular industry by associations such as the MBI. Founded in 1983, the Modular Building Institute (MBI) is an international non-profit trade association that supports the modular/offsite construction industry through education and outreach events as well as innovative construction practices.



Are Modular Buildings and Prefabricated Buildings the Same?
Prefabricated construction is a broader term that encompasses modular structure construction and panelized construction. A modular building is a prefabricated building in which prefabricated components are assembled offsite in a factory and later transported to the construction site fully or almost complete.



Interestingly, not all prefabricated buildings are modular buildings because prefab includes pre-made individual pieces or parts of an overall building structure. In contrast, modular buildings are made from separate box-like modules secured together on site.



In recent times, prefabricated construction has gained a lot of attention as a cost-effective and an eco-friendly mode of construction. Prefabrication involves creating prefabricated panels and modules in a factory, away from the construction site.



Modular Buildings vs. Traditional Buildings
A traditional building is an example of on-site construction while a modular building represents offsite or volumetric construction. Compared to traditional construction, modular construction is believed to be more efficient as it saves money and assures the project stakeholders of improved workmanship and reduced financial risk.



Research shows that a modular construction schedule can result in project completion in half the time compared to a traditional method.



With an estimated 60%-90% of the work completed in a factory-controlled environment, a modular building is ready either as a complete structure or as a set of modular subassemblies for a larger project.



However, the traditional method or linear construction requires every step to be completed before the next step, which increases the time taken to occupy a building.



Moreover, inconsistent labor yield and weather conditions can affect the quality of construction that largely occurs on the site. Do traditional construction methods have an advantage over modular construction? Yes.



A modular project is not flexible for late changes in design and may need early client sign-off unlike an on-site project.



Modular Building Design
The modular sections are configured to match the building layout and maintain ease of transportation. As individual modular building components cannot be easily realigned onsite, modular construction architecture demands the inclusion of specific construction techniques and design practices.



Modular building design involves critical components, such as:

Advanced building information modeling (BIM) to assess energy performance and cost-effective measures
Computer-aided design (CAD), additive manufacturing (3D printing), and manufacturing control systems for modular component alignment
Design for Manufacture and Assembly (DfMA) practices to control assembly tolerances and misalignment


Modular construction software eliminates manufacturing errors and seamlessly integrates project information, including cutting lists, material reports, and shop drawings for quicker project completion.



Modular Construction Types
Generally, a modular construction system consists of many FRP (fiber-reinforced plastic) composite panels bonded together to form a membrane structure with complete structural integrity.



A modular manufacturer provides a wide range of residential, commercial, and industrial modular units in compliance with building codes like the International Building Code (IBC) and a variety of floor plan layouts.



Here are the main types of modular construction buildings:

Permanent Modular Construction (PMC)
Permanent modular construction (PMC) uses offsite, lean manufacturing techniques to prefabricate single or multi-story buildings in deliverable modules. Integrating PMC modules into site-built projects or as a stand-alone turnkey solution provides higher quality control and reduces waste unlike projects that leverage only site-built construction.



Permanent modular buildings are also ideal for mixed-use applications. It is possible to integrate a PMC building with a concrete tilt-wall or a pre-engineered steel building to yield a hybrid facility.



Relocatable Building (RB)
A Relocatable Building (RB) is built using a modular construction process and is partially or completely assembled for reusing multiple times and transporting to different building sites.



An RB meets the need for a temporary space and complies with the manufacturer’s installation guidelines, local building code requirements, or state regulations. In addition, the versatility of an RB makes it a good option for emergency and natural disaster relief services.



When there is a need for a fast, temporary space solution, an RB works well with complete MEP (Mechanical, Electrical, and Plumbing), fixtures, and finishes. Relocatable modular buildings are ideal for construction site offices, medical clinics, sales centers, restroom facilities, schools, etc.



Relocatable buildings offer a variety of benefits, including:

Ease of relocation
Fast delivery
Greater flexibility
Low-cost reconfiguration
Accelerated depreciation schedules


Apart from the types mentioned above, an in-depth analysis of modular construction identifies the following categories based on the modular construction method:

Closed modular construction
Closed construction involves designing, developing, and constructing entire rooms offsite, including electrical wiring, plumbing, and HVAC. This prefabrication process installs and “closes up” all components at the manufacturing facility before delivering the completed module at the job site.



Open modular construction
Open construction introduces more versatility and simplifies the inspection process because the building components can be expanded, downsized, relocated, and visually inspected at the jobsite while maintaining quality and engineering integrity.



With respect to modular construction, it is important to mention key modular building variations that are widely used worldwide. These are modular trailers, modular containers, panel-assembled office systems, and office complexes.



Now, let us look at modular construction pros and cons and major applications.



Modular Construction Advantages
Working on the modular structure offsite and simultaneously preparing the site reduce the lead time required for project completion.



Here are some well-known benefits of modular construction:

Faster, greener, and safer construction
The primary benefits of modular construction are speeding up construction time and keeping the project on schedule by providing significant time savings (around 30%-60%).



Unlike the high volume of waste generated by a regular construction site, a modular manufacturing facility uses engineered construction materials and in-plant recycling to provide an environmentally friendly construction process that minimizes waste and optimizes recycling.



Modular construction provides safe working conditions during production and assembly to workers and tradespeople. In addition, storing materials and building modules in a factory help keep construction sites clean and prevent theft concerns.



Lower construction costs
The cost of a modular construction project depends on several factors, such as design complexity, the scale of the project, the types of materials, and the inclusion of internal fixtures and fittings. Modular options provide the advantages of less labor, fewer materials, shorter construction times and more. Contrary to site-built projects, modular projects’ improved overall costs minimize cost overruns.



Less waste and more savings
According to the UK-based climate action NGO named “WRAP” (Waste and Resources Action Programme), a modular building equates to an estimated 90% reduction in material use compared to a traditional build.



By limiting the amount of waste on projects and using precise modeling through modular construction techniques, the modular construction industry is contributing to a greener world and an improved construction industry.



Adaptability to remote locations
Whether you need a state-of-the-art biotechnology facility or a utility system module, modular construction manufacturers provide a broad range of modular construction solutions for use in remote locations and extreme weather conditions.



Better structural strength
In contrast to conventional construction, the module-to-module combination of units greatly increases the structural strength of a modular unit. Furthermore, stricter quality control over assembly lines has enabled modular manufacturers to ensure consistent quality in the manufacturing process.



Better thermal insulation and damp resistance
Due to little air infiltration of a modular unit such as a modular home, it reduces heat loss considerably and ensures greater energy efficiency. As building supplies are stored in on-site warehouses, there is virtually no risk of using wet materials in building a modular unit.



No weather-related delays
Climate-controlled factory production eliminates weather-related construction delays. As modular construction continues offsite regardless of the weather conditions, it is easy to complete the project on time without waiting for onsite construction activities.



Modular Construction Disadvantages
While there are various benefits of modular construction, there are certain disadvantages, such as:

Costly transportation
The cost of transporting modules from a factory to a construction site is higher, with inherent risks in transporting large loads of modules. Costly transportation is the main disadvantage of modular construction.



Complicated approval process
Modular building approval may require additional inspections for local and state building codes. The complicated approval process may adversely impact the project timeline.



Design updates
While design updates can be made for a traditional build during construction, it is not easy to make updates to pre-built modules once they leave a modular manufacturing facility.



Permit issues
The process of issuing permits varies from state to state. For example, state-level permits for module interiors may be rejected at other locations.



Reduced resell value
Modular buildings still face a stigma surrounding the quality of the properties. It will take time to see a change in the opinion that the quality of a modular property is not inferior to that of a traditionally built property.



Site and size constraints
While modules are generally restricted to certain maximum dimensions, it is difficult to transport modules in trucks with varying capability and size. Moreover, an irregularly shaped building site may pose design challenges for rectangularly shaped modules that are the norm in modular construction.



Applications of Modular Building Systems
Permanent and temporary modular building systems are available in attractive sizes, specifications, and styles. For example, a general contractor may offer modular residential construction services for custom-built homes—a factory-designed-and-built modular home that has the flexibility of high-quality construction with wholesale pricing.



The notable applications of residential and commercial modular construction include:

Cashier booths
College dormitories
Community health clinics
Diagnostic imaging centers
Distribution centers
Equipment booths
Mobile office trailers
Multi-story office buildings
Parking booths
Pharmaceutical labs
Portable classrooms
Portable restrooms
Retail shops and malls
Screening booths
Single-family homes
Sports facilities


Wrapping Up
Modular construction is an efficient construction process that generates less waste and allows for greater precision in component fabrication. Many architects, owners, contractors, and developers are leveraging modular building systems for faster, safer, higher quality, and less disruptive construction without sacrificing the aesthetic appeal.



A modular structure combines modern design and smart engineering for a pleasant and a professional space. In the future, industry experts expect a boom in the modular construction market that will cater to the unique needs of residential, commercial, and industrial customers.



Unlike modular structures in the earlier days, modern modular buildings now include essential features such as handicap accessibility, digital technology compatibility, high-performance HVAC systems, dimmable LED lighting, occupancy sensors and more.



When you need the best value and the highest quality in the shortest project timeline, think modular for your construction project!



From modular medical buildings and modular offices to portable buildings and portable classrooms, modular construction has transformed the construction industry in multiple ways. With the beauty and benefits provided by modular construction, you can choose a modular construction project that is right for your budget, project type, and location.



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