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Prefab vs. Modular Construction [A Complete Comparison]

prefab vs modular construction

What’s the Difference Between Modular Construction and Prefabrication?

Prefab and modular construction have gained significant attention as a result of skyrocketing construction costs and labor shortages, but there’s a misconception that prefab vs. modular construction is a strictly “either/or” choice. The real question is: Do you want a more traditional build with prefabricated elements, or should you go fully prefab modular?

Let’s explore the key similarities and differences between prefab and modular construction so you can make an informed decision for your project.

Table of Contents
Prefabricated Construction: Definition, Benefits, and Uses
Modular Construction: Definition, Benefits, and Uses
The Difference Between Prefab and Modular Construction: Side-by-Side Comparison
Prefab vs. Modular: How to Choose for Your Project
Cutting-Edge Modular, Prefab Multi-Family Homes and Villages

Prefabricated Construction: Definition, Benefits, and Uses

Prefabricated construction, or “prefab,” is when some of the individual building elements, like walls, stairs, floors, or roofs, are made off-site in a factory. The pre-made pieces and components are then transported to the construction site and put onto the building. 

Prefab methods are typically used in conjunction with traditional on-site (stick-built by hand) construction methods. For example, a prefabricated roof may be installed on an otherwise traditional construction project to save some time.

Prefabricated construction components are most commonly made to be used on traditional, by-hand construction projects. Pre-building pieces of the building can save some time and money.

Some of the benefits of using prefabricated elements on traditional, site-built construction projects include:

  • Reduction in time-on-site, which helps avoid concerns like weather delays.
  • When manufactured using robot-assisted automation methods, it can reduce the need for human labor, which is beneficial in current labor shortages.
  • Reduction in error and waste due to standardized manufactured components, saving valuable time and money.
  • Consistency in the product, which is essential for off-site components to be installed on-site without error or deviation.

Modular Construction: Definition, Benefits, and Uses

Modular construction involves prefabricating entire modules (sometimes called building blocks or pods) in a controlled, off-site factory environment. The completed modules are then transported to the construction site, where they’re assembled to form the final structure. 

Some modular companies produce half-built modules that must be finished on-site, while Quantum Assembly produces fully-built, ready-to-assemble modules that snap together on-site in a matter of days.

Prefabricated modular construction is best used for standardized projects that you want to be easily repeatable, like multi-family housing or planned communities. It’s a fast, affordable method for sites that are difficult to access. This makes it an ideal solution for projects like workforce housing and affordable housing for underserved communities.

In addition to all the previously listed benefits of prefab, the extra benefits of prefab modular construction include:

  • Significant reduction in time-to-occupancy because the modules are prefabricated and ready to be shipped and assembled on-site.
  • Significant reduction in total construction costs because the modules are predesigned, prebuilt, and require less labor and fewer materials.
  • The ability to build on sites that are difficult to construct on-site.
  • Standardized modules and floorplans allow developers to choose from predesigned options, which can be arranged in the desired combination of layouts.

The Difference Between Prefab and Modular Construction: Side-by-Side Comparison

First, let’s clear up the “prefab vs. modular” misconception: Modular construction is prefab — the entire module is prefabricated off-site. All modular is prefab, but not all prefab is modular.

So the real difference between modular construction and prefabrication is that, in modular construction, the prefab element is the entire module. In traditional on-site construction, the prefab elements are just a few pieces of the structure, not the whole thing.

To further highlight the difference between prefabrication and modular construction (and their many similarities), let’s compare these six factors:

Manufacturing location

Modular: Entire modules are built in a factory setting.

Prefab: Individual components are manufactured off-site.

Both options lean heavily on off-site construction and manufacturing methods. But the key difference is that with modular, full modules are manufactured off-site and then shipped on-site for assembly. Prefab alone requires more on-site assembly because it’s often paired with traditional construction methods.

Assembly process

Modular: Pre-built modules (sometimes called pods or blocks) are transported and assembled on-site to form the final structure.

Prefab: Pre-built components are added on-site to the structure.

Think of it like LEGOs: Prefab is like building a structure from a bucket of mixed LEGO pieces, while modular is like building LEGO kits and then putting the completed kits together to form the structure.

Customization options

Modular: Limited customization options due to standardized module designs.

Prefab: Limited customization options due to standardized components.

The ability to customize the project is not a strength of either of these construction methods. Modular and prefab are intended to be easily repeatable, using standardization to reduce cost, time, and error. If your intended project is an architecturally and artistically complex design, you may need to construct it using traditional, hand-built methods.

Design flexibility

Modular: Some flexibility in the arrangement and selection of standardized floor plans.

Prefab: Design options are more constrained due to standardized components.

Again, neither option is a good fit for projects requiring significant design flexibility, like single-family homes and one-off projects. Modular and prefab are best used for standardized projects, although there is often some flexibility in how each structure’s premade modules and components are arranged.

Cost considerations

Modular: Typically cheaper than a traditional build, and using prefab elements can help reduce costs even further.

Prefab: Typically used to help save some money on traditional builds.

Prefab and modular are both intended to help you reduce costs by reducing time on-site, labor needs, error, and waste. This is done by standardizing, streamlining, and automating the off-site manufacturing processes as much as possible.

Time and efficiency comparisons

Modular: Quicker overall construction time due to parallel manufacturing and on-site assembly.

Prefab: Reduces construction time on traditional builds, but still slower than fully modular construction.

While using prefabricated elements on a traditional build can save time and increase efficiency, going fully modular is by far the fastest and most efficient build method. For example, Quantum Assembly’s prefabricated modular buildings can go from an empty site to a move-in-ready structure in weeks.

Prefab vs. Modular: How to Choose for Your Project

As outlined above, it’s rarely a “modular construction vs. prefab,” “either/or” situation. Developers don’t typically choose between modular vs. prefab — instead, they decide how much prefabrication they plan to use on their project. Modular construction is entirely prefab, whereas prefabricated elements can be used on a hand-built, site-built project — just to a much lesser extent. 

When choosing how you’ll build your project, consider these five factors:

  • Project scope and requirements
  • Budget constraints
  • Timeline and project schedule
  • Design and customization needs
  • Transportation and site accessibility

For example, if your project is a one-off, custom design, a hand-built traditional construction method is probably better. But you may still be able to use some prefabricated components.

If, however, you want to develop multi-family buildings or planned communities using standardized designs that reduce time, money, and labor requirements, then prefab modular construction is the way to go. This off-site, pre-made construction method is especially ideal if you’re developing in an area that makes on-site construction difficult.

Cutting-Edge Modular, Prefab Multi-Family Homes and Villages

Quantum Assembly has taken the basic ideas of prefabricated modular construction and solved the issues that “traditional modular” has struggled with for years. By reinventing the materials used in modular so that they’re better suited to the processes of prefabrication, Quantum Assembly has developed a new type of prefab modular — faster, stronger, better buildings that no longer require wood, drywall, or paint.

Contact a representative now to learn more about Quantum Assembly’s prefabricated multi-family homes and developments and to order sustainable, attainable, and curated buildings and villages.

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