Introduction to Prefab and Modular Homes

Building a new home can be a rewarding process, especially if you are well-prepared. The information we’ve gathered here will help you to get started in the direction that’s best for your project. Prefab and Modular homes are positive options that are well worth your consideration, with a number of different advantages and disadvantages depending upon your needs.

As you begin your research into building a new home, you’ll soon find that there are a variety of options available. Even if you’ve been through the homebuilding process before, you’ll want to familiarize yourself with the latest trends and innovations. Determining the process that best suits the needs of you and your family requires careful consideration of many factors, including the building site, the design program and your goals. This introductory guide will explain the differences between several popular construction options, and help you to understand the pros and cons.

Conventional Construction

Most new homes are built using conventional construction methods – also known as site-built, because most of the work is done on site. Building materials are delivered piecemeal to the jobsite, typically from a lumberyard. These raw materials – framing lumber, plywood, insulation, etc. – are then individually measured, cut and fastened together on site to build the home. Although the principles of conventional homebuilding have remained largely unchanged over the past hundred years, this is still the most common method for building new homes.

A conventional home construction job site

Prefabricated Homes

Unlike conventionally-built homes, prefabricated homes – also known as prefab – are manufactured using off-site construction methods. Significant portions of the home are built off-site, typically in a factory environment. These factory-built components are then shipped to the building site for final assembly.

Within the realm of prefabricated homes, there are several different approaches that vary significantly in the methods used:

Modular Homes

Modular home construction is based on building large, three-dimensional boxes – the “modules” – in the factory. Each module consists of a floor, walls and ceiling that are preassembled in the manufacturing facility. Some interior and exterior finishes may be preinstalled on the module. These modules are then delivered to the jobsite, typically one per truck, and installed on a full concrete foundation using a large crane. For a small home, all of the modules may be set in a single day. Setting the modules for a larger home might require multiple days. After the modules are set, the home may be anywhere from 50% to 90% complete, depending on how finished the modules are when they leave the factory. The remaining finish work is done on site. While the design of a modular home has to take into account the dimensions, engineering and configuration of the individual boxes, this system can generally accommodate a wide variety of architectural styles.

Panelized Homes

Panelized homes are an increasingly-common form of prefabricated home. This approach is based on prefabricating two-dimensional floor, wall and roof panels in a factory setting. Some manufacturers preinstall the windows and doors in the factory, and they may also insulate the panels. The panels are then flat-packed in bundles, delivered by truck to the site, and assembled using a crane. One other difference between modular and panelized homes is the size of the trucks needed to deliver, and the cranes needed to unload. Flat-packed bundles are typically easier to work with than full-size modules. Assembling the panels into the shell of the home might take one to two weeks, at which point the project is approximately 40% to 50% complete. Exterior finishes such as roofing and siding are then installed, and the interior work is completed similarly to conventional construction. Panelized construction generally offers more design flexibility than modular construction.

Unity Homes panel production facility

Kit Homes

Although kit homes may be considered a type of prefab home, the level of prefabrication is generally lower than for modular or panelized homes. Kit home manufacturers deliver all of the parts and pieces of the home to the site, where they are assembled using conventional methods. The kits vary in the extent to which the individual parts are precut to size. Kit homes are popular with owner-builders, who may be able to reduce costs by doing much of the on-site assembly work themselves. One of the main precursors to today’s kit homes was the Sears & Roebuck “catalog home,” of which about 75,000 were built in the first half of the last century.

Manufactured Housing

Manufactured homes, which are also called mobile homes, are built entirely in a factory, typically on a base of steel beams. The entire home is then shipped by truck to the site, and placed on masonry blocks, metal stands or a concrete foundation. The materials and methods used to build manufactured homes generally result in costs that are considerably lower than for other types of prefab, and for conventionally-built homes.

Comparing Prefab and Conventional Home Construction

How does prefabrication stack up against conventional home construction? Both methods have pros and cons, but as the advantages of prefabrication are becoming more widely appreciated, this method of construction is growing increasingly popular.

Quality – High quality homes can be built using any type of construction. Ultimately it’s the design, the engineering, the materials, and the craftsmanship that determine the quality of the home. Prefabricating the components of a home in the controlled conditions of a factory allows for greater precision and quality control than is achievable when building entirely on site. In the factory materials are protected from the elements, processes are efficient, and the workers tend to be well-trained.

Sustainability – The prefabrication process generates considerably less waste than conventional construction, and the materials can be more easily vetted for sustainability.

Streamlining – The factory setting allows for much of the construction to be done in a streamlined manner using state-of-the-art manufacturing techniques and computer-controlled machinery.

Speed – Prefabrication generally results in accelerated construction schedules, because while the site work and foundation are being installed on site, the components of the house can be built in the factory. The weather tight shell of the home is then assembled on site in a matter of days, potentially shaving months off of the project schedule.

Other possible advantages: Depending upon the methods and technology used to build a prefabricated home it’s quite possible that you will also experience lower construction costs, lower utility bills, healthier indoor air quality, and more comfort. When looking at your options, be sure to consider some of the long-term benefits that could work to your advantage for years to come.

Offsite precision window installation at Unity Homes pre-production facility

The Local Builder

While much of the work on a prefabricated home is done in the factory, some amount of preparation and finishing will still need to be done on site. That’s where the local builder comes in. The local builder oversees the site work and the installation of the foundation. The builder also typically handles the subcontractor coordination and finish work required after the shell of the home has been assembled on site. While it may be helpful to work with a builder having prior experience with prefab, qualities such as good communication, quality craftsmanship and strong references are generally more important.

Next Steps

Because a new home is the largest investment that most people will ever make, we suggest exploring all of the options early in the planning process. We hope we’ve been able to provide helpful context for understanding the various construction methods that are available. If you’d like to learn more about Unity’s state-of-the-art prefabrication process for building homes that are healthy, comfortable, energy efficient and low-maintenance, please reach out to us and we’d be happy to continue the conversation.

Do you have other questions that we haven’t answered here? Reach out to us and we’ll do our best to answer them!

Unity is Redefining Prefab Homes

Unity is a design-build company with an innovative, well-developed process that results in predictably high-quality results for our clients. Unity clients benefit from our experience, credibility, and knowledge. Our use of cutting-edge technology, automation, and teamwork allows us to build healthy, comfortable, energy-efficient homes.

Unity’s Better Way to Build is based on a unique design system, off-site construction and on-site assembly. Much of the work on each home is done by computer-controlled (CNC) machines in our state-of-the-art panel production facility in Keene, NH. But the people operating the equipment and the highly-evolved processes that we’ve developed to manage the work are just as important as the machines themselves.

 Learn more about how Unity prefabricates homes with superior quality and energy efficiency.

A completed Unity Home

Unity is a New Hampshire-based home building and design company that combines modern technology and traditional craftsmanship to produce high quality panelized homes. We design and build prefab homes for the greater New England area including New York, New Jersey and beyond.