Offsite construction for housing isn’t new. Rather, it’s an evolutionary path that builders have been walking down for a couple of hundred years. And because most of the products created at each step of that evolution are still available, builders can get on the path with any one of them.
For instance, modular bungalows were available in the early 19th century. Henry Manning, a London carpenter, produced the Portable Cottage in 1837 for export to Australia. The California Gold Rush of 1848 saw imports of prefabricated houses from Britain, Sweden and China arrive to house the ‘49ers.
But it’s a huge leap from site building stick-by-stick to delivering volumetric units with everything mostly complete. Some builders are willing to take this leap, but a larger percentage might be more comfortable starting with components.
Of course, all builders already use components to some degree. That’s because the strict definition of the term includes manufactured elements like windows, doors and kitchen cabinets. (In the 1800s, windows and doors were built on-site. Today, that sounds crazy!)
What most builders think of as components are actually structural components, things like roof trusses, floor trusses and wall panels. While everyone is familiar with these, adoption tends to vary by region, at least in the US. In the Northeast/Mid-Atlantic, production builders have used roof trusses, wall panels and floor trusses for 50+ years. In the South and Southeast, many haven’t used them, and some would never think of doing so.
But the adoption of building systems must start somewhere, and structural components offer low risk, along with measurable benefits in terms of speed, quality and consistency. For instance, the invention of the roof truss saved time, saved money and built a stronger roof. If you can do that with roofs, why not do it with walls? If you can do it with walls, why not switch from solid joists to floor trusses? And why not take the floor trusses and connect them together with OSB to create floor cassettes that are shipped to the jobsite?
This evolutionary process can also extend to energy efficiency, with the use of structural insulated panels, or SIPs, to build whole houses, including walls, floors and roofs.
Some manufacturers have actually evolved their framed panels. Check out our article this month on Unity Homes, whose closed panels include insulation, wire chases, doors and windows. Pre-installing these elements at the factory shortens the time needed to assemble and finish the home on-site.
What about foundations? Those can also be offsite-fabricated, and include insulated concrete forms (ICFs) and precast wall systems from companies like Superior Walls.
As you can see, the cost savings, time savings and quality improvements made possible by components can really add up. But these savings aren’t limited to site building. Modular manufacturers can also use floor cassettes, wall panels and prefabricated roof systems to reduce the time and expense needed to create volumetric boxes, with all of the finishes applied in the factory.
The point here is that the nature of offsite means it always changes the status quo. A lot of people are comfortable with the status quo, but it’s not sustainable any longer. Something has got to give.
You can jump onto the evolutionary path of offsite construction at any point you want by using trusses, panels, SIPs, floor cassettes, or volumetric modules. At the very least, I think there’s an opportunity for all builders to start using structural components that will reduce costs, increase speed and increase quality. It’s time to pick your offsite solution. Where will you start?
If you liked this article, you can follow Ken Semler on LinkedIn, where he offers daily insights and commentary about offsite construction.
