We’re of the opinion that it shouldn’t take a PhD in construction to understand the world of “off-site” (or “prefab”) construction. Industry websites tend to be very jargon-heavy, so a quick internet search may make you feel overwhelmed. Instead of a lengthy explanation filled with confusing language, here’s our take on off-site construction for the everyday homebuyer.
Site-Built vs. Off-Site Construction
Let’s start by breaking down the difference between site-built construction and off-site construction. Site-built construction is probably what comes to mind when you think of how homes are built. It means that the raw materials for the home (lumber, drywall, insulation, etc.) are sent to the site, and the builder uses those materials to construct the home right there. Homes have been built this way for hundreds of years. But when a better way to build comes along, it makes sense to explore it — and that’s where off-site construction comes in to play.
With off-site construction, raw materials are sent to a climate-controlled factory and are used to build the wall and roof components. The fabrication process is very similar to how homes are built on-site — just more efficient and under a roof. Once manufacturing is done at the factory (with doors, insulation, and windows installed) the components of the home are transported to the site and assembled to form a permanent structure on a traditional foundation.
Why Off-Site Construction?
So, then why choose off-site construction? There’s a reason that your car, smartphone, and shoes aren’t built outside in the elements. Off-site construction allows for a superior product There’s better quality control and a more regulated work environment. Another huge advantage is that work in the factory can happen at the same time as the work being done on sight, which makes for a shorter construction time.
The extent of exactly what is built in a factory may vary based on the size of the home, the type of construction, the distance from the factory, and ultimately the homebuilder’s preference. Like any other build, prefab builds must comply with city, state, and federal building codes and undergo inspections. Coupled with factory precision and protection from outdoor elements, this actually results in a higher quality of build than with a site-built home.
Two Types Of Off-Site Construction Methods:
1. Panelized Construction
In panelized construction, the walls, roof, and floor of the building are constructed in a factory-controlled environment and delivered to site. The doors and windows come pre-installed in the walls, but all the other finishes are applied on site. This includes drywall, painting, floor coverings, tiles, cabinets, countertops, etc.
For a site that has a few more obstacles, panelized is more nimble. The trucks used to carry wall and roof panels are generally smaller, they can navigate tighter city streets, and the whole process is better suited for smaller or less open spaces.
2. Modular Construction
Modular homes are built as separate boxes, with pre-assembled walls, floors, ceilings, plumbing/electrical fixtures and completed bathrooms. They are then assembled and set on a foundation. These boxes are 80% to 90% complete when they arrive on site, so they require significantly less on-site work than panelized homes.
Modular construction is ideal when there’s easy access to the site (i.e. no real obstructions for getting a large truck to a site) and minimal overhead obstructions for a crane to lift and place modules. It’s also a good fit when on-site labor is limited or expensive, or when conditions are tougher.
Module uses both panelized and modular construction depending on the factors mentioned above. Have any questions about off-site construction or any other parts of the process? Email us at info@modulehousing.com