What is Off-site Construction?
Off-site construction involves the process of planning, designing, building, transporting and assembling building components for fast building site assembly and to a higher degree of finish than is typical with traditional on-site construction. Off-site construction consist of building homes and commercial projects using some form of a building system for the construction process.
Types of Building Systems
The National Association of Home Builders recognizes four types of construction using building systems:
Concrete Home Construction
Concrete panel and form construction is becoming a more popular options for residential home construction
Log & Timber Home Construction
Log home owners are like Harley owners, they are looking for a specific look and feel from their new home.
Panelized Home Construction
Panelized homes are considered a high performance building system that is an inherently green product.
Modular Home Construction
Modular construction is a home building system where 75-85% of the home is delivered complete.
Concrete Home Building
Most think of concrete construction for commercial buildings. However, there has been a growing interest and use of concrete for residential construction.
There are several methods to utilize concrete. A popular one for residential construction is panel systems. The panels are typically precast and then placed with a crane. These are precast panels that are cast/made offsite at a manufacturing facility and then trucked to the site for installation. Removable forms are what most think of for foundations. However, when casting above grade, foam insulation is typically placed in the forms before pouring begins. This results in a solid wall with high thermal mass. This method still requires that all trades still participate fully in the onsite completion process.
Log and Timber Home Building
Log and timber home building has been around for hundreds of years. The process of harvesting and drying the logs and timber have improved over the years.
Methods to seal areas between logs and at mating areas of roofs and walls have improved. However, log home owners are like Harley owners, they are looking for a specific feeling from the product and not everyone is looking for that. Log and timber homes are a part of the building systems industry and will continue to thrive as a niche building system. Modular construction offers the ability to mimic the log home look and feel with higher energy efficiency and at a lower cost to the home buyer.
Panelized Home Building
Within panelized home building there are several subcategories. Two of the main ones being basic panelized construction and another one known as Structural Insulated Panels (SIPS).
Using basic panels, a home plan is divided into wall and roof sections and are framed off site in a factory. The panels are then loaded flat on large trucks and delivered to the site. Each panel is coded and the entire home is assembled, much like a puzzle with the coded pieces. However, the panels typically do not contain plumbing, electrical wiring, and finished interiors or exteriors. This requires all of the onsite completion by trades as is typical with traditional onsite construction. SIPS are considered a high performance building system that consists of an insulating foam core that is sandwiched between two structural facings. These facings can be OSB, fiber-cement board, etc.
SIPS are considered one of the most airtight and well insulated building systems making them an inherently green product. With SIPS, the plumbing, wiring, and interior/exterior finishes have to be completed onsite as is typical with traditional construction.
Modular Home Building
Modular construction consists of many modular subassemblies built and assembled in an environmentally controlled factory that are assembled into a larger component, or module. That module is then shipped to a building site, combined with other modules, and assembled into a finished product.
Today there is a major labor shortage in the building industry. Quality labor is just hard to find.
The best subcontractors that are out there, because of supply and demand, are raising their prices thereby increasing the cost of new home construction. Using the modular building system allows a builder to control his costs by having much of the home built in the factory. The plumbing, electrical, mechanical, and many of the interior/exterior finishes are completed in a factory. This reduces the need for dependence on expensive onsite labor.
Most homes built using modular construction are delivered to the site 75-85% complete. The impacts of weather as a factor in home construction is virtually eliminated. By keeping rain and moisture out of the home during construction, a healthy living environment is promoted by keeping floors and walls dry during construction, unlike with traditional site built homes. This reduces the risk of mold and mildew growth.
DO MORE WITH MODULAR
Across the range of off-site construction methods, modular is the one that is the most complete from the factory – up to 85% in some cases. It is shipped and assembled as 3D volumetric units that are service or structural units to be joined on-site.