Prefabricated wood building systems

Wood prefabrication as a kit-of-parts 

Prefabricated wood building kits are made up of prefabricated components delivered and assembled on site, much like life-sized Lego. This is most often achieved using prefabricated panels that can form entire sections of a building such as roofing components or structure (ceiling, decking and beams), building structure (wall panels, beams, columns and shear panelling) and even glazing packages (walls with built in windows and entrances). Panels can be open—that is a preassembled wall that is later fitted with insulation, weather barriers and cladding—or closed, such as a total preassembled wall panel complete with windows, doors, plumbing, electrical and finishes.

Brock Commons Tallwood House, UBC
Photo credit: KK Law

Building systems used in prefabricated wood construction

Prefabricated wood systems are made from either conventional light-frame construction or mass timber systems, and finished construction often involves a mix of both.

Light-Frame

Conventional light-frame wood construction—when dimension lumber and materials are delivered to site and then cut and installed according to a prescribed blueprint—still makes up the bulk of construction. Typical light-frame construction is built of repetitive wood framing to form rafters or trusses using standard dimension lumber. Oriented strand board (OSB) and plywood form roof decking, floors and walls. This same construction can be completed in a controlled environment, built as nearly completed modules—with plumbing and finishes—that can then be delivered to site for installation.

Mass Timber

Mass timber products are thick, compressed layers of wood that serve as the load-bearing structure of a building. Because these products are lighter than other construction materials, they lend themselves well for prefabricated wood building systems allowing a speedier and more efficient process. Cross-laminated timber (CLT) is a popular mass-timber product because of its versatility. CLT is used to build floors, walls, elevator shafts, and roofs. Glue-laminated timber (glulam) is often used as headers, beams, columns, trusses, or in load-bearing arches. There are several other engineered wood products used in prefabrication, including nail-laminated timber (NLT), dowel-laminated timber (DLT); laminated strand lumber (LSL); laminated veneer lumber (LVL); and parallel strand lumber (PSL).

BC Passive House Factory, Pemberton
Photo credit: Ema Peter Photography

How prefabricated wood construction can make housing more flexible and versatile

Prefabricated wood modules can be assembled and disassembled, modified or relocated making it well-suited to the rising demand for flexible housing, a trend that is giving residents the ability to change the size and composition of a home over time, boosting affordability and value. Modular wood construction is an ideal material for flexible systems such as interior walls that can easily be reconfigured to expand or shrink the size of a dwelling depending on the occupants’ needs. Smaller units could be combined when a family has children, or a three-bedroom unit could be split up when a child leaves for college.

Abbotsford supporting housing
Photo credit: Metric Modular