Prefab

Prefabrication, or prefab, refers to construction components manufactured off-site in a controlled factory environment and transported to the building site for final assembly. Prefab can involve panels, modules, or other sub assemblies and is used to improve efficiency, quality, and predictability in construction.

The concept dates back to early industrial building practices and gained widespread use in the 20th century with mass-produced housing and modular projects. Advances in materials, transportation, and digital design have broadened its applications and performance.

Common prefab methods include panelized systems, where wall, floor, or roof panels are manufactured off-site; modular or volumetric construction, in which large units such as rooms or cores are produced as self-contained modules; and precast concrete elements. Wood-based systems, such as cross-laminated timber, and steel components are also used.

Advantages typically cited include faster construction timelines, reduced on-site labor, less waste, safer working conditions, and improved quality control. Disadvantages can include higher up-front design and logistics costs, transport and crane requirements, constraints on site layout and utilities, and potential regulatory or permitting delays.

Prefab is used in residential, hotel, healthcare, and educational projects, among others, and often relies on Building Information Modeling to coordinate components. When well designed and standardized, it can shorten schedules and reduce environmental impact, though it does not eliminate design challenges or the need for skilled installation.