precast

Precast refers to building components that are cast in a factory-controlled environment and transported to the construction site for installation. The elements are formed in molds, cured, finished, and then delivered to site where they are assembled. While many precast elements use concrete, precast can involve other materials, though precast concrete is by far the most common.

Common precast elements include structural members such as beams, columns, floor slabs, and hollow-core units, as well as wall panels, stairs, and architectural components like decorative façade panels. In structural practice, precast concrete may be prestressed (pre-tensioned or post-tensioned) to increase span and load capacity. Precast elements are manufactured to tight tolerances and can incorporate integrated joints, openings, and connection features for efficient on-site assembly.

Manufacturing occurs in factories with formal quality-control procedures. After casting and curing, elements are transported to the site and connected through grouted joints, steel couplers, or post-tensioning systems. Connections are designed to resist movement, weather exposure, and seismic or wind demands, and may require temporary works such as cranes during installation.

The main advantages of precast construction include faster on-site erection, improved quality control, reduced weather risk, and potential labor savings. Drawbacks can include higher transportation costs, dependence on craneage, longer fabrication lead times, and the need for careful design coordination among architects, engineers, and fabricators.

Precast is widely used in commercial, residential, industrial, and infrastructure projects worldwide. Design and fabrication typically follow established codes and standards in each jurisdiction, such as ACI, Eurocode, or national equivalents.