Corbel vs. Cantilever — What's the Difference?

Corbel and cantilever are both architectural terms describing elements that project from a wall, but they differ significantly in structure and engineering. A corbel is an architectural feature where successive layers of material are extended slightly beyond the one below, creating a stepped appearance. This method has been used since ancient times for supporting projections or overhangs. In contrast, a cantilever is a structural element that extends horizontally and is supported at only one end, with the other end projecting into space without any external bracing.

Corbelling creates a form of support that distributes weight back into the wall or structure from which it projects. This technique allows for the creation of balconies, beams, and arches using materials like stone, brick, or wood, building up layers to achieve the desired projection. Cantilevered structures, however, rely on the strength of the material and the integrity of the support at the single point of connection. Modern examples include large balconies, bridges, and even buildings where part of the structure extends into open space, supported without visible means at its far end.

The design and aesthetic of corbelled elements often contribute to the architectural style and detail of a building, adding decorative as well as functional features. Cantilevers, meanwhile, are celebrated for their engineering and the dramatic visual effect they create, seemingly defying gravity. They are particularly prominent in modern architecture, where the use of steel and reinforced concrete has enabled more ambitious cantilevered designs.

In terms of structural engineering, corbels distribute loads vertically and require careful construction to ensure stability and weight distribution. Cantilevered structures, on the other hand, must account for torsion, bending, and shear forces, requiring detailed analysis to prevent failure. The use of cantilevers is often a showcase of engineering prowess, highlighting the balance between form and function.

The choice between corbelling and cantilevering depends on the architectural requirements, aesthetic goals, and structural considerations of a project. While corbelling is suited to traditional or historical reproductions, requiring minimal extensions and using specific materials, cantilevering offers a modern approach with greater flexibility in design and the potential for significant horizontal extension.