Corbelling

Corbelling is a masonry technique in which successive courses of stone or brick project beyond the one below, creating a stepped profile that can form a supporting framework above openings or for ceilings. By transferring the weight of upper elements outward and downward, corbelling allows construction without a full arch.

Two common forms are the corbel arch and the corbel vault. In a corbel arch, successive courses protrude inward until their edges meet near the opening, producing the impression of an arch without true voussoirs. A corbel vault uses the same principle to create a vaulted ceiling or roof; when the courses converge, the interior becomes a hollow space. Corbels can also serve as decorative or cantilevered features that overhang without forming a complete vault.

Corbelling appears in multiple ancient cultures, from Mesopotamian temples and Egyptian monuments to Mycenaean and Neolithic European structures. Notable examples include the beehive tombs and the Treasury of Atreus at Mycenae, where the dome is formed by successive corbels; the corbelled roofs of Newgrange in Ireland; and early ziggurats where upper platforms overhang the lower courses.

In later periods, corbelling continued as a practical technique for overhanging eaves, balconies, and decorative bands in brick and stonework. It is often superseded by true arches and vaults, but remains valued for its historical significance and visible craftsmanship. Relative weaknesses include limited span and potential for weathering under load if not properly supported.