Rib Vault

A rib vault is a groin vault reinforced with a framework of projecting stone arches, called ribs, built along the diagonal and transverse lines where the vault's curved surfaces meet. The ribs were typically raised first to form a stone skeleton, which was then filled in with lighter, thinner masonry panels called webs, so that the ribs carry much of the vault's structural load while the webs between them can be built thinner than a plain groin vault requires. First developed within Romanesque architecture and elaborated through the Gothic period, rib vaulting let builders cover wider spans, raise vaults higher and open larger windows in the walls below, and it became one of the defining structural techniques of Gothic cathedral construction.