Vault is an arched stone or brick ceiling structure that allowed pre-modern architects to span large spaces without timber roofs.
A vault is an arched ceiling structure of stone, brick, or concrete that uses the principles of the arch to span an interior space. The Romans were the first masters of large-scale vaulting, using their concrete to build the barrel vault (a continuous semi-cylindrical surface), the groin vault (formed by two intersecting barrel vaults at right angles), and the dome. The Baths of Caracalla (216 CE) and the Basilica of Maxentius (312 CE) demonstrate the spans Roman vaulting could achieve. Romanesque architects revived stone vaulting in the 11th and 12th centuries to replace the flammable wooden roofs of Carolingian churches. The Gothic ribbed vault — in which stone ribs concentrate the structural load along defined lines, with thinner panels filling the bays between — allowed the soaring heights of Chartres, Amiens, and Beauvais. English late Gothic developed the spectacular fan vault, in which ribs spread upward and outward like the bones of a fan, exemplified at King's College Chapel, Cambridge (completed 1515). The vault is the engineering achievement that made monumental interior space possible before steel and reinforced concrete.