What is a flying buttress?

The name “buttress” in architecture is given to a mass of masonry which stands out from the face of the wall, either to strengthen that wall or to resist the thrust from an arch or a roof/ The flying buttress was a Gothic innovation and is a kind of half-arch or half-bridge of masonry spanning the space from the buttress proper to the neighbouring wall.

Buttressing began in the great buildings of the later Roman Empire but it was not until the Romanesque period that really large outside buttresses began to appear. As the naves of the churches became roofed with ribbed vaults, a tremendous number of thrusts were concentrated into each bay and the flying buttress was evolved to counter them. Where the nave wall was of great height, as at Beauvais Cathedral, in France, two or even three half arches – one over the other – formed the flying buttress. 

By the 15^th Century, few large buildings were without flying buttress, which were often pierced and richly traceried. Many cathedrals in England, such as Exeter, Salisbury, Winchester and Sherborne Abbey in Dorset, show magnificent examples of flying buttresses as well as the richly decorated buttress pinnacles which often accompany them.