Rib vault

A rib vault or ribbed vault is a special way builders make roofs for big spaces, like in churches. It uses a frame of crossed or diagonal arches called ribs to hold up the roof. Thin stone pieces fill in between the ribs. This makes the roof lighter and puts less pressure on the walls. The ribs carry the weight down to points like columns or walls. This lets architects build taller and thinner walls with bigger windows.

Rib vaults were first built by the ancient Romans in the 2nd century AD. They became very popular in Gothic architecture. This style helped create tall buildings filled with light. In Gothic churches, walls were often supported from outside by structures called flying buttresses. This allowed for huge windows made of colorful stained glass.

Cross vaults use narrow, arched ribs that cross each other to cover a space. The spaces between the ribs can be filled with small stone pieces. This makes the roof lighter than older styles. Thanks to the pointed arches in Gothic buildings, architects could change the height of the arches for different lengths. This made it easier to build two intersecting vaults of the same height but different widths.

Early history

The Romans used an early type of rib vault to make their groin vaults stronger. In these vaults, the brick ribs were hidden inside the concrete. This is different from later Gothic vaults, where the ribs stood apart from the stone panels, making them more flexible and strong. The Romans also used hidden ribs to support the concrete in domes, like in the Pantheon.

Rib vaults were not very common in Byzantine buildings, but a few were built at the Hosios Loukas monastery in Byzantine Greece. More rib vaults appeared in Greece after the Fourth Crusade, and they were also used in Lombard, Armenian, Persian, and Islamic architecture.

Cross vaults

Roman architecture

The first known example of ladder ribs used on cross vaults comes from the Villa of the Sette Bassi in Rome, dating from the mid-second century AD.

Islamic architecture

In Moorish architecture of Spain, Islamic architects used ribbed vaults more visibly. A notable example is found in the Great Mosque of Córdoba, begun in the 9th century and extended between 922 and 965. The Chapel of Villaviciosa, part of the mosque when it became a Roman Catholic church in the 13th century, has a dome resting on ribs and pendentives. At each vertex of the square, the dome intersects with another arch, creating junctions of three arches. Each corner has a small cross-vault dome. In other 10th-century domes of the Great Mosque, ribs intersect off-center, forming an eight-pointed star topped by a pendentive dome.

The crossed-arch vaults of the mosque-cathedral of Córdoba influenced later mosque buildings in Islamic regions, including al-Andalus and the Maghreb. Around 1000 AD, the Mezquita de Bab al Mardum (Mosque of Cristo de la Luz) in Toledo was built with a similar eight-ribbed vault. The dome is supported by ribs and pendentives that transfer its weight to the walls below. Similar vaults are seen in the mosque building of the Aljafería of Zaragoza. The architectural form of the ribbed vault was further developed in the Maghreb, with the central dome of the Great Mosque of Tlemcen, built in 1082, featuring twelve slender ribs.

Romanesque architecture

The rib vault was further developed in northern Europe during the 11th century as builders sought ways to construct larger stone vaults to replace wooden roofs, which often burned down. Romanesque cathedrals and churches usually used barrel vaults, with rounded arches, and groin vaults, where two vaults met at a right angle to cover the nave. The weight of these vaults pressed down on the walls, requiring thicker walls and smaller windows.

Saint-Philibert de Tournus has exceptional Romanesque vaults, built between 1008 and 1050. The nave and chapel have parallel tunnel vaults, while the aisles have groin vaults. Speyer Cathedral in Germany is the largest existing Romanesque church in Europe, featuring barrel vaults and groin vaults in the nave. The groin vaults were built in 1060 but reinforced in 1090–1103 with a traverse arch between each arch.

The Kingdom of England and the Duchy of Normandy became centers of architectural innovation in the late 11th century. Even before the Norman Conquest in 1066, King Edward the Confessor introduced Romanesque features to Westminster Abbey (1055–65). William the Conqueror constructed crossed rib vaults, called star vaults, in the domes of the Abbey of Saint-Étienne, Caen. The Abbaye-aux-Dames in Caen was roofed with stone groin vaults in the 1080s, one of the earliest uses in Europe of a groin vault to cover such a wide span.

Transition to Gothic architecture

Construction of the new church at Durham Cathedral began in 1093 under Norman bishop William de St-Calais. Originally intended to be built entirely with rounded-arch groin vaults, the builders experimented with pointed arches, which directed weight outward and downward. The space between the ribs was filled with thin stone panels. At the corners, the weight was supported by colonettes that transferred it to alternating columns and piers below rather than to the walls. These rib vaults were lighter than earlier barrel and groin vaults, allowing walls to be higher and have larger windows.

Work began at the east end of Durham Cathedral; the aisle vaults were complete in 1096, and the choir vaults by 1107. The nave vaults, with pointed arches, began around 1130. Thanks to the pointed arches, the upper level of the clerestory seemed to merge into the roof. However, the Durham experiment faced problems. The vault panels in the chancel were made of plastered rubble and were heavier than expected, leading to cracks. They were replaced in 1235. Meanwhile, experimentation in pointed rib vaults moved to France, where thinner panels were made of small cut pieces of stone.

The Romanesque Lessay Abbey in Normandy added early Gothic rib vaults in the choir around 1098, covering parts of the choir and nave. It was destroyed in World War II but rebuilt. The dome of the Romanesque Church of the Holy Sepulchre, Cambridge, begun in 1130, has ribs in the dome, though they were largely decorative. The Romanesque Cefalù Cathedral in Sicily, begun in 1131, features a Gothic rib vault.

The transition from Romanesque to Gothic can also be seen in the nave of Fontenay Abbey church (1147), where round arches of barrel vaults were replaced by vaults with slightly pointed arches.

Sexpartite vaulting

In sexpartite vaulting, each bay was divided by thin stone ribs into six compartments. The intermediate ribs diagonally crossed the vault, forming a pointed arch, with an additional intermediate pointed arch crossing from side to side. Since the ribs carried the weight, the vault panels were made of small stone pieces and were much lighter than traditional barrel vaults. The ribs transmitted the weight outward and downward through slender columns to piers below. The weight was not distributed equally; the diagonal traverse arches were supported by massive piers, while the intermediate crossing arch was supported by simple columns. With the weight carried by columns and piers instead of walls, the walls could be thinner and higher, allowing for larger stained glass windows.

The sexpartite vault appeared almost simultaneously in England and France. The first cathedral to use sexpartite vaults was Durham Cathedral, begun in 1093. Durham was originally planned with traditional groin vaults. The aisle vaults were completed in 1096, the choir vaults in 1107, and the north transept vaults in 1110. The nave traverse vaults, begun in 1130, were given pointed arches. Early examples of sexpartite rib vaults are found at Abbaye-aux-Hommes and Abbaye-aux-Dames at Caen. It also appeared in Noyon Cathedral (begun 1131), the square Gothic porch of Vézelay Abbey in France (1132), Sens Cathedral (begun 1135), the choir of the Abbey of Saint-Denis (begun 1140), Notre-Dame de Paris (begun 1163), Bourges Cathedral, and Laon Cathedral. Ribbed vaults were built by William the Englishman at Canterbury Cathedral and in St Faith's Chapel in Westminster Abbey (1180).

Quadripartite vaulting

A new variation of rib vault appeared during the High Gothic period: the four-part rib vault, used in Chartres Cathedral, Amiens Cathedral, and Reims Cathedral. The ribs of this vault distributed weight more evenly to four supporting piers below, creating a closer connection between the nave and the lower parts of the church walls, and between the arcades below and the windows above. This allowed for greater height and thinner walls, contributing to the strong vertical impression of newer cathedrals. The 11th-century Durham Cathedral (1093–1135), with earlier six-part rib vaults, is 73 feet high. The 12th-century nave of Notre-Dame de Paris, also with six-part rib vaults, is 115 feet high. The later Amiens Cathedral (built 1220–1266), with four-part rib vaults, has a nave that is 138.8 feet high. The tallest nave of all Gothic cathedrals is Beauvais Cathedral, though only a single bay was completed. It is 47.5 m (156 ft) high, slightly taller than the nave of St Peter's Basilica in Rome.

Complex rib vaults

Beginning in England with the Decorated Gothic style of the late 13th century, complex vaults emerged that included decorative ribs in addition to structural ones. Vaults continued to grow in complexity during the Perpendicular period, and similar extravagant rib vaulting appeared in late Gothic styles such as Flamboyant in France and Sondergotik in Central Europe.

Tierceron vaults use tertiary ribs (tiercerons) along with the main structural ribs of the regular quadripartite vault. This can be seen in the Decorated Gothic nave of Exeter Cathedral, begun in 1310, with a profusion of tierceron ribs. An octagonal tierceron vault completed in 1306 roofs the chapter house of Wells Cathedral, where 32 ribs spring from a single central pillar. At Ely Cathedral (1322–1342), tiercerons decorate the wooden vault of the octagonal lantern over the crossing.

Lierne vaults are also prominent in Decorated and Perpendicular Gothic architecture in England. Liernes are short decorative ribs that connect one rib to another. Most lierne vaults combine liernes and tiercerons, creating intricate star, web, or net-like patterns. The Perpendicular Gothic choir of Gloucester Cathedral features an extremely complex net-like vault covered in liernes, while the Lady Chapel of Ely Cathedral has a lierne vault concentrated around the centerline of the ceiling.

The Perpendicular Gothic fan vault is a unique type of rib vault found in England. The ribs are all of the same curve and spaced evenly, resembling a fan. Unlike Gothic vaults derived from pointed arches, the fan vault is made of semicircular conoids. The earliest example of fan vaulting is in the cloisters of Gloucester Cathedral. King's College Chapel, Cambridge, has the world's largest fan-vaulted ceiling.

Function

Rib vaults are a special way to build strong roofs over large spaces like church halls. They use thin stone ribs that cross each other to make a frame, with stone panels in between. These ribs spread the weight of the roof out and down, so the walls do not need to be very thick.

This lets churches have big windows and lots of light. The rib vault was created to let cathedrals grow taller and brighter. Early churches used thick walls to hold up their roofs, leaving little space for windows. With rib vaults, the weight is carried by the ribs to columns and outside supports called buttresses. This makes the walls lighter and allows for taller buildings and huge windows, like the famous rose windows.

Construction

To build a rib vault, workers first made a wooden scaffold that reached up to the top of the supporting columns. On top of this scaffold, they built a wooden frame shaped just like the ribs. Then, stone pieces for the ribs were placed into this frame and joined with mortar. After all the ribs were in place, the keystone was added at the top where they met. With the keystone in place, the ribs could stand on their own, held by the force pushing down and out. Workers then filled the spaces between the ribs with small pieces of brick or stone. Once filled, the inside surfaces were plastered and painted.

This process needed many skilled workers, including stone cutters, stone setters, and mortar layers, all working together with carpenters who built the needed scaffolds and models.