The Probert Encyclopaedia of Architecture

VAULT

In architecture, a vault is literally an arched roof. The term is also used for a chamber with such a roof and, as these are often underground, it has come to be used for cellars where wine is stored.

The simplest and most ancient kind of vault used over a rectangular area is the cylindrical, called also a barrel, and sometimes wagon vault. This springs from the two opposite walls, and presents a uniform concave surface throughout the whole length, Vaults of this description were used by the Romans, the earliest people by whom vaulting, properly so called, was employed. The Romans also first introduced groining, formed by the intersection of vaults crossing each other at right angles, and some of their constructions of this kind were of very large size. Arches which cross each other do not always correspond in width. In such cases they sometimes spring from the same level, and consequently are of unequal heights and sometimes the springing of the narrower vault is raised so that the tops are on the same level. Domical, or hemispherical, vaulting over a circular area was likewise practised by the Romans, of which the Pantheon at Rome exhibits a magnificent example 142 feet in diameter. The decorations employed on Roman vaulting consist chiefly of panels, and flat bands of ornament following the curve of the arch. The application of ribs at that period was unknown.

Domical vaulting is often used over polygonal and sometimes over square areas, the plan of the dome consisting of a number of flat sides conformable with the sides of the building on which it is placed. Hemispherical domes are also used over polygonal buildings, and even over square ones, their diameter being made equal to the diagonal of the square on which they are placed. This last-mentioned kind of vaulting is considered to be characteristic of the Byzantine school of architecture.

In the Norman style cylindrical or barrel vaulting, as well as groined vaulting, is used. The former of these is either perfectly devoid of ornament as in the chapel in the White Tower of London, or has plain and massive ribs at intervals, following the direction of the curve of the arch. In groined vaulting the cross-vaults are not infrequently surmounted, or stilted, when they are of narrower span than the main vault, though sometimes, in such cases, they are both made to spring from the same level. But in general the parts of the building are so arranged that both vaults are of nearly or quite the same breadth. In the early examples there are usually no ribs except the cross-springers, which are often perfectly plain and very massive, and even these are not always found, but the later specimens commonly have ribs on the groins, and both these and the cross-springers are often enriched with mouldings, zigzags, and other ornaments.

In the Early English style, when the use of the pointed arch was permanently established, the same form was also given to the vaulting and groined vaults at this period were universally adopted. In buildings of this date ribs are invariably employed, especially on the groins. The simplest arrangement of them consists of the diagonal or groin ribs, cross-springers, and the longitudinal and transverse ribs at the apex of the main and cross vaults. But these two last, in some examples, are omitted. Additional ribs are sometimes introduced between the diagonals and cross-springers. In some buildings in Britain, and in many on the continent, the vaulting is constructed with the main vault double the width of the cross-vaults, with the diagonal ribs embracing two bays or compartments of the cross-vaults, as in the choir of Canterbury cathedral. Surmounting, or stilting, in the manner before alluded to, is common in this style and several different varieties of construction are found, but they do not in general very materially affect the appearance of the vaulting.

Decorated style vaults for the most part differ little from those of the preceding style. The longitudinal and transverse ribs are occasionally, but not often, omitted, and the number of those on the surface of the vaulting is sometimes increased and in some examples ribs are introduced crossing the vaults in directions opposite to their curves, so as to form in some degree an appearance of net-work upon them.

In the Perpendicular style the general construction is much the same as in the Decorated style, but the ribs are often more numerous, and pendants are not uncommon. Towards the latter part of this style fan-tracery vaulting was introduced. This has no groins, but the pendentives are circular on the plan, and have the same curve in every direction, resembling inverted curvilinear conoids, and are generally covered with ribs and tracery branching out equally all round them. The middle of the upper part of the vault, between the pendentives, is usually domical in construction, and frequently has a pendant in the centre of each compartment.
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