VÒLTA. – A masonry roofing structure, shaped in accordance with a curved surface and exerting a thrusting action on its supports (uprights); in it one distinguishes the lower surface, visible from inside the space, called the intrados, and the upper surface, generally concealed by the roof or by the floor of the space above, called the extrados.
On the basis of the form of the intrados, vaults are classified into various types, the principal ones being: barrel vaults, generally used in rectangular spaces, consisting of a cylindrical surface whose generating lines are normally parallel to the longer side, and whose directrix (that is, the normal section) may be semicircular, or a segmental arch, or a pointed arch, or polycentric; cross vaults, used instead for spaces approaching the square, formed by the intersection of two cylindrical barrel vaults, so that the walls are met along the directrices; groin vaults, formed by the intersection of two vaults as above, but with the walls meeting along the generating lines, thus constituting the complement of the preceding type; cloister vaults, that is, groin vaults truncated above by a horizontal plane; sail vaults; and basin vaults, consisting of a spherical calotte.
The vault originated from the need to cover large spaces by means of small elements that were easy to obtain or manufacture on site; this explains its emergence in the countries of the Middle East, which were poor in timber and cut stone. The Romans learned its construction from the Etruscans and subsequently made it the characteristic structure of their architecture, from which it was inherited by Christian religious buildings. The materials employed included brick, sometimes in special forms more suitable for construction; cut stone in suitably shaped voussoirs, so as to take account of the obliquity of the joints; and, finally, lightweight materials (for example, in Byzantine architecture [V. BIZANTINA, ARTE. ARTE], special vessels to reduce the weight; gypsum and similar materials in the eighteenth century, when the vault served a more decorative than structural function).
In religious architecture, the vault represented one of the determining elements of stylistic forms in every period, both because it influenced the iconography through the arrangement and spacing of the upright structures, and because it helped to give the interiors of churches a distinctive appearance, especially through their vertical development.
(courtesy of the Handmaids of the Sacred Heart)
(from F. Manardi, L'opera di A. V., Milan 1827) VOLTA, ALESSANDRO — Portrait, engraving by Giovita Garavaglia.
It is precisely these latter considerations that determined the invention of the groin vault, at first employed only in crypts (S. Eusebio di Pavia, S. Pietro di Tuscania, S. Vincenzo al Prato di Milano), then in the nave, but in association with other systems (with the dome in S. Babila di Milano, with the barrel vault in SS. Maria e Sigismondo di Rivolta d’Adda), and finally on its own (among the earliest examples, S. Ambrogio di Milano). This latter form became frequent as early as the second half of the 11th century. The main nave was then divided into regular intervals (bays) longitudinally, in order to obtain square or nearly square spaces; and, for the same purpose, the number of bays in the aisles was doubled, making two correspond to each bay of the main nave. The groin vault thus delineated the type of the Lombard church, which would also spread beyond the Alps.
A further improvement was introduced, always for the same purpose, in the final years of that century, with the introduction of ribs (v.); the need to connect them with the supporting structures led to the replacement of columns by the compound pier, consisting of a pier against which bundles of colonnettes are set; finally, the vault was raised, so that the diagonal arches, originally elliptical, became circular and in some cases even pointed. These arrangements, which appeared sporadically in Italy as early as the 12th century (cathedrals of Modena and Parma), subsequently spread fully in the following century, especially with Cistercian architecture (v.). During the Renaissance, the groin vault still found some limited applications (S. Maria del Popolo in Rome), though with the removal of the ribs, thereby also simplifying the form of the supporting piers; but the prevailing form—when a flat ceiling was not adopted—was the barrel vault, more consonant with the new classical sensibility (badia di Fiesole, S. Andrea di Mantova, S. Sisto di Piacenza). In the sixteenth century it became the usual form of roofing, transformed into the lunette barrel vault (through the intersection of cylindrical vaults of lesser rise), which made it possible to open windows above the side chapels in order to illuminate the nave, while at the same time accentuating the rhythm of the bays (S. Maria dei Monti and Gesù in Rome, Redentore in Venice, etc.).
In the seventeenth century, and even more so in the eighteenth, however, the Baroque conceptions, especially those of Borromini, which sought to replace the simple Latin cross with more complex forms, were also reflected in the configuration of the type of roofing, which no longer arose from the intersection of elementary geometrical forms but from the interpenetration of spheroidal and ellipsoidal solids, expressed in the complicated interweaving of ribs in different directions.
in the space surrounding the central part—generally covered by a dome—of baptisteries and other similar buildings (S. Costanza in Rome).
Later, around the 11th century, the use of the barrel vault began to be revived, generally limited to a chapel or two (that of S. Silvestro in SS. Quattro in Rome, that of the Assunta in S. Maria infra portas in Foligno), but sometimes adopted for covering the entire building, especially in Umbria (S. Pietro di Bovara, S.
These arrangements would be adopted especially in churches of Piedmont by Juvara, Guarini, and Vittone, subsequently spreading abroad and particularly in Germany and Austria, where in a certain sense they would reconnect with the tradition of the stellar vaults of the final Gothic period, which, however, found no applications in Italy at that time.
During the Neoclassical period, alongside the frequent use of the flat ceiling, the simple barrel vault would be revived and then continued throughout the nineteenth century.
Contemporary architecture, making use of the extensive possibilities offered by reinforced concrete, has produced new forms based on concepts different from the traditional ones, namely the so-called thin vaults of various types. Examples are found in the new churches of Pisa, Recoaro, Francavilla al Mare, and Milano, built following the competitions announced by the Pontifical Commission for Sacred Art, which promoted the study of new solutions of interest both from the constructive and from the aesthetic point of view.
The decoration of vaults follows the vicissitudes of taste and artistic conditions in the various periods. During the early Christian period it was entrusted predominantly to mosaic; in the Romanesque period, and especially in the Gothic, to fresco, particularly through great pictorial cycles. In the Renaissance it was generally decorated with coffers of classical inspiration (S. Andrea di Mantova), or with coffered designs following the same motifs as the flat ceiling (sacristy of S. Spirito in Firenze). In the second half of the sixteenth century, the use of fresco was revived, but in the form of large pictorial compositions—mostly glorifications of saints—for which the continuous surface of the barrel vault was well suited; fresco painting was later joined by stucco and gilding. The eighteenth century, however, preferred greater simplicity and reduced decorative richness, giving prominence to white stucco.