Vaulting (architecture)

“ Not more than three feet thick, they rise up to a height of nearly seventy feet to support a great stone vault. Four only of the six stand clear from floor to roof, for the two western are embedded at the bottom in the jambs of the gallery arches. From their capitals the vaulting ribs spread out in every direction, being constructively not unlike an English fan vault, and covering the whole roof with a network of lines. The piers are round, stand on round moulded pedestals, and are divided into narrow strips by eight small shafts. ”

“ The centering is then removed, and the vault, being in one piece, stands without abutment or thrust, apparently a better and more durable form of roof than our most scientific Gothic vaulting; certainly far cheaper and far more easily made, since it is literally cast on a mud form, which may be moulded into any shape the fancy of the architect may dictate. ”

“ Sometimes, however, in their barrel vaults (as in the piscina at Baiæ, mentioned by Professor Willis, and in the corridors of the Colosseum) , we find these strengthening strips appearing as ribs projecting downwards from the surface of the vaulting, and supported by projecting piers.
The application of this to groined vaulting is an obvious step, and adds vastly both to its strength and beauty. Let us suppose a length of vaulting so divided; we find at once that we are getting into a very sightly system, and one susceptible of excellent architectural treatment. ”

“ No better specimen of this form of vaulting can be referred to than that of the presbytery at Ely, built about 1240 to 1250, and the four bays immediately to the west of the crossing in Westminster Abbey, erected by Edward I. about 1280 to 1300 (Fig. 384) . The latter is the more perfect, as having level ridges;{210} the former, curiously enough, having ridges to the side cells which rise from the intersection towards the walls. I may mention that it is very common for vaulting with intermediate ribs to have ridges rising rapidly towards the central boss. ”

“ Such floors exposed the keep to be burned, and once well on fire it would certainly burn till it was gutted. The basement is now and then vaulted, but the vaulting is very rarely original, and when it is so the keep is late. The vaulting at the Tower and at Dover is modern brickwork; the Ludlow vault seems Early English; that at the lower part of Carlisle, that of Porchester, Brougham, Bowes, and Richmond, Decorated; the vaulting at Middleham, Newcastle, and Mitford may be original. ”

“ The ingenuity of the planning of the vaults is extreme, and though, at the same time, there is to our eyes an error in trying to do so much in so very small a space—nine vaulting compartments covered with varied vaults being contrived in a chamber only 21 feet square—it is to be observed that this is just one of the mistakes which arises from over-great education and skill, and is in marked contrast to the kind of design which we see in the simple, grave, but rude buildings which the less cultivated Christians were erecting at the same period. ”

“ In the Temple Church we have the curious circular aisle already described, being a specimen of the earliest era of true pointed-arched vaulting; while in the eastern portion, dating some forty or fifty years later, we have the most typical specimen conceivable of vaulting, all springing from a given level, and with level ridges. It is rendered the more marked in character by the division of the three ranges of vaulting by means of the pier-arches, which, coming close under the vaulting, assume the character of enlarged ribs. ”

“ Difficulties were met in forming intersecting vaults of unequal span, clumsy contrivances were resorted to, until, in the Transition period, 1145-1190, the introduction of the pointed arch solved the problem, and led the way to the development of Gothic vaulting. The Roman and Norman vaults were built upon temporary centering. A centre is a timber frame made like a roof-truss shaped{76} to the form of the arch ”

“ It is impossible for a dome of any kind to have the character of a Gothic vault. The difference between the two is fundamental. A Gothic vault is a vault of concentrated thrusts, and it requires effective concentrated abutments. A dome is a vault of continuous thrust, and for sound construction it requires continuous abutments, as in the Pantheon. Whatever use the ribs of Brunelleschi's vault may have, they do not, and cannot, perform the function of the ribs in Gothic vaulting. ”

“ Now, the vaulting of any space, if set out in square compartments, and having ribs of similar curvature and at equal distances, may be formed into a number of portions of this figure by merely drawing semicircles and quadrants, as the case may be, from apex to apex of the surrounding arches (Fig. 389) .
A remainder of the ordinary vaulting, with rising ridges, exists, however, above this extemporised fan, and the whole has to be dealt with artistically on a system suited to the new form. ”

“ The slight increase in mass quite suffices to account in the interior for the principal roof timber which rests upon it, and, with the vaulting-shaft, to continue upward the line of the nave-pier. But if the flying buttress, necessary to transfer the thrust of the vault, were built at this point, the arcade of the exterior would be effectually interrupted, and the space between the buttresses set off into a single bay, as in the wall of the aisle below, which does, in fact, represent a vault. ”

“ But in the nave, which was probably completed by 1196, [27] the vaulting system exhibits no such differences. Here the vaulting shafts (which are of unprecedented slenderness, and are not engaged with the pier, but are detached, as in the section, Fig. 23) are all of the same magnitude, notwithstanding the unequal weights which they have to carry.
FIG. 23. They are not, as in the choir, built up in courses of small stones, but are each composed of several, in most cases five, lengths of strong cliquart. Each group has all of its capitals (A, B, Fig. 24) at the springing of the great ribs. ”

“ There was still one difficulty, however, one slight failure both practical and theoretical in the vault architecture, which for a long time much exercised the minds of the builders. The ribs of the vaulting being all of unequal length, they had to assume different curves almost immediately on rising from the impost; and as the mouldings of the ribs have to be run into each other ("mitered" is the technical term) on the impost, there not being room to receive them all separately, it was almost impossible to get them to make their divergence from each other in a completely symmetrical manner ”

“ The original roofs of [96] most of our old churches, from their exposure to the weather, have long since fallen to decay, and been replaced by others of a more obtuse shape; but in general the height and angular form of the original roof may be ascertained by the weather moulding still remaining on the side of the tower or steeple. The interior vaulting of stone roofs was composed of fewer parts and ribs, which were often not more numerous than those of Norman vaulting, and does not present that complexity of arrangement which occurs in the vaulting-ribs of subsequent styles. ”

“ Within, there is no vaulting, and a mean wooden roof has been thrown across at about half the proper length. The nave, too, is covered with a wooden roof, a kind of coved roof with tie-beams. A real barrel-vault would be best of all; but a good flat ceiling, such as was common in Romanesque times, would do very well. It is one of the differences between French and English architecture that the French designers always meant or hoped to have a vault; the wooden roof in a French church is always a mere shift. ”

“ Noyon, Senlis, and Soissons, contemporary with these, are far less completely Gothic in style. At Le Mans the groined vaulting which in 1158 was substituted for the original barrel-vault of the cathedral is of very primitive design, singularly heavy and awkward, although nearly contemporary with that of Notre Dame (Fig. 118) .
FIG. 118.—LE MANS CATHEDRAL. NAVE.
DOMICAL GROINED VAULTING. The builders of the South and West, influenced by Aquitanian models, adhered to the square plan and domical form of vaulting-bay, even after they had begun to employ groin-ribs. ”

“ FAN-VAULTING. The next step in the process may be observed in the vaults of the choir of Oxford Cathedral (Christ Church) , of the retro-choir of Peterborough, of the cloisters of Gloucester, and many other examples. The diverging ribs being made of uniform curvature, the severeys (the inverted pyramidal vaulting-masses springing from each support) became a species of concave conoids, meeting at the 223 ridge in such a way as to leave a series of flat lozenge-shaped spaces at the summit of the vault (Fig. 136) . ”

“ The main transverse ribs of the aisle vaults are carried by responds consisting of five closely grouped monolithic shafts; and a cusped arcade lightens the wall space beneath the window string.
The buttress system is, like the internal vaulting system, largely wanting in structural completeness and functional efficiency. The clerestory wall is unbroken externally by pier buttresses. It has a continuous arcade of alternate groups of three wide arches, which open into the nave, and three narrow arches which are blind. ”

“ A groined vault does not of absolute necessity demand the use of ribs any more than the plain waggon-head vault. Even the latter was from an early period frequently divided into compartments or bays by transverse ribs, which were useful as a means of giving it rigidity; but in groined vaulting these were of nearly constant use, both for the same reason, and because the vault, being reduced at its springing to so narrow a footing, required this additional strength. The arrises, however, or diagonal lines of intersection, were always left without ribs. ”

“ In the construction of the vaulting of these later periods, we have a curious instance of the manner in which extremes meet. In the earliest specimens of vaulting, all the strength lies in the vaulting surface itself. As time went on, ribs were introduced, one after another, to strengthen and support it, till at length they amounted to a permanent framework of stone, centering on which the vaulting surface lay. ”

“ The ribbed vault was an imported idea, and was never systematically developed. Under the final dominance of French models in the second half of the thirteenth century, vaulting in oblong bays became more general, powerfully influenced by buildings like Freiburg, Cologne, Oppenheim, and Ratisbon cathedrals. In the fourteenth century the growing taste for elaboration and rich detail led to the introduction of multiplied decorative ribs. These, however, did not come into use, as in England, through a logical development of constructive methods, but purely as decorative features. ”

“ Q. Of what description was the Norman vaulting?
A. The bays of vaulting were generally either squares or parallelograms, though sometimes not rectangular in shape, and each was divided into four concave vaulting cells by diagonal and intersecting groins, thus forming what is called a quadripartite vault. Early in the style the diagonal [64] edges of the groins appear without ribs or mouldings; at an advanced stage they are supported by square-edged ribs of cut stone; and late in the style the ribs and groins are faced with roll or cylinder mouldings. ”

“ Higher up, in the thickness of the wall, about ten feet from the floor, and a little above the springing level of the vaulting in the parecclesion, is a long, narrow passage, lighted by a window at the east end, and covered by a small barrel vault, corbelled at the springing, on two courses of stone and three courses of brick laid horizontally, thus narrowing the space to a considerable degree. ”

“ As, however, this leaves the alternate piers unrepresented in the vaulting, it became frequent to carry across from this intermediate pier a single transverse rib crossing the diagonals at their point of intersection, and between it and those diagonals to introduce oblique vaulting cells, whose ridges strike from the centres of the half-bays to the point of intersection.
Dr. Whewell, followed by Professor Willis, has given this the name of “sexpartite” vaulting (Fig. 364) , ordinary vaulting being quadripartite, as having four cells. ”

“ Somewhat similar in idea is the vaulting of the crypt beneath the Sainte Chapelle at Paris, where, to avoid the segmental vaulting which would be the natural result of its limited height, the span is reduced by a range on either side of small pillars;—in this case so near the wall as to necessitate a great amount of stilting, and the introduction of a kind of tracery beneath the transverse ribs to give abutment to the central vault. ”

“ It is impossible to lay too much stress upon its importance, for it changed the entire geometrical system. Up to that time the construction of groining was wholly governed by the forms of the vaulting surfaces; the intersections being allowed to take their chance, and to present any irregularity of figure, while the wide surfaces of vaulting were apparently carried on mere pins’ points at the springing—correct enough as a mathematical figure, but ill calculated for strength. ”

“ In the vaulting of a Gothic roof it is no deceit to throw the strength into the ribs of it, and make the intermediate vault a mere shell. Such a structure would be presumed by an intelligent observer, the first time he saw such a roof ”