Rib (architecture)

“ Its vaults exhibit the peculiarity of having no transverse ribs; but they have tiercerons, longitudinal and cross liernes, and a surface rib in each lateral cell. The springing of the longitudinal arch and of the great ribs is at the same level—which is that of the clerestory string, and there is, therefore, no narrowing of the lower part of the vaulting conoid upon the line of the clerestory buttress, such as is found in true Gothic. ”

“ The first remarkable point of the building is the roof. It generally consists of tiles of very deep curvature, which rib it into distinct vertical lines, giving it a far more agreeable surface than that of our flatter tiling. The form of the roof, however, is always excessively flat, so as never to let it intrude upon the eye; and the consequence is, that, while an English village, seen at a distance, appears all red roof, the Italian is all white wall ”

“ It will be better understood by means of Fig. 358, in which a transverse rib, two diagonal ribs, and two wall ribs meet at their common springing line, and so intersect and unite one with another as to produce a section at the base composed of portions of them all. Now, a drawing of this group of ribs will at once show that their combined and united form must extend to some considerable height above the springing; and so far as it reaches, which is often some 8 feet or 10 feet in height, they cannot possess an individual existence (Fig. 359) . ”

“ Vaulting, which had already been enriched by the multiplication of ribs, was further complicated by cross-ribs (liernes) , subdividing the simple spaces naturally produced by the intersection of necessary ribs into panels; these, again, were filled with tracery. The fan-vault was developed by giving to all the ribs the same curvature; the outline of the fan is bounded by a horizontal circular rib, and its effect is that of a solid of revolution upon whose surface panels are sunk. The cloister of Gloucester presents the earliest and perhaps the most beautiful example. ”

“ In the west wall, where is the entrance from the mural gallery, is a recess, 12 feet broad and 2 feet deep, above the grand entrance of the keep. Its angle is replaced by a nook-shaft, the particulars of which show that though the walls and the position of the windows are original, the floor-level has been raised, and a fireplace inserted in the south wall. Like the vestibule, this room has had its flat timber roof replaced by a high-pitched vault in two bays, groined and ribbed, and with a dividing rib. All the ribs spring from semi-octagonal piers inserted into the old walls. ”

“ This is easily adjusted by drawing the curve of the back of the rib, whose position is first determined, drawing against it the vertical line of its intersection with the next rib, and then, from the apex point of the adjoining rib, to draw its curve through the point of intersection, which will give on the springing line the distance backward or forward at which the{194} springing section of that rib should be placed (Fig. 361) .
The ribs of all vaulting of early date are square and flat at the back; the vaulting, which is often very thick, passing over and resting upon their backs. ”

“ 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. ”

“ The stone ribs which spring directly from the uprights with but the slightest pretense at vaulting shafts in little{122} round mouldings with slightly marked capitals, are really the arches which carry the whole stone structure of the roof. The great pendants into which these ribs disappear, and which themselves form the basis of the fan-vaulting system, are of course without constructional value. The roof is to be taken as an elaborate piece of geometrical carving, ingeniously arranged in the semblance of a constructional work ”

“ Wonderful skill is often evinced in the arrangement of these patterns, which, traversing the changing planes or surfaces of the vaulting, produce in the perspective an extraordinary diversity of effect. These ribs have received from Professor Willis the name of “Liernes,” a term given by Philibert de l’Orme to the ridge-ribs (perhaps in common with these) , but, as we are short of an English name for these cross-ribs, it comes in conveniently to our aid. ”

“ The huge east window, which is not splayed, has a deep rear-vault bounded by a massive rib, whose outer edge rests on slender engaged shafts with foliage on their capitals, while the inner edge ends in bunches of foliage. Between this rib and the tracery is another rib springing on the north side from a bunch of foliage and on the south from a grotesque corbel. ”

“ When in weaving silk or linen there may be two hundred threads to the running inch instead of ten, the designer can introduce curves almost as flowing as if he were a painter. So too in architecture: the log hut was perforce straight in its every line; stone and brick made possible the arch; iron and steel are bringing in a free choice of the best lines, whether straight or curved, all with a new sprightliness, as witness the best of our office-buildings in New York, such as the Whitehall, Trinity, and Empire Buildings. ”

“ The groin-ribs, intersecting at the centre of the vault, divided each bay into four triangular portions, or compartments, each of which was really an independent vault which could be separately constructed upon light centrings supported by the groin-ribs themselves. This principle, though identical in essence with the Roman system of brick skeleton-ribs for concrete vaults, was, in application and detail, superior to it, both from the scientific and artistic point of view. The ribs, richly moulded, became, in the hands of the Gothic architects, important decorative features. ”

“ Ridge ribs and surface ribs, which sometimes appear later, do not occur at this epoch. Of the constructive ribs none are ever wanting, nor are independent supports for them ever wanting in the piers. Throughout the building there is a structural reason for every member that meets the eye, though the degree of perfection with which minor structural exigencies are met continues to vary.
In the nave of St. Leu d'Esserent, whose vaults we have just considered, the lower piers and the vaulting shafts are wrought substantially on the model of those of the westernmost pier of Paris ”

“ Some buildings were vaulted in every storey, giving good examples of really fireproof construction; others were fireproof through one or two storeys, and timbered above; and others, again, had timber floors throughout. In secular structures we find trabeated architecture in its truest form—not stone beams, which, when extended beyond very narrow limits, go against the nature of the material, but real beams of wood, used in a thoroughly sensible and constructive manner. ”

“ Ribbed vaulting made possible higher ceilings, spanning wider areas, than in Romanesque churches. [13] In the second place, the pillars supporting the ribs were themselves connected by means of flying buttresses with stout piers of masonry outside the walls of the church. [14] These walls, relieved from the pressure of the ceiling, now became a mere screen to keep out the weather. They could be built of light materials and opened up with high, wide windows.
THE POINTED ARCH Ribbed vaulting and the flying buttress are the distinctive features of Gothic architecture. ”

“ They are entirely executed in red and black brick, the cusping being all done in moulded brick. As a rich piece of colour this work is very valuable, but architecturally its sole merit is a kind of picturesqueness, which it certainly has in great force.
The fact is that in northern Germany all the domestic architecture was very full of faults; the fronts of the buildings were very seldom at all ruled by the roof line, and their stepped gables, traceried, mullioned, and pinnacled, had no reference to anything save a desire to look well ”

“ From the first sun-dried bricks, sometimes combined with stone, were the chief materials used, even the grander structures of the best period such as the huge palaces and halls were of plastered brickwork, stone having been as a general rule reserved for such works as temples, theatres, and triumphal arches. Concrete was also largely employed, and timber in many cases was turned to account for roofing. The most distinctive peculiarity of the architecture of the Romans is the vaulted roof, which they employed in an infinite variety of ways, introducing it at every possible opportunity. ”

“ The external and the internal covering of a building are very often not the same; the outer covering is then usually called a roof—the other, a vault or ceiling. In not a few Gothic buildings, however, they were the same; such buildings had what are known as open roofs—i.e. roofs in which the whole of the timber framing of which they are constructed is open to view from the interior right up to the tiles or lead. Very few open roofs of E. E. character are now remaining, but a good many parish churches retain roofs of the Dec., and more of the Perp. ”

“ In southern architecture the roof is of far less importance; but here the soul of domestic building is in the largeness and conspicuousness of the protection against the ponderous snow and driving sleet. You may make the façade of the square pile, if the roof be not seen, as handsome as you please,—you may cover it with decoration,—but there will always be a heartlessness about it, which you will not know how to conquer ”

“ The claim of Italy to be the first to use the diagonal ribs is denied by most French archæologists, but is put forward by the Italian scholar Rivoira and by Mr. Arthur Kingsley Porter. [12] The latter cites the church of Sannazzaro Sesia as showing proofs that its high nave was Gothic vaulted by 1040. For a century, he says, the Lombard churches used diagonals, especially in Milan, where wood was scarce and it was easier to build permanent brick ribs under the groin vault than to mold the groin on a temporary substructure. Diagonal ribs were invented, he thinks, as a device to economize wood. ”

“ The roof and chimneys should be kept out of sight as much as possible; and therefore the one very flat, and the other very plain. We ought to revive the Greek custom of roofing with thin slabs of coarse marble, cut into the form of tiles. However, where the architect finds he has a very cool distance, and few trees about the building, and where it stands so high as to preclude the possibility of its being looked down upon, he will, if he be courageous, use a very flat roof of the dark Italian tile. The eaves, which are all that should be seen, will be peculiarly graceful ”

“ The roof of the transept, which we have described as crossing the building about the centre of its length, differs from that of the other parts, its general form being semicircular instead of flat, and rising above the rest of the building so as to show the whole of the semicircle externally. This roof is supported by arched timber ribs placed twenty-four feet apart, or one over every column, which forms a socket, into which the foot of the rib is fitted and secured by iron straps. ”

“ Turrets with many airy finials, springing from flying buttresses that were adorned with figures of lions, dragons, and other symbolic creatures, rise above equally ornate parapets, the dignified single-centred arch was replaced by a four-centred form, and rectilinear lines superseded the beautifully flowing tracery of earlier windows. It was, however, the complex and exquisitely delicate groined roofing that chiefly characterised the Perpendicular style, lending to the interior of the buildings in which it was employed an ethereal charm that has never been surpassed. ”

“ The blocks of stone are in many cases much larger than they appear, channels being cut upon them to simulate joints. The arch of one window, for instance, which by the rustication would appear to be made up of fourteen voussoirs, has in reality only three. The same lack of conformity of the simulated jointing with the true masonry joints is noticeable also in many parts of the façade of the Riccardi, and I know not how general this treatment may be in the architecture of the Renaissance. ”

“ Were our brickwork like that employed in the buildings of Nero's time, almost close-fitting as carved stone, without visible cement, uniform in shape and tender in colour, sharply moulded into every architectural member and ornament, and put into every comely disposition that can copy, without simulating, stone, one would be glad to see such an adaptation of a material, cheap, manageable, and everywhere at hand. ”

“ In the north curtain is a half-round mural tower with four loops, and of one story, open at the gorge. The water-table of a double-gable roof is seen within, and the central gutter projects as a spout outside. Further on is a blocked-up arch, probably an early postern, and, still further, the seat and drain of a large garderobe, beneath an arch in the wall, 8 feet broad. Above is a plain corbel, hollowed to receive the wall-plate of a roof, and no doubt one of a series. The country people call it the gallows. ”