Navel (architecture)

“ Every child who has ever built with bricks feels the reckless wastefulness of using for steps the bricks so much needed for walls and towers. And who has not experienced the aggravation of finding when his tower is built that he has used up all the long bricks near its foundation and has now none left which are long enough to lay across its summit and form its roof? The slabs of board should be, like the bricks, of seasoned oak, and should be an inch thick. There should be plenty of arches—so as to render possible some sort of resemblance to Norman and classical architecture. ”

“ A noble arch spans the intersection of the transepts, and lofty columns with richly carved capitals divide the nave from the aisles and the latter, of which there are five, from each other, but the roof is only a flat wooden one, the external walls are wanting in dignity and solidity, whilst the height, 100 feet only, is quite out of proportion with the otherwise noble dimensions. ”

“ The proportions of the internal elevation are such that, if the entire height of the wall be divided into nine parts, four go to the main arcade, two to the triforium or gallery, and three to the clerestory (Fig. 253) .
Fig. 253.—Sectional view of Nave, St. Alban’s.
The arches of each are of three orders, and are, for the most part, without shafts; the section of the jamb and arch being the same, severed only by a simple{102} impost. A broad pilaster buttress runs up the face of each pier from floor to ceiling. ”

“ The noble western façade, with its profuse and ornate ornamentation, and the fine square towers flanking it, each pierced with effective openings and adorned with grotesque gargoyles, contrast with the slender central spire—which, by the way, is modern—tiers of graceful flying buttresses, and the numerous groups of pinnacles, whilst the long line of the great roof ridge brings into relief the comparative intricacy of the design of the rest of the building, especially of the extremities of the transepts with their fairy-like arcading, beautiful sculptures, and grand rose windows. ”

“ In this respect the structure of stone is mainly predominant with the self-substantive type of building, although even among the Egyptians, in their colonnades bordered with plinths, other considerations supervene, which the structure of wood is able more readily and in the first instance to satisfy. Conversely we do not find that classical architecture restricts itself entirely to buildings of wood, but, on the contrary, where it is elaborated in conformity with beauty, executes its buildings in stone ”

“ 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. ”

“ 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. ”

“ It is not so much that the walls are thin, as that they have disappeared: there are no walls—only a series of piers dividing windows, the opening filled with glass being much greater, if measured along a horizontal line running through the windows, than is the extent of the solid masonry. You see at once wherein there is an excuse for the saying “a wall of glass with a roof of stone.” But there is more than this: the primary object of the designer has been to treat his construction as the main inspiration of his design. ”

“ 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. ”

“ The stone roof-plate, enriched with mouldings and foliage, and, perhaps, supported on sculptured corbels, becomes the crowning horizontal feature; and the parapet—the defence of the workmen engaged on the roofs—is pierced into tracery, or forms a miniature arcade, giving delicacy and lightness of effect to the generally massive structure; while the bell-tower, raised high to make its voice heard from afar, becomes the culminating ornament of the whole exterior. ”

“ 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. ”

“ The Pier-arches, in early examples, are perfectly plain, and square edged, without mouldings or ornament; but more frequently they carry one or more heavy rolls on the angle of each order of the arch; and are often ornamented richly with concentric rows of chevron, billet, and other Norman ornaments.
The Vaulting or Roof-shaft is usually a semicircular shaft rising from the floor—on the face of every alternate Pier—to the springing of the vault or roof. ”

“ 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 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 ”

“ The windows were generally spaced carefully and were in harmony with the front door, making an attractive exterior. The walls were of wood, often with a layer of brick to keep out the cold and also to form a better protection. The roofs, more especially in the early houses, were very [Pg 149] steep, since they were planned for thatching; later on, when shingles came into use, they grew lower and wider. It was not until 1700 that the gambrel roof came into style. In considering the evolution of the house we must look backward, and thus we come to realize the progression of architecture. ”

“ The Romanesque architecture of Lombardy, Germany, and Burgundy had wrought out the arrangement of the groined vaulting and the distribution of the forces arising therefrom, and the designing and construction of the necessary buttresses. The subordination of the various members, the division of the piers and arches into orders, each performing a distinct function, the erection of a vaulting shaft at each pier to receive the ribs of the vaults, the construction of ribs to form the groins and carry the panels of the vaults, had all been fully accomplished. ”

“ A comparison, for example, of the plans of the Hypostyle Hall at Karnak (Fig. 11, h) and of the Basilica of Constantine (Fig. 58) shows at once a radical difference in constructive principle between the two edifices, and hence a difference of style.
STRUCTURAL PRINCIPLES. All architecture is based on one or more of three fundamental structural principles; that of the lintel, of the arch or vault, and of the truss. The principle of the lintel is that of resistance to transverse strains, and appears in all construction in which a cross-piece or beam rests on two or more vertical supports. ”

“ The groining requires that the aisle wall shall be fully as high as the crown of the arches between the aisles and the nave; and, as the aisle roof demands some reasonable height, it follows that there must be a considerable space of wall above the arches. This may be dealt with in several ways. If the nave be unvaulted, it is a blank space, or may be pierced by an arcade or other openings. If the nave is groined without a clerestory, the space is partly occupied by the springers of the vaulting, and the intervals may be pierced. ”

“ Dignified simplicity and sense of space are the chief characteristics of all three buildings, massive columns upholding the arcading flanking the naves, whilst the walls of the aisles are unbroken by triforia, the piers at Speier and Worms being carried right up to the clerestory windows, whilst at Mainz two arches are placed one above the other, the vaulting of the nave springing from the upper tier. ”

“ The arcades between the streets are imposing by number and repetition as well as by massiveness, and by the Roman durability which marks all the work. They suffer, however, from two causes. The coping, the arches, and the piers, which are the emphatic parts of structure, are lighter in color than the unemphasized and rock-faced fields of the wall, and this is always a misfortune when it is not an error. ”

“ That the plan of three naves is good, congruous, and deserves to be carried out, provided that the vault of the second arch of the middle nave is taken down to the springers, and that they also are taken down, so that the work may be raised by its dimensions ”

“ There being no aisles, there are, of course, no piers; but the vaults are supported by shafts, five in a group, which rise against the walls, unbroken from the pavement to the springing of the arches. Narrow pointed windows, one in each bay, and each divided by a mullion, are the only openings. The apse has a Gothic vault and traceried openings; but the general character and aspect of the building, especially of the exterior, is little removed from that of a Romanesque structure. ”

“ The vividness of the expression of mechanical forces in architecture depends, moreover, upon the kind of materials employed; it is greater in marble than in wood, and less in our modern constructions of steel and glass, where the piers move in single vertical lines from the bottom to the top of the building, than in the old forms, where the upper part of the building is frankly carried by the lower. ”

“ The inner thickness consists of the framework of the coffers, which is of brick, and the filling-in of the coffers, which is of rubble or concrete. This would form the centering on which the outer shell was built, which is a curious tissue of arches, each rising from the crowns of those below it, and so disposed as to concentrate the pressure upon points in the wall which intervene between the cells. ”

“ In the interiors the simple Early English vaulting is superseded by roofs divided into a great number of different compartments, the points of intersection being marked by stone bosses or masses of carving, whilst increased lavishness of decoration characterises every portion of the building, mouldings of a great variety, amongst which the ballflower is of frequent occurrence, being introduced wherever possible. ”

“ The vault ribs and the vaults themselves were now also made lighter. And finally the ribs were more closely grouped at their springing—being made to interpenetrate, more or less, by which means the pressures were concentrated to the utmost, while the sustaining shafts and piers, for which the best materials were selected, were reduced to a minimum of thickness. As this development of an independent framework progressed, the intervening walls, now no longer needed for the stability of the fabric, were also reduced in thickness ”

“ The Roman builders usually strengthened their vaulting by narrow strips of brickwork or cut stonework from pier to pier, constructing the rest of inferior materials. Their groined vaults were similarly fortified at the lines of intersection ”

“ On either side of the west front of many Romanesque buildings, more rarely also from the point of junction of the transepts and nave, rise lofty square or octagonal towers, the earlier with flat, the later with more or less steeply pitched roofs, that gradually developed into the tapering spires so characteristic of the Gothic style. ”