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Masterpieces of Medieval Open Timber Roofs
By Raphael Brandon, J. Arthur Brandon
Dover Publications, Inc.Copyright © 2005 Dover Publications, Inc.
All rights reserved.
FIRST DIVISION; OR, TIE-BEAM ROOFS,
IN treating of the roofs of the Middle Ages, it may be well to class them in four main divisions, namely,—Roofs with tie-beams; Trussed-rafter, or roofs; Roofs framed with hammer-beams and braces; and constructed with collars and braces, or with the latter only.
Of the first,—as we have before mentioned the earliest kind,—it may be observed that they were never entirely discarded by the Mediaeval Architects; they are to be met with in Norman, Early English, Decorated and Perpendicular buildings. In the first-named, they were probably the only description of roof in use; roofs belonging unquestionably to the Norman period are not often met with, nor did they, if we are to judge from the specimens that remain, exhibit much of beauty or science in their construction; and consequently we have not thought it necessary to give any drawings of them, as they offer nothing worthy of imitation, and can only be considered interesting in an antiquarian point of view.
The tie-beam was sometimes used in roofs of the Middle Ages quite independently of the other timbers, being simply laid across the walls, and in all likelihood pinned down to the wall-plates. Instances of this may be seen in Clymping Church, Sussex; the Church of St. Mary the Virgin, Wigenhall, Norfolk; and in the South Chapel of Bredon Church, Worcestershire; and many were the expedients to which the Builders subsequently had recourse, in order to retain and make it an ornamental feature in the design. At Southfleet Church, Kent, the tie-beams are beautifully moulded; cases occur, nevertheless, in which they are left quite plain, as in the Chancel of Northfleet Church, in the same county, where they are simple tie-beams in almost their natural roughness, while the roof itself, which is one of the trussed-rafter kind, is panelled and has moulded ribs with carved bosses at the intersections.
Various methods were resorted to, at different times, to endeavour to make this feature harmonize well with the rest of the Architecture; as the height or pitch of the roof varied, so naturally would the treatment of the other parts. In roofs of low pitch, which appear to have been in use at a very early period, the beam was made to bear the whole weight of the roof, as is the case in the one over the larger South Aisle of St. Martin's Church, Leicester,—hereafter illustrated and described. A somewhat similar roof, though rather steeper, occurs over the South Chapel of St. Nicholas' Church, Kiddington, Oxfordshire; in this instance a massive beam spans the Chapel, its underside being well moulded and connected with the wall-pieces by moulded curved braces forming a very obtusely pointed arch; the purlins rest directly on the beam, and the ridge is also supported on it by a strut or king-post, and further strengthened by short curved braces; the space between the top of the beam and the ridge is filled up, so as to give it the appearance of a solid triangular-shaped beam. A similarly constructed roof, but much later in style, covers the nave of Islip Church, Northamptonshire. The naves of Raunds Church, and Higham Ferrars Church, Northamptonshire, have good roofs of this description; the latter is clearly of Decorated date; the tie-beam is much cambered, and forms an arch with the curved braces, which are framed into it and spring from small shafts with caps and braces; the cornice and principal timbers are simply, but effectively moulded. An interesting roof of this date exists over the nave of Wimmington Church, Bedfordshire, where the tie-beam braces, besides being curved, are foliated.
In the Churches of the Middle Ages, a perfectly horizontal tie-beam is of extremely rare occurrence: where a tie-beam is used, we almost invariably find it cambered, as are also the collar-beams; even the hammer-beams will be generally found, on close inspection, to incline upwards from the walls. The disagreeable effect of a straight tie-beam was often further counteracted, by having curved braces framed from its underside connecting it with the wall-pieces, thus forming an arched support for it, as at Outwell Church, Norfolk.
In roofs of higher pitch the builders still endeavoured, with varied success as to effect, to retain the arched shape in conjunction with the tie-beams; a curious specimen exists at the Church of St. Mary the Virgin, Pulham,, Norfolk, where the beam literally divides the arch in two, and a similar instance is met with over the nave of Morton Church, Lincolnshire; the effect however is anything but agreeable or satisfactory. At Cransley Church, Northamptonshire, in the nave roof, the sweep of the curved braces, which is broken rather abruptly by the tie-beam, is continued by the rake of the rafter, thus forming a four-centered arch, intersected as in the two receding cases by the beam. None of these expedients, however, are at all to be compared with the effect of an unbroken arch, an excellent specimen of which is to be seen over the nave of Adderbury Church, Oxfordshire; where arched tie-beam braces span the nave, as do foliated ridge-braces each bay of the roof, springing from the tie-beams and framed into the ridge; the different timbers of this roof are nicely moulded and cusped.
In many tie-beam roofs the form of the arch was entirely omitted, as in the accompanying illustration from Swardestone Church, Norfolk. This variety of roof is by no means uncommon in the counties of Kent and Sussex, and it must be confessed that the effect produced by its small king-post with its cap and base and the curved braces springing therefrom to the principals and ridge, is certainly deserving of admiration. Mr. Bloxham, in his "Manual of Gothick Architecture," makes mention of an interesting variety of this description of roof, and his record is the more valuable as the Church in which it occurs is no longer used for the sacred purpose to which it was originally devoted: it now stands in the middle of a farm-yard, and is used as a barn! Mr. Bloxham describes the roof as follows:—"In the little desecrated Church at Horton near Canterbury, is an open wooden roof of a construction different to those which have been described. It is divided into bays by horizontal tie-beams, with the under parts moulded, resting on wall-plates, and on vertical wall-pieces supported by corbels, with a curved brace between each wall-piece and the tie-beam. From the centre of each tie-beam rises an octagonal-shaped king-post, up to about two-thirds in height of the valley of the roof, where it supports a longitudinal rib or beam; from the principals of the roof, at about two-fifths in height, spring plain braces, which cross diagonally, just above the longitudinal rib, and rest on the opposite principal; above these there is neither collar-beam nor apparent ridge-piece; from four sides of the king-post spring curved braces, both longitudinal and lateral, the former support the longitudinal rib, the latter the braces which cross above it. The roof is high pitched."
The roofs over North Walsham Church, Norfolk, are constructed in a very secure manner, the ties of the aisle roof pass through the walls, and form corbels for the wall-pieces of the nave roof, the entire workmanship is extremely rude, but the principle is good. A feature is here exhibited that became almost universal in roofs of late date; namely, the intermediate truss; its introduction must no doubt have originally been dictated by necessity, as in the present instance the bay or space between the main trusses (which are placed over the piers) would have had too great length and bearing for the purlins, and the crown of the arch prevented the use of an additional main truss; the builders were obliged in consequence to have recourse to some other plan, in order to give additional support to the purlins, and at the same time avoid interference with the arches. In the roof in question this has been very effectually accomplished by the adoption of double rafters on each side, strongly united and framed together; the common rafters are further strengthened by the introduction of a collar between each pair.
In hammer-beam roofs of a later period, as will be seen in the following plates, the difficulty of too great a space between the main trusses was sometimes overcome by introducing intermediate trusses without hammer-beams, as in the roof over the nave of Little Welnethom Church, Suffolk, (Plate 23,) and sometimes, as in the example from Trunch Church, Norfolk, (Plates 18, 19,) by retaining the hammer-beams in the intermediate trusses, but, diminishing the depth of the braces and wall-pieces beneath them. At times, as in Worstead Church, Norfolk, (where two clearstory windows occur over each arch of the nave, leaving a pier over the crown of the arch of equal size to those over the pillars,) the main trusses are placed over each pier of the clearstory. At other times, even on occasions where no necessity existed for them, the intermediate trusses without hammer-beams were introduced, as instanced in that splendid roof over the nave of St. Mary's Church, Bury St. Edmund's, Suffolk; this was probably done from a desire of producing a pleasing variety in the whole design, and avoiding the risk of a monotonous effect, which a long succession of hammer-beams might possibly create; but whatever the motive may have been which induced the Architect to introduce them in this roof, whether caprice or necessity, the effect is most satisfactory; and it may be safely affirmed that this magnificent specimen of Mediaeval Architecture is scarcely to be surpassed by any other in the land. The span of this roof is twenty-six feet, and the rise about twelve; the angels on the hammer-beams and in the cornice are exquisitely carved.
As the Perpendicular period drew towards a close, tie-beam roofs of very low pitch were of general occurrence; in fact, they were frequently almost flat, with no more rise to throw off the wet than could be obtained by the camber of the beams. These roofs were oftentimes profusely ornamented, as in that over the North Chapel of Wellingborough Church, Northamptonshire. In this instance the Eastern bay, as was very frequently the case, is panelled, while the others are left open to the rafters. The roof over the north aisle of Rushden Church, Northamptonshire, may be instanced as a particularly beautiful example of this periodCHAPTER 2
SECOND DIVISION; OR TRUSSED-RAFTER ROOFS.
THE next in succession, as we have classed them, to the tie-beam roof, that we discover amongst the roofs of the Middle Ages, is one with diagonal ties; of which there is an example in the porch of Stuston Church, Suffolk —a form of roof in all likelihood chosen for the purpose of gaining headway; and having once been had recourse to, its superiority, both as regards construction and general appearance, over the tie-beam, could not but lead to its being preferred and substituted for the latter.
In roofs of a wide span, each pair of rafters had a collar, and was also further stiffened by braces, crossing at times above the collar, and at others tenoned into its underside. The roof over the nave of Ely Cathedral furnishes a good example of this kind of covering; here, as we imagine to be the case in all other roofs of this description, each separate pair of rafters is trussed, so that, viewed from below, it presents somewhat the appearance of an arched ceiling; the soffit of the arch (if it may be so designated) of this roof is pentagonal—the two lower inclined sides being formed by the lower part of the rafters themselves; the two next, by braces passing obliquely from one rafter to its opposite neighbour; and the upper or horizontal side, by the collar, which intersects the braces: all these timbers are halved and pinned together with wooden pins.
In roofs of this character the rafters generally extended to the outside of the walls and formed the eaves and, consequently, the walls being of great thickness, and never carried up higher than the wall plates, a considerable space intervened on the inside of the Church, between the top of the wall and the underside of the rafter, which, if allowed to pitch upon a plate laying on or near the outer edge of the wall, would have but a very insecure hold: instead of this, the builders of old made use of the entire thickness of the wall, by filling up this space with upright pieces of timber lineable with the wall, (called struts,) which were framed and pinned into the underside of the rafters, and connecting these struts with the foot of each rafter by a horizontal piece of timber, into which each was framed, so as to assume the shape of a triangle whose base was equal to the thickness of the wall, and by thus forming a wide foot for the truss to rest upon they contrived to obtain an excellent hold, and so obviated in a great measure the danger of the roof spreading thus; and this in our opinion, as will be hereafter illustrated, gave the idea of the beautiful hammer-beam roofs that still adorn many of our sacred and other edifices. Several of these roofs are boarded underneath, and form a coved or polygonal ceiling, divided at the angles by mouldings and traversed by others, thus forming panels with carved bosses at the intersections. These roofs have frequently a single plate only, placed midway in the wall, the feet of the rafters being halved upon it, though sometimes they are found with both an internal and external' plate; or, as at Heckington Church, in the south porch, with a central plate and an internal one, the latter being moulded and forming a slightly projecting cornice.
In the early examples of this particular kind of roof the tie-beam was still retained, as may be seen in the specimen over the Chancel of Sandridge Church, near St. Albans, Herts, in which a moulded cornice projects from the wall, and is carried on notch heads, and into which the tie-beams ornamented with similar mouldings are framed. There are two tie-beams in the length of this Chancel, with about twelve rafters between each.
No great length of time however elapsed before we find the tie-beam altogether omitted, when the construction of simply-trussed rafters became and continued a very favourite style of roofing with the Early English and Decorated Architects; the trusses were then generally placed from about one foot two inches to one foot eight inches asunder.
More numerous examples of this kind of roof are extant than of any other; but they have, in too many instances, been concealed by lathed and plastered ceiling. There is every reason for believing that, even in their original state, they were occasionally boarded; though we may doubt if they gained much by the addition: certain it is that, for simple grandeur and picturesque effect, a plain trussed-rafter roof of good pitch cannot easily be surpassed.
Sometimes the form of the arch was perfected by the employment of curved braces affixed to the underside of the trusses, as in the annexed example, from Solihul Church, Warwickshire.
These arched ceilings are often met with in Somersetshire, where they are generally formed into panels, by ribs running horizontally with carved bosses at the intersections; between these ribs the panels are now mostly plastered, as at Crowcombe Church, Somersetshire.CHAPTER 3
THIRD DIVISION; OR HAMMER-BEAM ROOFS.
AFTER trussed-rafter roofs, the next kind of which we have to treat is that formed with hammer-beams, struts, collars, and braces; of which there are several varieties, all comprised under the general definition of Hammer-beam Roofs.
These roofs have hitherto been usually represented as lacking a portion of the tie-beam, as if in fact it had been partly cut away: an idea which we cannot but consider erroneous, and we shall endeavour to show that they owed their origin, as we have already stated, to the peculiar method in which the feet of the rafters were framed in trussed-rafter roofs, and were not in any way indebted for their formation to those roofs constructed with tie-beams.
There is no other resemblance between hammer-beam and tie-beam roofs than is to be derived from the circumstance of both of them being what are termed double-framed roofs; that is to say, that the common rafters are supported by an inner framework, composed of a pair of strong rafters called principals, into which the purlins are framed and further strengthened by means of braces, wall-pieces, collars, and either hammer or tie beams.
Beyond this, we imagine there to exist no more connexion between a hammer-beam and a tie-beam roof than there is between a tie-beam and a trussed-rafter roof: we may assert, indeed, that there is still less; for we find tie-beams used in conjunction with the earliest trussed-rafter roofs, as if in fact the builders had been afraid at first to dispense with so useful an ally. This is not the case in hammer-beam roofs, the earliest known specimen of which, the roof over Westminster Hall, is constructed without that member. This magnificent specimen, said to have been completed in the year 1399, which is characterised by such boldness, and what, when its span is considered, may be almost termed sublimity of design, is too familiar to the generality of readers to need illustration here; suffice it to say, that it differs in construction from most other roofs of the kind, in the introduction of a large main arch of timber springing from the bottom of the wall-pieces, and reaching to the underside of the collar-beams. The hammer-beams and struts run through this, and their braces complete the form of a trefoiled arch.
We cannot however bring ourselves to believe that so exquisite an example as the one in question could be the earliest roof of the kind executed, such perfection is not to be expected in a first attempt; it is however the earliest of which we possess any record, and though but a solitary instance, we may fairly adduce it as satisfactory evidence of the correctness of our supposition.
To illustrate further our hypothesis of the origin of hammer-beam roofs, we subjoin the accompanying illustration of the nave roof over St. Mary the Virgin's Church, Pulham, Norfolk.
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