The Hall Of The Mddle Temple

Its stability depends solely on the permanence of its joints, and the safeguarding against decay, especially in the hammer-beams and the wall-posts. The huge cornice and the hammer-beams are, in reality, the only tcnsional members; the others are in compression. As an example of clever construction on the part of the fifteenth-century carpenters this roof of Xecdham Market Church is a truly astonishing achievement.

The great curved rib, as in Fig. 44, No. 24, when used in conjunction with the hammer-beam, marks the zenith of timber-roof construction in England. The view of Gainsburgh Great Hall, illustrated in Chapter VII of this volume, shows the rib as a great moulded arch-brace, springing from the wall-corbels to the collar. This Hall is in a timber building, and the stress of the entire roof is carried on great posts from the ground, tenoned into the ends of the principal rafters. These posts appear, 011 the outside of the Hall, as great timber buttresses on their inside faces is a solid abutment, probably a branch growth on the original tree itself, which was especially selected for the purpose, on which the continuation of the arch-rib to the corbel is moulded. Above this springing, the arch-rib rises, in two sections, to its apex, where it is tenoned

Suffolk Roof Church

NEEDHAM MARKET, SUFFOLK, ROOF OF NAVE.

NEEDHAM MARKET, SUFFOLK, ROOF OF NAVE.

Double-aislerl hammer-beam tvpe, with clerestory. 2ij It. 0 ins. span. I, ft. between hammer-posts. ^o ft. long over all. Built about 1460.

yo into the collar. At the point of junction of the two sections of the rib with the principal rafter, they are housed into it with long slotted tenons, secured by wooden pegs. With the solid abutments to this arch-rib, it will be len that the corbels have no function other than an ornamental one, and even this latter is questionable when it is remembered that the original carved corbels have disappeared and have been replaced by others of cast iron in the ornamental style of a modern girder railway bridge. Surely even cast iron was never put to more ignoble use.

It has been pointed out, at the outset of this chapter, that the chronological arrangement of timber roofs does not show their progressive development. Of the three remaining examples of the English timber roof still to be considered, Westminster Hall (i395) is the earliest. The roof of the Exeter Law Library (the date of which is obscure, but which is certainly later) and Gainsburgh Hall, completed in 1484, would follow in order, but to adopt this method would involve taking the most complicated and the largest timber roof in existence and to descend from this to the comparatively simple type of Gainsburgh Hall. The latter, also, is a timber-framed building, and problems of roof construction can be solved by means not possible in the case of walls of stone or brick.

The roof of the Exeter Law Library, Figs. 87, 88 and 89, has every appearance of being copied from Hugh Herland's great roof in \\ estminster Hall. Similar winged

1
  • 25?'9'-
  • 25?'9'-

angels are carved on the ends of the hammer-beams, the same form of great arch-rib commences from the collar, intersects with the hammer-post and continues to the wall corbel, where it joins with the arch-brace from the hammer-post. In Westminster Hall, however, the arch-rib intersects with the hammer-post at about half its height and with the hammer-beam well away from its wall-end, thus bracing the upper and lower portions of the compound roof together. In the Exeter roof the rib is kept further back, and instead of intersecting with the hammer-beam, the latter is actually tenoned into the rib itself, in the same manner as one of an upper tier in a double hammer-beam roof is tenoned into the principal. It is here where the first important difference between the Exeter and the Westminster Hall examples occurs. There is no large raking traceried spandrel behind the rib above the hammer-beam as in Westminster Hall. In the Exeter Roof this is quite small, with a simple pierced panel, and below the hammer-beam it is solid.

Above the cambered collar is a waggon ceiling, formed under the collar-purlin, which is arch-braced to the great purlin, thereby forming the ribs to this barrel ceiling. In Westminster Hall, with its enormous height and pitch of roof, there is an upper and a lower collar, braced together with collar-posts and completely traceried up to the ridge.

Between each of the four main trusses of the Exeter roof is a subprincipal which finishes with a forked brace, cut from the solid, on a small carved hammer-beam, projecting at an «ward angle from the wall-plate, this tilt dispensing with any braces below. Across this sub-principal, at its centre, is a small moulded purlin, and from the intersection two raking struts are taken to the junction of the arch-ribs with the wall-plate. The central meetingpoint of the principal purlin and raking

Fig. 85. needham market.

View showing windows of clerestor\ ,

Fig. 85. needham market.

View showing windows of clerestor\ ,

Hammer Beam Construction

NEEDHAM MARKET, SUFFOLK.

NEEDHAM MARKET, SUFFOLK.

\ iew showing details of hammer-beams, hammer-posts, tie-beams and ashlanng, and carved cornice

struts is covered by a boss carved with the representation of a human head. From behind this sub-principal, which is in the form of a large flattened arch-brace (see Fig. Sq), two other braces, with traceried spandrels, carry down from the great purlin to the hammer-posts, at some distance from the hammer-beam, joining others which rise to the apex of the great arch-rib (see Fig. 87).

Although obviously designed in imitation of Westminster Hall, this Exeter roof differs largely in its construction from its model. It is framed in a very solid and rather clumsy manner, with heavy baulks of timber, and lacks the grace and scientific devising of the Westminster original.

The roof is carried, mainly, 011 the huge piece of timber, which contains, in the one piece, the wall-post and the lower section of the inner or large arch-rib. This is tenoned into the principal, and has a solid abutment from which the upper sections of the rib continue. The principal rafter is tenoned into the hammer-post at its upper extremity' and at the other end into an extension of the hammer-beam on the wall side of the arch-rib. The hammer-beam proper, being tenoned into the arch-rib on its inner face, has 110 definite connection w ith this extension piece, which is fixed by being mortised on to the upper end of the wall-post, held firmly to its tenon by pegs. This false hammer-beam extension piece takes the thrust from the principal rafter. The real hammer-beam is tenoned into the lower section of the arch-rib or the wall-post,- -which are here the same, as both are contained in the one solid timber, and is supported by the lower internal rib-brace, which is tenoned into the hammer-beam at its one end, and into the wall-post at the other.

The main collar-beam- -which bridges the hammer-posts at their upper extremities— the upper section of the arch-rib, and the upper rib-braces with their solid abutments are all framed together with tenon-and-mortise joints. The main arch-rib is further reinforced by moulded laminations, with butt joints arranged so as to overlap well those of the rib itself. These laminations are secured to the rib by wooden pegs. Both the common rafters and the ashlaring are concealed behind the plastering between the bays. Above the collar is the typical Western form of waggon ceiling which has already been described.

This Exeter roof is remarkable, as much for its details of similarity to that of Westminster Hall, as for its many points of variation. The latter has now to be considered to bring this chapter to its conclusion.

The roof of Westminster Hall, drawings of which are given in Figs. 90 and 91, among other claims to distinction, is easily the largest and the most elaborate example

of its kind existing. The Ilall itself was built for William Eufus, and at Whitsuntide, in the year T099, he held Court in the Palace of Westminster, as it was then styled.

We have no exact knowledge of the original roof of the Hall, but it is conjectured that it was in double-aisled form, with wooden posts to the floor, in the manner of York Guild Hall. ConsuM ring the standard of roofing science at the date when the Hall was built, this form of construction is the onl\ one which can be imagined for a vast hall, 23S feet in length by 68 feet in span.

It was in 1394, in the reign of Richard II, that it was decided to renew the roof, and in that year, John Godmeston, Clerk, is appointed " to cause the Great Hall in the Palace of Westminster to be repaired." Hugh Heiiand, the King's Master Carpenter,

Was this article helpful?

0 0

Post a comment