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io | Detail of joint between primary post and twin beam, scale i:io. The beams are held together and to the primary posts by means of appropriately long screwed bolts. Where the use of lock nuts was not possible anchor bolts were used. The superimposed beams were secured with dowels to prevent lateral movement. The roof beam of the canti-levered section is mortised 25 mm into the primary posts and held secure with screwed and anchor bolts.

11, below | Isometric from roof ridge over south-side high-level windows. From top to bottom the roadside roof surface is built up as follows: natural slate covering of 510 x 305 x 6 mm boards on 38 x 25 mm laths, insulation sheeting, 50 x 32 mm counter-lathing, 50 mm heat insulation, vapour barrier, 2 layers of 15 mm plywood boarding, 250 x 75 mm rafters, between these 9.5 mm gypsum ceiling baseboard in metal frame.

The roadside pitched roof is formed by 250 x 75 mm rafters that stretch from the ridge purlin at the top to a 150 x 150 mm inferior purlin that follows the curve of the masonry wall. The differing distance between the ridge and inferior purlins gives rise to an arched roof surface, which creates a particularly attractive interior. Under the inferior purlin runs the already mentioned roadside row of soundproofed windows.

To allow for the slow drying and shrinkage of the timbers adjustable connections had to be used. Although the wood was kiln-dried the three months available were not enough to ensure adequate stability. Consequently allowance had to be made for fissuring, twisting and splintering. For this reason the particularly sensitive rafters of the pitched roof had, for example, to be joined to the two-layer plywood roofing, designed to accommodate any shearing stresses that might occur. During the installation of such components as windows and outer doors the anticipated changes were also taken into account. In the case of all the timber connections the loads involved have been accommodated by appropriate profiling of cross-sections. Because bolts alone can only be used as positioners to hold parts together structural engineers and architects together developed a screwed steel bolt system comprising transverse anchor bolts and cover plates, which proved both statically satisfactory and eye-pleasing. On account of the corrosive nature of green oak all these connecting parts are of stainless steel. A few examples of wood joints are shown here. They show that solid wood cross-sections do not require hand-crafted or industrial nail-and-plate connections and that with the aid of modern technical methods novel and eye-appealing design details can be developed and executed.

12 | Exploded view of beam joint. Rod end anchors were used to connect into longitudinal members, and flush dead end anchors when bolts passed through to the hidden side of a member.
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