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Windsor Castle continued
| Capps and Capps, a specialist contractor based in Wales near Hay on Wye, felled the timber and constructed the heavy ceiling structure. They obtained the timber from a nearby managed estate and
used 350 of the one hundred year old oaks to construct the ceiling. The form of the ceiling structure is Gothic in principle and meant to represent a hammer beam roof structure. The constraints of the new steel roof limited the pitch to something
less than the 45-55° that one would expect for a hammer beam roof structure. The fourteen trusses of this roof are immensely complicated. The two halves of each truss are symmetrical about the ridge line and each half is itself divided into two
parts: the main centre arch springing towards the ridge and the lower arch coming down to the corbel on the wall. At the junction between the two is a pendant post from the bottom of which a large boss hangs down into the hall and contains concealed
lights. At the top of the pendant post, the point around which the whole structure works, four different timbers have to be accommodated: the top chord or principal rafter coming up from the wall plate and then going on up to the ridge; the pendant
post purlins coming in from east and west, and of course the pendant post itself. Each of these members had deep mouldings run in them so that shrinkage cracks would form in the shadows of the moulding and each of these roll mouldings, so as fat as
rainwater pipes, had to run into each other where the members |
met each other. All of the joints had to be housed. At the top of the pendant post the joint was described as 'central pegged stop end tenon with reduced pegged bridle-bearing and
face-scribed housings to purtins with haunched top tenons'. Most hammer beam roofs fail by the horizontal thrust at the eaves pushing out the tops of the wall. The top ridge joint opens and the ridge itself drops. in order to give some continuity of
structure at the ridge we introduced an elbow joint on the underside of the junction of the principal rafters. it is a large and very heavy, curved piece of timber and the curve cannot be cut out of a straight section; the curve must be grown if the
drying grain is not to split the piece open. The means of fixing the elbow was described as 'two folding wedges in a double ended stop played and tabled scarf with under squinted transverse key and four face pegs'. in order to test the strength of
the joint, we requested that Southampton University set up a jig and using a purpose made joint supplied by Capps and Capps undertake pull out tests. Timber pegs and loose tenons were also checked for shear capacity.
Although the original programme for completing the roof anticipated a six month period, the complexity of jointing the structure actually took two weeks short of a year. |
In the ante-room to St George's Hall, glulaminated oak has been used to create the eight columns and the curved ribs which rise from them to create a lily-like structure with a glazed roof
lantern surmounting the whole. This represents a tremendously complex geometrical form and most of the cutting was done by computer controlled routers.
The architect produced a similarly complex geometry for the ceiling structure of the new chapel. The flat fan vaulted ceiling is again constructed of glulaminated oak ribs. Each of the six bays of the chapel, which is not a big room, has over a
thousand different pieces of oak built into it. Taylor Made joinery, who undertook the work, relied heavily on computer aided design to produce the finished form.
The Queen and Duke of Edinburgh's fiftieth wedding anniversary and the fifth anniversary of the fire was 20 November 1997. This was the completion date for the restoration project. On 17 November the Queen held a reception in St George's Hall for
all of those contractors, craftsmen and consultants who had been involved in the project and expressed her deep gratitude for returning Windsor to her in all of its newly established glory. The project had taken five years, resurrected the skills of
many craftsmen, and cost £36.5 million. |
Bibliography
1. In-house report.
Gifford and Partners 1994. Windsor Castle phases 3 and 4
Fire Restoration - Materials Identification and Assessment Survey
Report No 6457/11/RO6. August 1994.
2. In-house report.
Gifford and Partners 1994. Report on the structural proposals for the repair of the Mediaeval Timber roof over the Royal Kitchen at Windsor Castle following the fire in November 1992.
Report No 6457/5/R.01. March 1994.
3. Unpublished report.
Hutton and Rostron.
4. Book.
Nicholson Adam 1997.
Restoration: The Rebuilding of Windsor Castle published by Penguin Books.
5. CINTEC anchor by Cavity Lock Systems Ltd. Factory Road, Newport, Gwent NP9 5FA. UK. |
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