The Aviary, Cobham Hall
For seven Sundays in October and November 1992, archaeologists undertook the clearance and recording of The Aviary in the grounds of Cobham Hall. Thanks are extended to the Westwood Educational Trust and Wisell, Wade and Postin's Architects, for allowing access and the permission to undertake this work. Thanks also to my hard working colleagues David Bacchus, Terry Smith and Rachel Harrison; and to Pauline King, Archivist of the Cobham Hall Heritage Trust along with staff of Cobham Hall School for their interest and information.
The grounds of Cobham Hall contain elements of the Elizabethan deer park, remains of the seventeenth century formal layout and of Humphrey Repton's work of c1800, as well as several garden buildings and follies. The structure known as 'The Aviary' is attributed to Samuel Lapridge, a pupil of Capability Brown. This flint and brick structure almost certainly started its life as a greenhouse, being converted to an aviary c1799 and later a summer house; being used as such until the 1950's. It is now in a derelict condition, its roof has collapsed and the flint facade tilts outwards by as much as 30cm. Restoration and conservation work are being undertaken in the grounds of Cobham Hall, and as part of this exercise it is hoped to push the flint facade back into place securing it with stainless steel tiles. The joinery will also be renewed and bricks, identical to those used in the original structure, will be made as necessary.
Presumably in its eighteenth century one "room" greenhouse phase 'The Aviary' would have had a glass roof as well as a glass front facing south. With the addition of the flint facade to the original brick structure the area was divided into three by the insertion of timber partitions. It is probable that the central part of the roof, over the larger middle bay, was sloping; flat roofs existing either side. The central pitched roof had a slate covering, the flat areas being roofed with lead and draining into a simple box gutter at the rear.
The presence of the lead roofs perhaps explains the dilapidated nature of the building. Sometime in the last three or four decades the lead may have been removed (stolen?). This removal would no doubt result in some slates of the pitched roof being dislodged. With the process of time further slates would fall, the supporting timbers rot and come crashing down. Gradually the weather continued its work creating cracks in the walls. Leaves, weeds and rubbish accumulated, perhaps as much as five or six tons being removed during the course of the recent clearance.
Even without the help of documentary evidence it would have been possible, just by using basic archaeological "laws" and common sense, to realize there were three phases of structural development. As built in its greenhouse phase, the structure had brick walls to the north, east and west forming a rectangle 9.90 by 4.50 meters externally. The structure cut into sloping ground had terrace walls to east and west retaining the slope. The south face would have been glass; possibly within the wooden framework used for the first partition (see below).
It seems probable that the whole floor of the greenhouse was paved with ceramic tiles on a sand bed. The pre-structure topsoil had been removed and the sand had been laid on natural brick earth.
The drastic alterations undertaken when the structure was converted to The Aviary included the addition of the flint facade and the insertion of timber partitions. It is probable the timber floor in the central bay, and the laying of a stone slab floor in the eastern and western bays took place in this phase. The facade of unknapped flintwork has a somewhat overpowering effect when first seen for its whiteness is in total contrast to the red brickwork and greenery around. The facade is unusual not only in the material used, but also in the way it has been constructed, there are three, rare, flint arches side by side giving access to the individual bays. It is of course the difficulty of constructing arches in flint which makes them so rare.
The timber floor, supported on joists and four dwarf brick walls, saw the complete destruction of the attractive ceramic tile floor in the area of the central bay. In the eastern and western bays a stone slab floor on a mortar bed was laid directly over the tile floor. The latter was still visible in one area of the western bay where a slab has been removed, as well as on either side of the central bay.
The timber partitions of this second phase consisted of large frames 3.50 meters long by 3.95 meters high. The wood was extremely well preserved and originally painted pale blue or pale green, perhaps a preservative rather than a paint. Within each framework it was noted that there were hinge indents, mortise holes and the frame cut so as to take glass. Part of one hinge, along with a metal and leather surround around one mortise hole survived. Originally two doors existed within each frame. It is not possible to say whether these doors were removed when the frameworks were first used as partitions or later when the third phase walls were inserted. This evidence led to the realization that both partitions were originally constructed for another purpose. The arrangement for the use of copious amounts of glass, plus their dimensions suggests that originally the frames were constructed as the front of the greenhouse. Each frame would have reached from the side walls to the stone step into the central bay, with enough room for a double doorway centrally placed. A vertical bolt hole on the north (inner) side of the central step could have been for this postulated door; the step may have originally been set at a lower level flush with the tile floor.
There are however two arguments against this theory. First it would mean there were five entrances into the greenhouse, four single doorways through the surviving frames and a postulated double door. This seems excessive to say the least given that the total width is less than 10 meters. However, the internal design of the structure and the need for ventilation may have dictated the arrangement. Secondly the two brick pillars in the south face, behind the central flint arch, have the look of being the same as the brickwork of the phase 1 walls. If of the earliest phase their presence would effectively block light for about a meter of each frame, in which case there would be no point in making a provision for so much glass. However, the pillars are not definitely of phase 1, and structurally they make more sense as phase 2 additions, constructed merely to give anchor points for the relatively thin flint facade.
Four large iron pivots, those on the west behind later wood paneling, showed that the phase 2 double door opened inwards. Rusty iron work below the lower eastern pivot is perhaps indicative of an earlier pivot arrangement or door stop. A vertical hole for a door bolt could be seen on the south (outer side of the step, presumably for this door.
Each side bay supposedly had birds flying around; the central bay being for spectators. It is assumed wire was stretched between the frame openings, but unfortunately there is no evidence for this arrangement. It would perhaps hardly be worthwhile to remove any wire when the later partition was added, whereas glass could conceivably have been used elsewhere. Reuse elsewhere might also explain the absence of the doors from the framework. A third suggestion is that the birds did not fly free but were kept caged, and that the openings within the wooden frame had neither wire nor glass.
It is possible that the insertion of the timber and stone slab floors is third phase rather than second, but in view of the massive reconstruction taking place in phase 2, it seems far more likely that both types of floor material are of earlier rather than later date. However, it is always possible the timber floor was renewed, perhaps more than once during the relatively long period of use c1799 to c1950. Four planks and several joists survived in relatively good condition.
The third phase saw the conversion to a summerhouse with new partition walls. Within the central bay timbers were nailed to the phase two frame and vertical wooden paneling attached. Only a few lower fragments of this paneling survived, except on the west side of the central door where panels survived more or less full height. In each side bay a plaster surface was attached to lattice work.
The differential survival of wall paneling, joists and floor planks within the central bay was quite surprising. Assuming none had been removed for use elsewhere it was an excellent example of how differing decomposition conditions can exist within a small area. The remnants of the door and window frames probably also date from this phase.
Summary
It seems that all four stages of the life of The Aviary can be identified in the archaeological and architectural remains. The greenhouse by the brick walls and tile floor. The Aviary itself by the construction of the flint facade, the well preserved first partition framework and probably by the timber and stone floor and, presumably, the vanished slate and lead roof. The third construction phase saw the insertion of more solid partitions, and probably the visible door frames. The last phase being one of dereliction. However, a fifth phase of reconstruction is about to begin.
Alan Ward.
January 1993.
Note to KAS members
The Cobham Hall Heritage Trust is undertaking worthwhile conservation work of both buildings and landscape. Hopefully the KAS and its members will give what support they can. Any donations to the Cobham Hall Heritage Trust I'm sure will be gratefully received; C/O Sue Anderson, Development Director, Cobham Hall, Cobham, nr. Rochester, Kent. DA12 3BL.