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Brian Morton discusses
the renovation of
an unusual conservatory


‘SUPPORTING COLUMNS’
RESTOIUNGA CAST IRON
CONSERVATORY
The conservatory at Broughton Hall near liverpool is built as an addition onto the side of a Gothic style house, builtm 1860 for Gustavus C. Schaube of Hamburg, a prominent Liverpool merchant.
At a dinner in 1868 he entertained Thomas Henry Ismay and a Mr Wolfe, Schaube’s nephew. Over a game of billiardsitwasagreedthatiflsmayagreed to have ships built by Harland & Wolfe then Schaube would fmance a company called the Oceanic Steam Navigation Company, which latterly became the White Star Line and then the Cunard White Star, a very famous shipping line out of Liverpool. In 1868 the first ship built for Ismay was named Broughton, a 580 tonne vessel which plied for Ismay until 1875 and was finally wrecked in
1902.
The significance of the information given above is that I believe that this conservatory is unique and was probably built in the Shipyards as a ‘one off for Mr Schaube, probably between 1870 and 1880.
When I was asked by the Victorian Societyto look at the conservatory, it had been suggested by previous engineers that it was in a state of collapse and perhaps demolition was the only option because of the expense of carrying out a verydetailedexaniinationassociatedwith preparmgafullspecification. Fortunately, Helen Hutchinson of the Conservation Departmentforthe Cityof Liverpool, had the foresight to realise that perhaps it could be restored, and approached Edward Distelkamp, an expert on the history of conservatories, who asked me to look at the conservatory on behalf of the Victorian Society.
It was with some excitement that I first visited the conservatory (top photograph). Originallyitapparentlyhad a semi-circular dome at its top and the sloping roof was glazed onto the existing rafters which still remain. Internally, the very thin structural columns helped to create the feeling of space and light (bottom photograph).
Weightman & Bullen, who act as architects for the owners of the Hall, had originally felt concerned for the rusting of some of the external columns; indeed some had previously been replaced; and also there were hair cracks to the thin
internal columns supporting the cupola. Engineers called in by them had recommended averymuchmore detailed investigation and implied that it was almost inevitable that demolition would be the most cost-effective option.
Initially, looking at the condition and stability of the structure, it was apparent that the long sides were subjected to thrust from the rafters without there being any ties. Lining through these long sides by eye there was in fact very little distortion. When I looked at the detail at eaves level, it appeared that there was a verysubstantialtimberwallplate running around the periphery of the building linking each of the panels of the iron frame. This helped the stability considerably while the plan shape of the building was also of considerable help.
Ifelt that this structurewasworking as do many structures of its type, where the load is being spread around the elements of construction and you could probably knock out one of the elements without there being a complete failure because the load would redistribute itself. Inspection of the internal columns showed that one of them clearly was crackedandafurthercolumn hadpossible cracking; thus the structure was satisfactorily holding itself together with one of the columns in a effective ‘failure’
mode. If, then, we repaired the column and sorted out the rusting external columns, the conservatorycouldbe safely restored structurally. The filigree brackets at the column heads also of course helped the stability. -~
The intriguing factor associated with the construction is undoubtedly the filigree work which is applied both internally and externally as infill over the arches just below eaves level, because this encloses glass (photograph 3). All of the ironworkandthefrieze directlyabove it externally appeared to generally be in good order; the problems occurred with the column heads and the external ironwork to the external columns.In carrying out the investigation we were influenced by a feeling that the walls must be constructed as two skins; of course, the implication of this was that the columns were cast in semi-circular form.
We were able to take off a section of column externally (photograph 4). To our surprise this revealed what can only be described as a softwobdtimberbauen 45mm thick by 100 mmwide (the width of the column). To this was fixed the timber window frame.
This opening up, of course, clearedup the problem of how the glass had been inserted between the iron panels over the window, in that the structure must have been erectedwith much temporary support as a timber framework which was then clad with iron. It must have been intriguing to have been dealing with a structure which was intrinsically unstable until the iron cladding had been added. I believe that the addition of the glass will in itself have added to the stabifity, helpingtheinteractionbetween the various structural components.
After I had made my initial inspection andpassedmycomments backto Edward Distelkamp, he lobbied English Heritage withthe result that the main building and the conservatory were lifted from Grade II to Grade 11*. This of course had the effect of making the conservatory grant eligible, andlampleasedto saythata4O% grant was eventuallymade available from English Heritage.
Clearly, with a structure of this kind it is important to establish a methodology for carrying out the work and to make sure the contractor allows within his price for dealing with the form of construction. Fulltemporarysupporthas
Above: the conservatory as originally seen by the author.
Below: very thin structural columns giving a sense of spaciousness.
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