Conserving Stowe

One of England’s grandest country houses, Stowe narrowly escaped demolition and has benefited from a preservation trust. It has now undergone major conservation works.

The library ceiling on completion.

Stowe was developed in phases from a 13-bay brick house, designed for Sir Richard Temple in the late 17th century by William Cleare (Wren’s joiner and the builder of the great model for St Paul’s Cathedral). Successive generations developed it as a palace for entertaining, set in an exquisite and important landscape garden of vistas, follies and temples.

In the 18th century the house was remodelled by Vanburgh and Kent, and subsequently extended and embellished by Earl Temple, who lengthened the house and modified the north and south fronts. He consulted many architects, but clearly had a strong hand in the final designs and brought in continental craftsmen for the interiors. In the 19th century, his grandest descendant, the Duke of Buckingham, collected and embellished extravagantly for a visit by Queen Victoria in 1845. But he had overextended: much was sold in a great sale in 1848 and fortunes continued to dwindle.

The family finally sold up, to a demolition contractor, in the 1920s, but fortunately Stowe was saved by an enterprising group of individuals who bought the house and park, and adapted them for a school. Stowe School employed Clough Williams Ellis as its architect and master planner, and the house was repaired, and new buildings were added with some tact and care.

Maintaining the house and its extensive gardens became a burden for the school, despite excellent teaching based on the buildings and landscape, and the enthusiasm of hands-on teams of boys and staff who helped to maintain the gardens. In the 1980s the National Trust negotiated to take on the care of the gardens, and in 1997 the Stowe House Preservation Trust (SHPT) was set up to repair and re-present the house for the benefit of the nation.

In 1999 SHPT was awarded a major Heritage Lottery Fund grant and Purcell was appointed as their architect. We were given a sizeable box of research papers and reports commissioned by the trust and largely undertaken by Inskip and Jenkins, who had looked after Stowe House and Gardens for some years before. This included a four-volume conservation plan, folders of early illustrations of the house and detailed research on the pathology of the building.

The HLF grant had been offered for repairs to the north front. The conditions on which the grant was offered included increasing the number of visitors; improving physical and intellectual access; removing car parking from the forecourt; and generally improving the appearance and approach to the house.

The north front, some 400 feet long, was largely finished in render. This had cracked and failed in many places, letting water into the soft red bricks underneath. We began research to identify an appropriate specification for a replacement render, bearing in mind the trustees’ requirement that it should not need maintenance for 75 years, and thus a limewash finish would be inappropriate. We did find small samples of what we believed to be the original lime render on the rear of a parapet. When analysed it was found to be made with a mildly hydraulic lime and a local sand. Historic research told us that this render had lasted some 90 years or so after it was first applied, was replaced in the 19th century using a Roman cement, which failed, and was in turn replaced with another cement render by the school in the 1930s. We set up tests and found a sand quarried at Finmere, formerly part of the Stowe estate, only three miles away. Mixed with lime, it created a pleasing cream-coloured render that was specified for all subsequent work.

Other challenges in this project included finding spaces around the site for replacement car parks, applying poultices to brickwork to remove harmful salts before re-rendering, and researching local stone slates for the rear slopes of the colonnade roofs (and finding experienced roofers who could lay them neatly). We went to Port Lympne in Kent to make copies of the herms for the outer north front walls, and we recreated the urns for the parapet of the main house from a Country Life photograph of 1914.

Our next contract, again lottery funded, was for the south front and the Marble Saloon. Work included removal of a 1960s aluminium roof over the central block to reveal the dome, and replacement of the lead roof coverings underneath. The dome is supported on timber beams, which were found to be quite badly rotted and had to be repaired in situ.

The stud walls surrounding the saloon supported an entire ring of cast-iron water tanks, some dating from the nineteenth century, and others placed there by the school. There was potential for catastrophic damage should the tanks have leaked into the timber and plaster walls. The HLF grant enabled the school to excavate for and provide new water tanks in the grounds. A contractor was found to unbolt the tanks carefully and remove them piece by piece.

Externally we undertook stonework repairs using a Bath stone, sympathetic in colour to the many local stones used by the original builders. We carried out experiments with different strengths of diluted copperas (an iron sulphate) to stain the stone. This was used in the 18th century to give the masonry a golden colour and perhaps to disguise the differences in stones used. We used it to tone down the new sections of stone. Our philosophy was to replace any stone that was in danger of crumbling away or was dangerous, and to ensure that the designed crisp lines of the classical mouldings and architectural detail were maintained. Some of the original work had been hastily done, with stone only 15 mm thick and not always adequately fixed back on the brick or rubble cores.

Internally the Marble Saloon was scaffolded above the cornice, and the decorative plasterwork was cleaned, repaired and limewashed. The triumphal processional relief running around the base of the dome was damaged, and we replaced missing limbs, spears and facial features. We made sure that the trap door giving access to the cornice, which had formerly been used regularly by daring schoolboys, could be kept securely locked.

The work was finally finished when classical statuary was returned to the wall niches. The trust acquired eight modern casts of classical figures from Germany and commissioned four copies of the Atheniennes or torcheres which originally stood here. The lanterns over them all were replicas made to match those illustrated in a contemporary watercolour by the artist Nattes.

Work to the south front included masonry repairs to the Western Pavilion and the adjoining State Dining Room, followed by reroofing the State Library, and internal repairs and redecoration of its ceiling. In the early 20th century this roof had failed, its trusses were removed and felt was laid on boards. Not surprisingly, it had failed on many occasions, damaging and loosening the internal plasterwork of the library. Fortunately, we were able to replicate the roof trusses on the matching pavilion to the west, and recover in lead before carrying out extensive repairs to the plasterwork. During this work we found many traces of gold leaf. A decision was made to reinstate the original decoration to spectacular effect.

Re-presentation of the interiors continued. The work included the careful cleaning and conservation of Valdre’s decorations of the Music Room, the recreation of the decorative scheme and imagery in the Egyptian Hall, and work to a smaller Blue Room, which was hung with new silk damask. Conservation of Kent’s ceiling in the North Hall was followed in 2019 by redecoration of the walls, and a new stone floor was laid to replace 1950s terrazzo tiles. The final and magnificent addition, the commissioning of a bronze replica of the Laocoön sculpture which stood here in the 19th century, has reinstated the grandeur of the entrance.

All our work has been supported by detailed historical research, carried out either within our own team or alongside SHPT staff. The approach taken to uncovering and documenting the painted decoration schemes has followed analysis by Patrick Baty. An expert advisory panel has given considerable help, and critically reviewed all proposals.

An early decision was made to bring back the exterior of the house to its state when completed around 1780–1800. To that end the trust commissioned Cathy Fisher, a former colleague at Purcell, who now lives in Los Angeles, to spend many months in the Huntington Museum there, researching building records. Her work, which informed our approach and specifications, is now held by both the SHPT and the National Trust. Each project has involved detailed archaeological recording, and the new information and reports from historians, archaeologists and conservators are extensive.

All of the contracts have included work to meet the practical needs of the trust’s tenants, Stowe School. These have ranged from a careful upgrade of heating, wiring, fire protection and other systems, to repairs to joinery and the strengthening and repair of floors. At an early stage we installed a lift from the ground floor to the piano nobile. We provided a welcome reception for visitors with educational materials, later replaced and remodelled with a further HLF grant, to adapt the basement beneath the Marble Saloon.

Programming opening-up works in school holidays; avoiding noise during exams; planning the contractors’ working site for deliveries and access without risk to school pupils; and designing scaffolds in the Marble Saloon and North Hall to give access for repairs while allowing the school and its visitors to function underneath: all of these have involved detailed negotiations with the school, the trust, the events team, consultants and contractors.

This article originally appeared in Context 166, published by the Institute of Historic Building Conservation (IHBC) in November 2020. It was written by Jane Kennedy, a senior partner with Purcell.

--Institute of Historic Building Conservation