The great architect Donald Insall on saving Windsor Castle, refurbishing Westminster and how buildings change throughout their lives

‘Buildings are so very much like people,’ says Sir Donald Insall. ‘They all have their own characters, their own strengths and weaknesses, their own message, their own background in terms of the influences that have made them. People change throughout their lives – so does a building.’

Born in 1926, Sir Donald began his career when conservation was regarded as ‘a bit odd – not part of everyday planning’. After architectural training at Bristol and a scholarship to the Royal Academy School, he won the Lethaby Scholarship from the Society for the Protection of Ancient Buildings. That fired his imagination, but, in the late 1950s, an interest in old houses seemed antiquarian. ‘Nice to meet you, but when will your father be coming?’ asked the builder on one early job.

After working for Claud Phillimore, much occupied with the reduction of large country houses to fit the diminished scale of post-Second World War life, Sir Donald launched his own office in 1958, from his flat in Lyall Street, SW1. His father and then his wife, Libby, a lawyer, did the accounts.

It was a far cry from his practice today, in which he has 100-plus colleagues – ‘a lovely bunch of folk, all so capable and so busy’ – across several offices in London and choice provincial towns. The spirit, however, stays the same: that of a family, united by a common purpose and enthusiasm.

‘Our first big job,’ Sir Donald recalls, ‘was a report on Kedleston Hall. I used to take a scooter on the train, hop off at Derby and go to the hall, where I was met by the butler and the dogs. Once or twice, [owner] Lord Scarsdale came on the back of the scooter for a ride around the estate.’

Like other country houses then, Kedleston had suffered years of neglect; in the 1970s, it would go to the National Trust. Sir Donald was employed on several houses owned or being considered by the Trust; a call would come, perhaps on Sunday morning, from James Lees-Milne, seeking help on The Vyne, Croft Castle or Speke Hall.

These, surely, were bleak years for architecture: country houses that didn’t find a saviour were all too often demolished, as were terraces in cities. Modernism, the style of the moment for new buildings, left much to be desired, but Sir Donald had known nothing else and he was entranced.

‘It felt delightful, exceedingly busy, totally encompassing, and I loved it. The whole world was a mixture of postwar depression and elation it was all over, with a determination to put it right.’

Over six decades of practice, which are the most memorable buildings to whose subtle whisperings he has lent his ear? He hardly likes to answer. They were all friends; it’s as if selecting one would offend the others.

Reluctantly, he names 17th-century Chevening House, left to the nation by the last Earl Stanhope in 1967 and now the official residence of the Foreign Secretary. A box-like attic storey had replaced the hipped roof and the outside was covered in grey tiles. The attic’s weight had caused structural damage and the tiles, attached to the brickwork with rusted spikes, ‘were coming off like leaves in autumn’. It was decided to remove ‘the box’.

The splaying walls were stitched back together with a reinforced-concrete beam; a skin of hand-made bricks replaced the tiles and pilasters added in the 18th century were given a pediment, uniting the main block architecturally with its flanking pavilions.

‘It was typical of a complex and delightful job,’ comments Sir Donald. ‘So interesting and so challenging.’ An oblique compliment was paid when, following a royal tenancy at Chevening, The Prince of Wales added pilasters and pediment to Highgrove.

After the fire in 1992, Windsor Castle presented ‘a unique case. It ranged from complete restoration of a very exacting kind to renewal in spirit. As well as keeping things as they were, or putting them back as one thinks they were – which is chancy and not the main aim – we had to find new solutions to parts that had been irreparably destroyed’.

Before anything else, the building had to be stabilised. Walls were sopping from the volume of water used to douse the blaze; water was trapped in the stone by plasterwork that was often historic. With the consent of English Heritage, the walls were opened up to fresh air and dehumidifiers.

During work, new discoveries were made. In the Great Kitchen, it was found that, in the 1820s, Sir Jeffry Wyatville hadn’t taken out the medieval oak timbers, but had encased them in softwood to make them appear more Gothic. Clearly, the old timbers should be retained if possible: they were and ‘given fresh courage’, as Sir Donald writes in his new edition of Living Buildings, ‘by traditional methods of scarfing-in new oak, backed where necessary by invisible steel strengthening’. Wyatville details were reinstated.

Now, Donald Insall Associates has another daunting mission, as conservation architects for the Palace of Westminster. The practice has already begun, renewing Barry and Pugin’s encaustic tiles and repairing the great hammerbeam roof of Westminster Hall. Once politicians can look beyond Brexit, plans will have to be made for the huge project that will renew the building’s collapsing services and repair its structure.

‘It will be a question of retaining everything that makes it wonderful, yet facilitating its continuing usefulness and practicality,’ he says. ‘The real difficulty is knowing what has to be provided for.’

This means looking decades ahead. Will there be changes in the House of Lords, for instance? Whatever happens, it will be ‘a fascinating job,’ says this indefatigable 93-year-old. ‘They’re all fascinating. That’s why we love what we do.’

‘Living Buildings: Architectural Conservation, Philosophy, Principles and Practice’ by Donald Insall was reprinted in 2018

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