Sheila Stainton, who has died aged 89, was a textile conservator and in 1977 became the first housekeeper for the National Trust, responsible for the care of the organisation’s 150 historic houses. Her name is indissolubly linked with The National Trust Manual of Housekeeping (1984), of which she was co-author. The first edition became a bestseller, blending the latest conservation techniques with country house practice that had been the norm before the first world war and was perpetuated in places such as Waddesdon Manor, in Buckinghamshire.

The manual was written for the NT’s non-specialist house staff, and was equally reassuring to householders who read its practical tips and were put at ease when told to do nothing, just call in a conservator. The first edition of 262 pages morphed into the current authoritative tome of 941 pages, essential guidance for house managers and their assistants.

Sheila’s writing partner, Hermione Sandwith, had been appointed in 1974 as attendant to itinerant paintings conservators at NT houses: she became self-appointed conservation supremo for the care of the NTs chattels. Sandwith recognised that conserving historic contents should go hand in hand with caring for them to a higher standard than was hitherto practised. This entailed training staff and she enlisted the help of Sheila.

The National Trust Manual of Housekeeping, by Sheila Stainton and Hermione Sandwith, was first published in 1984

In 1975 the NT had invited Sheila to supervise a textile conservation workroom at Erddig, in north Wales, not long after the NT had acquired the property. The house was spartan: it was cocooned in scaffolding following the collapse under the building of a shaft from nearby Bersham colliery; the former owner lived on site; the contents, from ducal to rag-man quality, were grimed with coal dust and 120 volunteers had signed up to help. They were a diverse crew, number ing the wives of tenant farmers alongside assertive and highly skilled needlewomen. There were cushions, chair covers, pelmets, valences, counterpanes, linen, blankets, vestments, liveries, clothes and curtains by the dozen, all stiff with coal dust and heavy to handle.

It is easy to forget that textile conservation is often strenuous, dirty and physically demanding. When Sheila arrived at Erddig, she was allotted a bedroom with a Baby Belling cooker and left to get on with it. Fortunately her sense of humour persisted. Quietly but with tact and firmness she established her authority among the volunteers and in the hierarchy of the house.

She was quartered at Erddig for two years. By 1977 the news spread that the workroom was fun so that in the end there were more volunteers than tasks. The NT then persuaded Sheila to open a second workroom at Dunham Massey, the Georgian mansion in Cheshire.

Textile workrooms were symptoms of a broader revolution within the NT as it accepted responsibility for the care of its houses and their contents. In the early 1970s word had got about that it was failing to look after its collections. The historic buildings staff responded by setting up an advisory arts panel, its members drawn from the art establishment who were concerned at the NT’s perceived laissez-faire. In 1974 St John Gore was appointed historic buildings secretary and charged with bringing professionalism to how the houses were cared for.

A drawing of the saloon at Erddig, north Wales, c 1849. Photograph: National Trust Images/John Hammond

By the close of 1977 Sheila had been appointed the NT’s first housekeeper and a chrysalis manual of housekeeping was circulated within the organisation. Throughout those strenuous years Sheila always seemed to have time to listen, while her demeanour engendered in those around her a mysterious and tranquil joy in their work. To Sheila people signified as much as, if not more than, the houses. When asked for her favourite NT property she responded with the names of the staff. Unsurprisingly Sheila’s part-time job as housekeeper rapidly became a full-time position.

The present-day saloon at Erddig, north Wales, is a testament to Sheila Stainton’s textile restoration skills. In 1975 the NT had invited her to supervise a textile conservation workroom there. Most of the fabric she found was stiff with coal dust. Photograph: Andreas von Einsiedel/National Trust Images

The original manual gained an international reputation. In Britain, Europe, the US and Australia, Sheila became a popular public speaker. Further recognition came when she was awarded the medal of honour by the European Castles Institute. When the Sandwith & Stainton manual was superseded in 2005-06 by a larger publication, the NT paid tribute to the authors by retaining the title.

Sandwith retired in 1985 and Sheila succeeded her as deputy to David Winfield, the NT’s first surveyor of conservation. They both retired in 1989. By then the organisation boasted specialist conservation advisers on sculpture, paintings, textiles, paper, furniture, metalwork, ceramics and so on.

Sheila was born in London, the youngest of four children. Her father, John, was a lawyer who worked at the Parliamentary Counsel’s office; her mother, Bertha, came from the prosperous Scottish Dewar family. Sheila left school at 18 and took a housekeeping course with Westminster city council. From an early age she had enjoyed needlework, inspired by her paternal grandmother.

From childhood Sheila had made – in her own words – “shapeless dolly clothes” and in London she advanced by taking dressmaking lessons. She then embarked on a three-year course, training as an occupational therapist. Her first job was at the British Legion village, near Maidstone. When Sheila’s parents retired to Scotland, she followed, taking a job with Midlothian county council.

Her first assignment at the NT was formidable: the repairs to a 19th-century state bed at Castle Coole, in County Fermanagh; when Sheila rose to this challenge, other tasks followed.

As Sheila’s career with the NT closed, another opportunity cropped up. Sybil, Lady Cholmond- eley had learned about Sheila’s skill and in 1988 invited her to Houghton Hall in Norfolk. The following year, however, that grande dame died and Sheila moved to live in Aldeburgh, Suffolk.

She was delighted when the present Lord (David) Cholmondeley asked for her help in preparing the house and collections for building work, rewiring and plumbing.

Sheila was well qualified for a task that called for arduous physical work as well as diplomacy. It says much that she described the experience as a “golden retirement job”. Both house and the household won her heart, and she continued to advise at Houghton until 2005.

In retirement-proper Sheila had more time to enjoy her family and friends. Music at Snape afforded her enormous pleasure, the more so because she supported new talent through her Cedar Trust.

She is survived by four nieces and three nephews.

• Sheila Stainton, conservator, born 11 August 1929; died 20 July 2019