PERIOD FEATURES 4: PLASTERWORK; Cornices, friezes and ceiling roses were a feature of most Georgian, Victorian and Edwardian houses. Then, insensitive developers moved in. But quality restoration is available - and affordable - writes Lesley Gillilan
THE LIME stucco ceiling in the Little Drawing Room at Uppark, the National Trust's 18th-century mansion in West Sussex, features a dynamic sunburst motif with an Apollo mask at its centre, framed by a swirling trellis of fruit, foliage and flowers. Finely executed in white relief against a background of pale duck-egg blue, it is a beautiful piece of architectural embroidery perfectly in tune with the rhythm of its historic setting. But the decoration is not, strictly speaking, authentic. The design itself is original, as are some of the hand-moulded details, but the majority of the workmanship is contemporary.

During the fire which raged through Uppark one night in August 1989, this and other examples of the building's original ornamental plasterwork were consumed by the flames. "The house was open to the sky," says Peter Pearce, the project director who took responsibility for the building's painstaking interior restoration. All that remained of the glorious ceilings lay in thousands of pieces, scattered among the charred wreckage.

Over 12,000 fragments of moulded plasterwork were salvaged. A team of master plasterers was brought in to work these relics into careful reproductions of the destroyed decorative schemes. The Little Drawing Room's mask of Apollo, for example, is original; but the sunburst radials are new - as are many of the intricate leaves, urns and "arabesque ornaments" which flow across the remade surfaces of the building's five restored ceilings.

It was, says Peter Pearce, one of the most complex and difficult conservation tasks the National Trust has ever undertaken. The majority of Uppark's original ceilings had been made by hand-modelling lime stucco in situ, or moulding wet plaster into shape as it dried. This practice disappeared in the mid-19th century when the use of pre-cast gypsum and fibrous plasters became the norm. Hence, all the skills and processes which went into Uppark's ceilings had to be relearned.

"The work at Uppark exploded the myth that these things cannot be done," says Peter. "It also demonstrated that high-quality craftsmanship is available and within the reach of all homeowners." Few own a home quite like Uppark, but cornices and plaster ceiling mouldings are a standard decorative feature of most Georgian, Victorian and Edwardian houses. Or at least they were, until insensitive developers and home improvers started tearing them down or stemming their flow with thoughtlessly placed partitions.

Modern master plasterers may build their reputations on creamy conservation commissions in the Uppark league (the post-fire restoration of Windsor Castle, Prior Park and Hampton Court Palace were among other recent jobs- to-die-for in this specialist industry) but many of them depend on bread- and-butter trade, replacing damaged plasterwork and reproducing missing ceiling roses in relatively ordinary period houses. In their own small way, these jobs are as challenging and as worthy as the conserving of an Uppark ceiling.

Dulwich House, the home of classical pianist Bryan Ellsbury, is a fine example of the high standard of plasterwork finery found in modest domestic settings. The small Victorian Gothic house was built in 1882 by Ralph Gardiner, the master plasterer responsible for the ornate ceilings inside Dulwich College. To demonstrate the range and virtuosity of his art, he used his own house as a showroom.

"He really went to town on the drawing room ceiling," says Bryan. "There's a bit of everything." Egg-and-dart borders, swags and tails, bows, scrolls, shell motifs, wolves' heads, flowers, tassels and acanthus leaves - all typical of the Victorian plasterer's repertoire - are worked into a rich feast of cornices, corbels, friezes, panel mouldings and a coved ceiling. There's even a plasterer's coat of arms and a motto: "Let Brotherly Love Continue".

When Bryan moved in ten years ago, the exquisite Gardiner ceiling was one of the few original features of the property that did not need to be revived after a century of home improvements. "The rest of the house was done out in purple plastic and finished off with pink, fluffy shag pile, but the ceiling was immaculate," he says. Though fine plaster mouldings look as delicate and ephemeral as wedding cake icing, the material is extremely robust. It is, however, vulnerable to damp, dry rot, sagging and cracking (either due to age or associated structural faults), wilful destruction and, more commonly, over-painting.

When Victorian homes were lit by gas and oil lamps, the white ceilings bore the brunt of rising smoke and smut, and the quickest way to freshen them up was to slap on layer after layer of distemper. Built up over years, and covered more recently with glosses and vinyls, the paint eventually blurrs and obscures the plaster detail and clogs up the crevices. Even Bryan's immaculate ceiling had suffered in this way. But he has largely resolved the problem by loosening the distemper with water, washing it off with chemical stripper and repainting the surface with a light coat of diluted emulsion.

DIY is the most economical way of sprucing up plasterwork - if you have the time and patience. Conservator Richard Ireland (one of Uppark's saviours) says he once spent nearly 2,000 hours cleaning a 25ft x18ft Victorian ceiling - a job which involved "a lot of picking at old paint with toothbrushes and cocktail sticks". At pounds 10 an hour, this tiresome but simple job becomes unrealistically expensive when using a contractor. But while Richard recommends DIY, he warns how important it is to first find out exactly what you are dealing with.

Most 19th-century plasterwork is supported by a framework made up of narrow laths of oak or softwood nailed to the ceiling joists in close- knit strips, but the fabric of the plaster detail varies. In late Georgian and Victorian houses, gypsum plaster, reinforced with timber, is the most prevalent material. Strong, versatile fibrous plaster - made from gypsum combined with hessian - became more common after it was patented in 1856. But some period plasterers crafted details out of papier-mache or "compo" (paper-based compound). To an untrained eye, they look like gypsum, but if you try cleaning them with water they dissolve.

All plasters are vulnerable to misguided use of chemical cleaning solutions."A lot of damage is done by people who think the job can be done quickly," says Richard Ireland. "Some of the more astringent paint removal materials will make fast work of a cleaning job, but used carelessly they may weaken the plasterwork. In some cases it will just crumble away."

Plasterwork that has already crumbled can be restored. Typically, a damaged ceiling will have lost a couple of petals from a ceiling rose or a section of the cornice "enrichments" - a fleur de lys, Virginia leaf, bird, beast or fruit scroll. The usual method of repair is to use a piece of the remaining detail to make a mould from which new matching pieces can be cast in plaster and carefully nailed or glued into position. "If you've something really special, it's worth making the effort to restore rather than replace damaged plasterwork," says conservation specialist Martyn Watchurst of ornamental plasterers Hayles & Howe in Bristol. "But in many cases it's marginally cheaper to remake the whole scheme from scratch." In some cases, there's no option.

When Candida Gosnell bought her early Victorian house in Bristol, the place had been completely gutted. "The previous owner had ripped everything out down to the bare brickwork," she says. "The house was like one enormous room; there was no ceiling other than the roof." Others might have been tempted not to bother with restoring the lost plasterwork, but Candida felt the house wouldn't work without it. "You probably wouldn't be able to put your finger on what was missing, but it would look awful."

As there were no remnants of the original work, and no guiding references, she was able to exercise an element of personal choice. "It was a question of picking something I liked out of a brochure," she says. That brochure came from Hayles & Howe, one of several plastering firms who offer an off-the-peg range of pre-cast mouldings made to authentic 19th-century patterns. They include plain and decorative cornices (designed to sit at the top of a wall); friezes and ceiling plates (used in conjunction with cornices); ceiling roses; corbels and brackets; columns and capitals; and "miscellaneous enrichments". Designs reflect all the traditional plasterwork idioms from an eight-leaf acanthus ceiling rose with grape ring and a Georgian gryphon frieze, to Tudor strapwork coving and a dentil cornice - a neat row of tooth-like rectangular blocks.

All these standard items are made-to-order from latex moulds. At Hayles & Howe, they are produced in a small, wonderfully messy workshop. Staffed by overalled plasterers, who mix buckets of glistening white splodge and slop it into moulds, the place looks like a cross between a bakery and an ice-cream factory. But its appearance belies the exacting nature of the work. Many non-standard, one-off commissions entail the hand-modelling of individual enrichments in clay before casting. Recent jobs include reinstating ceiling details in a section of Windsor Castle, and originating Tudor-style pictorial panels for a house owned by Sting.

Candida, meanwhile, has enriched her rebuilt house with plain traditional and egg- and-dart cornices combined with urn, fruit and vine scroll ceiling plates. They now decorate the hall and landings, the lobby, one bathroom, the kitchen, four bedrooms and three reception rooms. The whole job cost in the region of pounds 6,000 - about half of which was spent on labour. Hayles & Howe estimates the average cost at pounds 700 per room for the supply and fitting of pre-cast cornice mouldings.

Candida hasn't yet got round to choosing the ceiling roses. "Fixing cornices is a messy job and needs to be done before the house is carpeted and furnished," she says, "but ceiling roses are easy; you can just plonk them up any old time." A good cast, fibrous plaster rose - in an authentic period design and nothing like those sad little pressed plastic things you find in DIY stores - can be bought for pounds 40. Some come with an optional moulding, mounted on to a standard electrical cap, to ensure that the lighting flex dangles correctly from the heart of the flower.

Victorian decorators had a habit of positioning ceiling roses so they lined up with chimney breasts. The idea was to make sure the central light fitting - probably a glass-shaded gasolier - would be beautifully reflected in the obligatory mirror over the mantelpiece. Only purists need to stick to this disconcerting, off-centre approach to roses. In fact, why stick rigidly to tradition? With the introduction of modern materials such as glass-reinforced gypsum and resinous coloured plasters, the medium has never been so versatile, so flexible or had so much potential for precision detail. According to Hayles & Howe, "Any idea, however outlandish, can be expressed in ornamental plaster."