Maintenance
Often smothered with layers of paint, decorative plaster mouldings should in fact be a room’s crowning glory, so learn how to restore or repair these lovely period features
Adding style and proportion to interiors, decorative plaster mouldings vary from simple cornices to highly ornate ceiling centres and other adornments. Early cornices were ‘run’ in situ using mortar or lime putty to fashion a seamless ceiling decoration, sometimes embellished with ‘enrichments’ cast separately in moulds. After fibrous plaster was patented in 1856, decorative pieces were made in the workshop; using a mixture of hessian fibres and plaster of paris cast in a mould and reinforced with timber from behind, these were fixed into position on site.
How to repair
The most common source of damage to plaster mouldings is moisture, says Russell Brewis of Artisan Plastercraft. ‘This can be dampness over time or a water episode, such as a flood or burst pipe. Old plaster can also be compromised by sustained vibrations, as well as damage caused by building work. If there is evidence of damp, water staining, cracks, or detached pieces, it is advisable to seek the guidance of an expert.’
With any issue relating to moisture, the first task is always to identify the source of the dampness and prevent it from continuing before beginning remedial work. Carol Hopkins of the Classic Cornice Company advises letting the plaster dry out and then assessing the damage. ‘If the mouldings have loosened and are pre-made sections, you may be able to refix them,’ she says.
It is equally important to understand the cause of cracking to decorative plasterwork as it may be the result of a wider structural problem that might need investigating. When it comes to repairs, it will depend on the size of the crack. ‘Decorators can normally deal with small cracks when redecorating,’ explains Carol. ‘If the cracks are deeper, you may need to call a specialist fibrous plasterer or company.’
Julie Haddow of Lime Repair suggests using a proprietary powder filler to make repairs. ‘Dry mix fillers are softer than casting plaster, which sets very hard, so it can be damaging when carving it back. Powder fillers are also softer than the wet mixed versions.’
Damage is addressed in several ways. It can sometimes be rectified on-site, or if there is a missing section, a reproduction can be made from the original. Some fibrous plaster moulding designs are available as a stock item. Where a copy is made, the process involves taking an impression or ‘squeeze’ of the existing, undamaged section and using this to create a model and then a mould in the workshop. ‘It is a more time-consuming process to work this way, but often ess
