Decorative plasterwork is an architectural feature that dates back to the days of the Roman Empire, and various techniques and styles have come in and out of fashion over the centuries.
Although the feature is often associated with stately homes, palaces, and grand old public buildings such as banks, theatres and town halls, some beautiful smaller scale examples of ceiling roses and coving can be found in period UK homes, especially those dating from the Victorian and Edwardian era.
If you are involved in a restoration project or interested in commissioning decorative plasterwork for a building, here is some useful background information.
What materials are used for decorative plasterwork?
A range of materials can be used, including stucco, lime plaster, and clay plaster. If you want to restore plasterwork features in a listed building, you may be advised to use fibrous plaster. This is composed of plaster of Paris and layers of hessian fabric, and was used extensively in the late 19th century for ceiling roses and cornices.
Fibrous plaster could be used to mass-produce smaller intricate items and for precast elements such as panels and niches. Compared with other materials, fibrous plaster is excellent for forming detailed ornate shapes, and is light and quick to work with.
This made it a very popular material, reaching its peak during the late 19th century when it was used extensively to decorate the numerous theatres and music halls that were built during this era. Prominent examples can still be found today in public buildings such as the Royal Opera House and St James’ Hall in London.
During the postwar era in Britain, the use of fibrous plaster declined as newer techniques and materials such as gypsum came into wider use. The restoration of fibrous plasterwork in historical buildings is now a highly specialised skill and should only be attempted by suitably qualified professionals.
Plasterwork in older buildings is particularly susceptible to water damage from rising damp, leaks, erosion, or general neglect. Moisture can cause the plaster to soften and break apart, and much of the fine ornate detail is lost.
Therefore the restoration of plasterwork should be carried out alongside other repairs or restoration work to ensure that the building is watertight and damp proof.
How are decorative plaster features made?
Traditionally, ornate decorative plasterwork has been produced by making a full-scale model of the decorative feature and then producing a mould. Historically, these moulds were made from gelatine and animal glue, but nowadays modern materials such as silicone or fibreglass are usually used.
For a larger and more intricate piece, several moulds may be made separately to form the whole to make the project manageable. The plasterwork is then built up in layers inside the mould.
Once the plaster has set, it is carefully removed from the mould and stored in optimum conditions to allow it to dry out without becoming damp. The piece or multiple pieces will then be delivered for expert installation on site.
