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Coving and cornice are decorative strips covering the join between ceiling and wall. Coving is plain, cornice also has additional 3d decorative moulding. Cornice is one of the elements creating the style in many characterful historic houses.
==Types== ===Premoulded plaster=== This coving gives an excellant finish and is more damage resistant than foam. Its also non-flammable.
Its rigid, so the wall it sits on must be close to flat. Slight variations are taken up with a mix of
- slight bending of the plaster coving
- cutting the coving to enable it to lay against the wall better
- [[Filler|filling]] the wall to coving gap
The coving is stuck in place with high grab [[adhesive]]. Once set, the cracks & gaps are [[Filler|filled]].
===Foam coving=== Polystyrene foam coving is easy to work with. But its not as robust, and its tendency to follow wall variations can look poor on occasion.
===Run in situ=== Cornice run in situ is more work than the premoulded types. Its good
- on walls that are smooth but not flat
- to replace a missing section of an existing extrudable moulding
It can create more or less any extrudable profile.
# Cut the required profile into a piece of wood # Mix plaster # Apply a layer of plaster to the wall and profile it with the wooden tool # Later apply another layer and profile it, repeating to build up the full depth
===Moulded on site=== Cornice can be moulded on site when needed to replace a missing section of cornice with a non-extrudable shape. Its a labour intensive process. # A section of the existing cornice is coated with mould release (eg diesel) # a moulding material is applied, such as silicone sealant # slightly flexible reinforcement is applied to the back of it, such as scrim & thin wood strips # When set its removed and used to mould new sections of cornice, always using a mould release agent. # The new cornice is made from alternating layers of plaster and hessian or scrim. The hessian reinforces the plaster.
Such mouldings can be heavy, and are likely to need [[Adhesive| gluing]] & [[screw]]ing in place.
===Wood=== Some decorative cornice profiles can be made by putting together wood mouldings. Material cost is higher, but labour far less than moulding plaster cornice.
==Adding 3d decoration== Plain coving or extrusion shaped decorative cornice can be made more decorative by adding non-extruded shapes such as egg & dart. The add- on shapes are simply stuck onto the cornice, taking care to get spacing and alignment correct. Once [[paint]]ed they look like part of the moulding.
==Paint== Layers of [[paint]] build up and obscure detail over time, turning a crisp clean profile into something not looking as good. This can be avoided by painting cornice with [[Paint|distemper]]. Distemper looks like emulsion but can be washed off with [[Domestic Hot Water|hot water]] to avoid buildup.
[[Category:Decorating]] [[Category:Period Property]] [[Category:Plastering]]