What are decorative mouldings?

Art forms in their own right, timber and plaster mouldings are an important architectural device that help provide proportion to interiors while indicating the status of the building and of individual rooms. As ornamental elements, mouldings were designed to impress visitors, so the most highly embellished examples were reserved for hallways and reception rooms, with simpler styles used in more workaday areas.

Some mouldings originate from necessity: cornices and architraves cover unsightly joints between different building elements, while picture rails save the need for hooks to be driven into walls, dado rails prevent chairs scuffing wall coverings, skirting boards protect the base of walls and corbels act as supporting brackets.

Are they made from different materials?

Many mouldings were made up of a number of sections, either formed in situ or applied separately. Sometimes the final element was a composite of materials, so what looks like wood may be plaster or even papier mâché.

  • Timber Early mouldings were fashioned by hand using a range of moulding planes, but machinery revolutionised manufacture in mid-Victorian times, resulting in shapes being simplified.
  • Plaster Cornices and other profiles were run in situ using a ‘running mould’. To enhance the overall effect, separate, individually cast plaster mouldings or enrichments were applied.
  • Fibrous plaster Much lighter and stronger than solid plaster, fibrous plasterwork consists of plaster, hessian and timber laths, making it possible to cast complete lengths of cornice and other items in one prefabricated piece.
  • Papier mâché Used as a substitute for plaster mouldings in the 18th and 19th centuries, papier mâché is principally formed of layered or pulped paper that is pressed into a mould and bound with glue, sometimes with gypsum or other suitable fillers added.
Decorative ceiling rose

Highly embellished ceiling roses are a key decorative feature in period homes

Do your research

Not all rooms in a house had mouldings, so adding inappropriate ceiling roses and cornices can ruin the proportions and relevance of a space. Detective work will sometimes reveal evidence of where mouldings once were. When wallpaper is stripped, parallel lines of paint on the plaster and patched nail holes may show the position of long lost dado and picture rails.

A visit to neighbouring houses that have not undergone extensive renovation may also provide a good guide to the type and style of mouldings originally used.

How can I spot damaged mouldings?

Mouldings are easily damaged by everyday wear and tear and are often a casualty of renovation work. Water penetration from leaking roofs frequently harms plaster cornices, while damp will result in rot and insect attack that may affect skirting boards and other joinery mouldings.

What to look for

  • Missing sections
  • Detail obscured by paint layers
  • Chips, splits and other damage
  • Loose items
  • Damp, rot and insect infestation
Repairing original mouldings

To avoid damaging mouldings, it’s important to protect them during any building work

Making repairs to plasterwork

Wherever possible, original mouldings should be retained and repaired. Care should be taken not to dislodge sections, and fragile detailing should be supported and protected during building work.

  • Fill small cracks with proprietary filler.
  • Use plaster of Paris to fill larger cracks and to remake small areas.
  • With common designs, use off-the-peg fibrous plaster components to infill missing sections.
  • Have broken or missing details remade using casts of existing items.
  • Employ a skilled plasterer to run in new sections of cornice or make repairs.

Can I remove layers of old paint myself?

The intricate detailing of many plaster and timber mouldings is lost because it has become clogged with paint layers. Removing paint from mouldings is harder than from flat surfaces, so care must be taken to avoid damage.

  • Test your chosen removal method on a small, unobtrusive area.
  • Avoid abrasives such as wire brushes or sanders, and be careful not to dig with scrapers.
  • Warm water, steam and proprietary wallpaper stripper can be successful in removing paint from plaster.
  • Chemical removers and peel-off poultice systems may be suitable for plaster and wood.
  • Carefully use hot air guns to remove any paint from wood, but do bear in mind that scorching is a danger.
  • A toothpick and toothbrush will aid paint removal from fine detail.
Decorative plaster moulding

Removing layers of old paint from mouldings will help to reveal any intricate detailing

What’s the best way to repaint mouldings?

The majority of timber mouldings were manufactured from inexpensive softwoods, which were never left in their natural state but were instead painted in matt or semi-gloss finishes; high-gloss was never used. Expensive hardwoods such as mahogany and oak were left bare and polished to enhance the grain.

  • Remove excessive layers of old paint.
  • Lightly sand but avoid rounding crisp edges or blurring details.
  • Brush or vacuum away dust.
  • Apply paint in thin coats.

Is it possible to remove mouldings without causing damage?

Never remove mouldings unless absolutely necessary as they easily split, and remember that what looks like wood may be plaster or papier mâché. Timber mouldings were originally fixed with nails, driven either directly into the masonry or into wooden plugs or ‘grounds’ (battens) fixed to the wall first.

  • Gently tap an old chisel under timber mouldings to loosen them.
  • Use a block of wood under the chisel to provide leverage to prise the moulding away.
  • Remove nails with pliers, taking care not to damage the moulding’s front face.
  • Mouldings are best replaced using screws and wall plugs.
Ornate ceiling rose

Find original mouldings at salvage yards or look out for good examples of reproduction designs at DIY stores

Can I match new mouldings to original designs?

A huge number of moulding profiles exist and often the differences are incredibly subtle.

  • Source new sections from timber yards and good DIY stores.
  • Alternatively, some architectural salvage yards stock a range of mouldings.
  • Take a section of the original when searching for replacement mouldings.
  • Where necessary, consider having matching sections machined at a good timber yard or joinery workshop.
  • Make sure you order sufficient quantities – having mouldings specially cut can be expensive, particularly for short runs.

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