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Care and conservation of furniture

Most pieces of furniture are complex structures, sometimes made with several different types of materials on the same piece, for example: wood (a spectrum of species), metals, textiles and upholstery, leather, glass, ceramic, tortoiseshell, ivory, paint, varnishes and metal leaf. All of these are at risk from deterioration of some type, but each has an environmental ‘ideal’ which can maximise its preservation. Compromise is inevitable but, with care, the need for treatment should be infrequent. When undertaking treatment, conservators adopt an approach of 'minimum intervention' and will look for a balance between function, aesthetics and the preservation of the historic finishes and surfaces which have the potential to reveal much about the history of a piece.

Potential causes of damage
Temperature and relative humidity
Organic materials such as wood are hygroscopic and will react to changes in the moisture content of the air around them. Very low relative humidity (dry air) will cause drying out and shrinkage of most timbers; and damage can sometimes result depending on the construction and complexity of the piece. Conversely, a damp environment may result in expansion of the wood. A fluctuating environment has the greatest potential to cause damage as the repeated expansion and contraction of the wood causes stress within the furniture. Cracks and splits in furniture or lifting veneers may be a sign of an unstable environment.

A conservator can provide advice on the most suitable environment for a particular object based on an understanding of the materials used in its construction.

Light
Light and ultra-violet radiation (present in daylight) can cause colour changes to timbers and pigments, and the eventual disintegration of textiles. Light damage is cumulative and irreversible (i.e. it gets worse over time). Comparison of a surface exposed to light with one that is protected (for example a drawer or underside of a piece of furniture) may indicate whether light damage has occurred.

Insects and pests
Pests are another cause of damage. Some timbers (e.g. softwoods, beech, walnut, lime, oak, ash) can be at risk from attack by woodboring insects, especially in damp conditions (above 70% relative humidity), which encourage insect activity and mould/fungal attack. Signs of pest damage include fresh exit holes and the presence of insect residue (which often looks like sawdust), known as frass.

Handling
Furniture is also vulnerable to damage through use, although careful usage can be helpful in overall preservation because it means the object is not neglected.

What you can do to protect your furniture
Environment
Try to maintain a stable environment (temperature and humidity) and avoid placing furniture near sources of heat such as radiators as the surrounding air will be very dry. Similarly, try to avoid placing valuable furniture in direct sunlight, use blinds to reduce the amount of daylight or use UV filters on windows.

Check your furniture regularly for signs of damage. Avoid scratches from things like ornaments, clocks and vases by protecting the surface - for example by using coasters or glass table tops (placing small pieces of felt between the glass and table top will stop the glass sticking) and pay particular care to protecting from damage by water and other liquids which can badly affect historic surfaces, especially gilding.

An annual inspection in late spring for signs of insect activity such as exit holes is always a good idea.

• If evidence of fresh pest activity is found, wrap the furniture in plastic and try to move it away from other items. Consult a conservator or pest expert as soon as possible.

Cleaning
Clean simple polished surfaces and brass fittings by giving them a light dusting with a clean, dry duster (not a feather duster – which can cause scratches); be careful around areas of loss as the surrounding pieces are often loose and easily knocked off.

Complex surfaces (marquetry, inlay, boulle, lacquer, painted surfaces and carving) frequently have uneven surfaces; even a slight projection is enough to snag a duster and leave unsightly fibres, or worse, damage from pieces being detached completely. These surfaces should be cleaned using a soft banister brush, or for small areas a pony hair brush. Gilded surfaces which are sound should be cleaned with a soft pony hair brush only, be sure to assess the condition before embarking on cleaning.

Metal cleaning products can damage a surrounding wood finish so it is best just to give metal hardware a buff with a clean, dry cloth.

Polishing should be infrequent; only when needed to buff out marks in wax polish. Use a good furniture wax (with beeswax); apply sparingly with a clean duster and buff with another. Wood does not need 'feeding' and the only effective way to stop drying out is to maintain a suitable, stable environment (relative humidity of 40-60%). Avoid the use of spray polishes or those containing silicon as these can damage historic finishes and leave residues. Remember that 'French polish' is a special finish to furniture and that it is not the same thing as a wax furniture polish. French polishing should only be carried out by specialists.

Moving and handling furniture
Take care when moving and handling antique furniture. Always plan your route; check that there are no obstructions and that the piece will fit comfortably through doorways and other restricted spaces. The following guidelines can help to prevent damage:

• Check the furniture carefully before attempting to move it. Look out for damage, loose areas and joins.
• Assess the surfaces that will be touched. Are they gilded? If so, cotton gloves are in order.
• Separate the object into smaller units; leave nothing which could become detached; lock doors and drawers if they are staying in.
• Most furniture will need a minimum of two people to move it safely. Assess the load before lifting (to protect yourself as well as the furniture).
• Always lift a piece of furniture straight up, being sure to handle it at its strongest point (for example legs rather than table tops, and seat rails rather than chair arms). Avoid tipping and dragging as this can put too much strain on legs and feet.
• Carry marble and glass tops and mirrors vertically as they can break under their own weight. To lift a marble top, first move it forward a small distance, then tip onto its back edge supporting the underside; set it down vertically on battens previously laid out near the piece’s destination.
• A carved, ornate frame may need ‘stilts’ temporarily attached to the back through its fixing points to take the weight off the wall (e.g. a one-piece plywood panel) – a conservator will able to do this for you.
• It may be necessary to use wedges to compensate for uneven floors.

Consulting a conservator
Enthusiastic amateurs can be tempted to try to restore furniture. Sadly, the effects of inappropriate treatment can be worse (and more costly) than if the piece had been left alone. The wisest course of action is to contact a professional furniture conservator. In addition to the remedial treatment of furniture, conservators can:

• provide advice on the monitoring and control of the environment. He or she can also advise if your objects need protection from light damage, for example through the use of blinds or UV filters; or can suggest methods for reducing the amount of time that the object is exposed to light.
• assess the condition of items and provide a range of treatment options together with explanations
• provide advice on storage or transport
• provide recommendations for future care

Use the Conservation Register to Find a conservator.

© Icon, the Institute of Conservation 2006.

This article offers general guidance and is not intended to be a substitute for the professional advice of an accredited conservator. The views expressed are those of the author or authors, and do not necessarily represent the views of the Institute of Conservation. The Institute of Conservation would like to acknowledge use of the MGC publication 'Ours for Keeps' in the preparation of this text. The Institute of Conservation and its partners accept no liability for any loss or damage which may arise if this guidance is followed.

The Institute of Conservation would like to acknowledge the support of The Royal Commission for the Exhibition of 1851 in the production of this guidance information. Further information on The Royal Commission for the Exhibition of 1851 and its work is available at www.royalcommission1851.org.uk.