Causes of Damage and some pointers on how to avoid it.
28 September 2005

The causes of damage to furniture can be broadly split into three main categories namely, Environmental, biological and human. Below is a brief description of each and some pointers on how to avoid them.

Environmental Damage. Changes in humidity can be very damaging to furniture. A damp environment will cause the fibres of wood to swell and if the environment is too dry they will contract. This in turn can cause wooden furniture to warp or split. An ideal environment is one with a stable relative humidity between 40% and 60%. Around 50% - 55% is ideal. With the advent of central heating many houses are very dry, especially in winter. RH can fall to 30%. If you own good quality furniture that is showing signs if shrinkage it may be a sensible idea to purchase a humidifier. Try to keep the central heating on a low setting and keep individual items of furniture away from radiators. It is the stability of the environment that is important, so unless you have cracks appearing or panels warping things are best left as they are. It is always wise to seek advice before embarking on a strategy of humidity control.

Ultra violet light, present in daylight, will bleach timber and cause polish and varnishes to discolour. This can completely obscure the wood underneath and is the cause of much re-polishing work. Heat produced by direct sunlight can also dry out glues thus loosening veneers and mouldings. I have seen polish actually melted by sunlight through a car window. It is a sensible precaution to keep items out of direct sunlight; the use of blinds or curtains during the day can help. It is also possible to purchase UV filters for windows.

It is possible for furniture varnishes to absorb dust over a period of time. Dust can also accelerate the deterioration of metals, particularly in damp environments. Regular dusting is essential. A soft cloth should be used for this with care being taken of any loose pieces that may exist.

Biological Damage. The common furniture beetle (Anobium punctatum) is the most common form of pest that causes deterioration to furniture. The adults lay eggs in wood and when the larvae mature they burrow their way to the surface, and fly away to lay more eggs. Signs of infestation are little round holes, and a fine light coloured dust accumulating underneath an item. The dust can often be the first sign, as the holes may appear on surfaces not readily visible without close inspection. Action should be taken at the first sign of infestation. There are various methods of treatment ranging from the application of liquid insecticide to a "gas chamber" for more delicate objects.

Exposure to prolonged dampness may promote the growth of fungus, which can cause staining and also weaken adhesives. A milder form is often seen as a whitish growth, especially on unpolished timber, which can be wiped away with a cloth. If this is occurring the environment is too damp. Care should be taken when moving furniture from a damp environment to a dry one- see above.

Human Damage. Furniture is easily damaged when moving it. The first thing to do before moving anything is to examine the piece for damage such as loose tops, rails, veneers or mouldings, which may become detached with handling. Remove any moving parts such as drawers and shelves. Doors should be tied shut. Furniture should never be dragged as this places huge pressures on its feet and carcass. Always lift from the strongest point, the rails of a chair - not the arms, or the frieze of a table - not the top. Chests and cabinets should be lifted from the bottom. Should loose pieces become detached save them with the piece of furniture in a plastic bag, this will save you money when you have the piece restored.

Surface damage may occur through spillages of all sorts. Any liquid containing alcohol may soften a polished surface and should be dabbed off quickly to prevent the surface marking. Water based spillages should be wiped up immediately and the surface dried with a soft, dry cloth. Take care with plants as many pots are porous, it doesn't take long for a damp pot to ruin a tabletop. If you do mark a surface, damage such as water marks can often be more easily treated straight after occurrence. Dents and bruises may occur throughout the life of a piece of furniture, they are very difficult, if not impossible, to remove without losing the original surface. Care should be taken when placing heavy objects on delicate surfaces. Care should also be taken when writing as the pressure from the point of a pen can easily bruise a table top, make sure there is sufficient padding under your piece of paper.