Living with Antique Furniture
The Natural Enemies
Until the first quarter of the 20th. century, most furniture was made with natural organic materials, whereas today some of the organic materials have been made more stable with the introduction of chipboard, hardboard and MDF. It is the instability of wood in particular that makes furniture so vulnerable to climatic change and wood is the staple diet of some insects. Attachments of leather and fabric are similarly vulnerable.
Most finishes which were traditionally applied to wood, shellac, oil, paint, varnish and lacquer, although made from natural vegetable and mineral materials, have rates of expansion which are very different from most woods. When the movement in wood is fairly small, there is no problem. If, however, the wood is subjected to large climatic changes, the finishes may lift and crack. Veneers, woods different from the substrates, damage easily and the most common fault is lifting and splitting. The beeswax finish tends to be an exception as far as wood movement is concerned but it does deteriorate under heat and fluids.
Central heating is the principal enemy of furniture. Movement in wood is caused mostly by alterations in its moisture content which in turn is largely governed by the humidity of the surrounding air. Central heating dries the air by lowering the humidity. The natural average moisture content of wood in which it is happiest is between say 10% and 12%, so the air around it should be kept at around the same humidity if we are to expect the wood to remain stable. Unfortunately many modern houses are so well insulated, draught-free and warm that the humidity may drop substantially. For the wellbeing of the custodian and the furniture, the relative humidity should be kept at 45 to 55%.A practical solution is :
- Install a humidifier. Alternatives to this, but not as good, are to put containers of water under or close to vulnerable furniture or hang containers of water with fabric wicks on the radiators.
- Monitor the room’s moisture content with a meter so that you may control the humidity.
Sunlight, magnified by the glass in your windows, has a devastating effect on wood and the surface finish. All the traditional finishes will oxidize under sunlight, they will change colour, usually by fading and some will break down and become cloudy and even opaque. Wherever practicable, furniture should be kept out of sunlight. Our forbears of 17th to 19th centuries knew this and rooms used to be shuttered or blinds fitted to protect the decor, paintings, fabrics and furniture. We seem largely to have ignored this in the 20th century.
There is here an odd anomaly: the most valuable asset of old furniture is the patina it acquires through age and use. Much of the patina is due to the effects of light, but good patina is acquired very gradually.
After man, Anobium Punctatum (common furniture beetle) is furniture’s second most common natural living enemy. The insect is in flight twice a year and lays its eggs in the cracks and crevices of furniture. The larvae hatch and eat the wood for food by boring their way finally to reach the surface and start the whole process again. Some woods are evidently tastier than others. Oak, walnut and pine are the most vulnerable. Curiously, mahogany is almost never attacked although flight holes may be found in veneers.
The wood becomes more attractive to the furniture beetle when it is damp. Consequently feet, plinths and backboards on damp or stone and tiled floors are especially vulnerable. The backboards of longcase clocks are often badly affected and the remedial action taken by unscrupulous and unknowledgeable restorers is often catastrophic. So many clocks have been shortened or had false plinths added to disguise insect or rot damage. Historically, wainscoting (wood panelling) up to the natural height (3’6” – 4’) of rising damp in walls, was fitted to mitigate the effects of no damp courses. In buildings without wainscoting and without a damp course, insect damage to the furniture inside may be expected more on the ground floor than above.
The precautions we should take against woodworm attack are :
- Regularly inspect your furniture all over for tell-tale holes and especially for the dust or ‘frass’ which comes out of them when the damage is active.
- Deal with worm attack using a proprietary wood worm fluid squirted into each and every hole. Wipe the surfaces clean afterwards.
- You may prevent or lessen the chance of attack by insects in their flight season by burning special candles and you can also put up flytraps nearby.
In advanced cases, you may have to have furniture dealt with by fumigation, either as a service or a DIY measure. A relatively new and totally ‘green’ and effective method is treatment by the Thermo Lignum Process in which the objects under treatment are heated up to a maximum of 53-55° C. at which temperatures all animal protein dies. Other bugs such as ‘woolly bear’ in textiles are effectively treated using the same methods or by freezing.
Dealers should tell you if woodworm is present but more likely they will say it is clean and/or has been treated. In the latter case you are little better off unless there is proof. What ought to happen is that every piece of furniture for sale should be professionally inspected for insect attack and a certificate of cleanliness issued.
The key to protecting furniture against attack is regular inspection.
(3)Human Attack and Mismanagement
The Physical. Overloading drawers overloads the runners and causes rapid wear. The drawer fronts will sag and eventually the runners will either wear through the face veneers of the drawer rails or ‘ping off’ the veneer by splitting it.
Letting oversized people sit in undersized chairs and, worse still, letting them tilt the chair backwards, will destroy the chair. It has been known to damage the sitter also – poetic justice. In fact tilting any chair (other than the rocker) subjects the frame to levels of stress for which is not designed.
Dragging heavy furniture across the floor, and especially a carpeted floor, will put heavy stresses on the carcase and may cause veneered feet and plinths to split and de-laminate. Heavy furniture should be lifted and not slid. Chairs should ideally always be picked up with hands each side of the seat frame, never lifted by their backs or the arms, for neither are designed to withstand the strain.
Castors have been fitted for centuries to all sorts of furniture and this makes it safe to move without lifting, providing the castors work. Check that castors are not seized and will both rotate and swivel.
Water damage from flower vases or just through natural siphonage from plants and cut flowers is the most common. Water wiped off early is unlikely to cause much damage that cannot be cured with some wax polish. If you let it stand, especially when trapped under a vase or mat, it will damage the surface finish or polish and eventually penetrate the wood and lift any veneers. The first action must be to dry the surface. If there is permanent damage do not touch but call in a BAFRA accredited restorer. Damage by wine and spirits is worse in that it happens more quickly and may stain the underlying wood irrevocably. Again dry the area and if damaged call in the expert.
Mechanical damage by scratching or impact is often less severe than the above. If a scratch is just in the surface coating, it can often effectively be treated with wax if it is not too deep or with a good quality wax polish. Avoid using proprietary scratch removers or revivers. Scratches through the polish and down to or into the wood are cases for the conservator-restorer.
Care of Furniture
Keep your furniture clean by regular dusting with a soft clean cloth, not feather dusters as they tend to catch in rough areas of veneer and inlays. Better to use a soft brush.
For dirt that is difficult to remove such as sugar, jam and fats, use a clean cotton cloth damped with a solution of vinegar (a sherry glass) in clean water (1 pint) and use it sparingly. Make sure that the cleansed surface is really well dried.
Wax that does not contain mineral waxes (which fingermark and smear) is the best regular protective treatment for furniture. Waxing on all but the hardest used furniture should be at about 6 monthly intervals and waxing must be done after cleaning/dusting. For the hard-used dining table, which presumably gets some hard cleaning as well, waxing at monthly intervals should be enough. More frequent wax polishing may render a build-up of soft wax which attracts dirt and dust and never burnishes well.
Avoid cleaning any brass fittings as they may well be gilded (ormolu) and the integrity of the piece could be damaged.
Furniture is valuable to us all both through sentiment and love of the applied and decorative arts. With sentimental and financial value it deserves the best attention and as its custodian, you do have a responsibility to pass your furniture to future generations in good order.
The British Antique Furniture Restorers’ Association (BAFRA) has over 90 accredited conservator-restorers. The logo below is usually displayed in BAFRA Members’ advertisements. You can always check validity of the logo or the restorer’s claim to BAFRA membership by ringing BAFRA’s Head Office on the numbers below, or look on our web site. The Head Office is always ready to help and BAFRA offers a number of publications and events for the public’s and its members’ use.
Telephone 01939 210826