Timber wall panelling
This article explains how to deal with timber panelling: from fungal decay to warping, and more.
How has timber panelling evolved?
Timber wall panelling originally functioned to improve the thermal insulation of walls but developed to also serve a decorative purpose. Plain vertically-boarded panelling was in use by the 13th century. More familiar framed panelling dates from the 14th century and before the 18th century was mainly of oak. Panels carved to resemble folded linen (‘linenfold’) were fashionable from the late 15th century and small square panels the following century. By Georgian times, panels had become larger, showed a classical influence and were of painted imported softwood. Wherever possible, old panelling should be retained in place.
How do I treat panelling weakened by fungal decay?
Where fungal decay has weakened timber panelling, especially that of historic value, it is preferably repaired by adding reinforcement behind. This can involve attaching timber bridging pieces to the panels and/or frame using glue or stainless steel screws but allowing the host material to move independently with changes in humidity. The panelling might also be rehung on new metal bracketing or framing to assist future removal. Where reinforcement is unviable, decay may be repaired by inserting well-seasoned matching new timber. The use of resins and consolidants, another option, should only be employed with great care. Before undertaking any repairs, it is important to deal first with the cause of decay. Fibre optic surveying techniques can assist with the inspection of voids behind panelling.
How can you repair a split timber panel?
Panels often split when they shrink but are prevented from moving within their framework, frequently due to paint accumulation. If freed, panels may be glued back together. Sometimes a timber spline is glued into the split (which may need widening) and planed flush with the panel face. The panel is held until the glue sets with temporary attachments clamped either side of the split or using suitable tape. Another option when dealing with painted panelling, and adopted at the SPAB’s headquarters, is to cover splits with a fabric-based intumescent tape. Minor splits in panels might be filled with hard, coloured wax.
How do you deal with warped panelling?
Panelling can warp when it has become damp or saturated and then undergoes rapid and uncontrolled drying. Introduce heat gradually to panelled rooms, therefore, and aim to maintain even temperatures that minimise fluctuations in humidity and the consequent expansion and contraction of timber. It may be possible to counteract warping using temporary timber blocks screw-fixed to push the panelling back into line. Sometimes panelling can be laid flat and straightened by applying an even load for several days or weeks. Another method is to remove the panelling and straighten it using a wire-and-turnbuckle arrangement.
How do I minimise damage when removing panelling?
Only remove panelling if there is little alternative, for example, to allow controlled drying out where saturated by flooding of firefighting. Components should be numbered and identified on a drawing or photograph before work begins. Dismantling will necessitate carefully locating and removing fixings. Mouldings attached to the panelling, such as dado rails, will often need to be removed first. In many cases, it is better to cut into the framework to extract a panel than to undertake major dismantling of panelling.
What should I use to paint or finish timber panelling?
Historically, oak and other fine hardwood panelling was generally waxed or resin-varnished. Softwood – widely used from the 18th century but employed for panelling as early as the 13th – was normally painted, an exception being where it was ‘grained’ to imitate hardwood. It is normally inappropriate to strip paint from softwood panelling and can be damaging. When repainting, a semi-gloss finish is frequently desirable. Early painted panelling, though, could require specialist attention from a paint conservator. Polished surfaces may be rewaxed. Wax can also be used over resin varnish (which is tricky for non-specialists to reapply). Be aware that modern varnishes may look out of place.
English Heritage (2012) Timber, Practical Building Conservation, Farnham: Ashgate Publishing Ltd
Ridout, B (2015) Timber Decay in Buildings and its Treatment, Broome: Scientific and Educational Services Ltd