Advice & Guidance
Throughout history, timber has been used as a structural material in walls, floors and roofs and can last indefinitely if properly maintained. Any problems are usually attributable to dampness, which can lead to fungal infestation and wood-boring insect damage.
Oak, chestnut and certain other hardwoods are generally very durable and grow harder with age. They also have a natural resistance to decay and insect attack. On the other hand, softwoods, such as pine and fir, are generally less durable and need to be painted to protect them from decay.
The most vulnerable part of all timber is the outer sapwood. If you suspect that there is timber decay or possible insect infestation in your building, seek advice from your architect or surveyor, rather than someone with a vested interest in a method of treatment. It is usually possible to treat such problems sympathetically. Wholesale timber treatment with chemical preparations is rarely necessary but independent advice from a timber specialist (rather than a treatment company) may be required. Also, remember to ask your cleaning team if they have swept up any insect debris. Evidence of insect attack is often cleaned away and not reported.
Joints, particularly between structural sections or between the timber component and adjacent masonry, can also be problematic. If water is able to penetrate these areas, it can do serious damage, so it is important to check any timberwork carefully in order to spot potential problems at an early stage. A skilled carpenter or joiner will be able to cut out small areas of decay and repair them with a new piece of timber. The distortion of timbers is rarely a problem and is usually attributable to the natural movement that occurred while the timber was drying out.
Action point: If areas of softwood have previously been painted, make sure that the integrity of the surface is maintained. This will probably mean repainting external timberwork every few years. If the surface is allowed to break down, water can penetrate the cracks and become trapped leading to decay. If your building is Grade I or Grade II* listed you should consider using traditional lead paint as this has a pleasing appearance and is long lasting. If you are not able to use lead paint, you might consider using other types of traditional linseed oil paint instead.
- SPAB Technical Q&A 26: Timber Decaying Fungi
- SPAB Technical Q&A 28: Wood-boring Insects
- SPAB National Maintenance Week: Getting to Grips with Damp
© SPAB 2012