Timber was often used in historical buildings, many of which are now centuries old. There are numerous examples of applications where wood has been used, even in places where it’s received a great deal of exposure, and it has still survived in good condition. However, wood does have some enemies.
- Fungal decay
- Marine bore
Luckily, there are ways these can be prevented.
Timber preservation methods
These are some of the ways timber can be successfully preserved:
- Keep timber dry. Fungal attack, rot and decay only occur when there is moisture and oxygen. Keeping timber dry avoids this type of damage. Indoors, the moisture content of the atmosphere will be less than 20%, which means that decay will not occur. When wood is dried from its original green state, it will adapt to the moisture content of the atmosphere. When the atmosphere is damper than the timber it will generally swell and, when dryer, it will tend to shrink, depending on the stability of the chosen species.
- Use wood preservatives. Wood which is exposed to damp and rain can be given extra protection with wood preservatives, water repellent preservative systems, or a protective film of paint or varnish. These need to be applied and maintained to ensure that all surfaces are completely sealed, aiming to avoid the trapping of excessive water below them. Timber used in architectural joinery is kiln dried to reduce the moisture content prior to the application of finishes.
- Choose a durable timber. Some of the more durable timbers, like oak, can be left untreated. Bear in mind that exposure to sunlight and various weather conditions will gradually fade the original colour, leaving timber silver grey.