Wood is an organic material that will, over time, rot and decompose. Some woods will tend to decompose more quickly than others. Wood rot and decay is caused by various molds and fungi that feed on the wood and some woods are more resistant to these than others.
Some woods are extremely resistant to decay. Highly resistant varieties include Yew, Red Mulberry and Black Locust. Some others which are resistant but not as highly as these include Cedar, White Oak, Redwood and Juniper. But at the lower end of the scale are woods which offer minimal natural resistance and these include Pine, Birch, Beech, Ash and Alders.
Treating wood to make is resistant to rot has been practiced every since wood was first used to construct buildings. There are records which indicate that wood used by Alexander the great to build bridges was treated with olive oil in order to extend its life. And Romans protected their ships with a coat of tar, a practice that continues to be used today.
Wood is made up of cells, much like a sponge. Wood preservation treatments are aimed at coating these cell walls to stop fungi and mold from eating them. Pressure treatment is one of the ways in which preservative is forced in the cellular structure of the wood. This is a two stage process that firstly sucks all of the air out of the wood by placing it into a vacuum before forcing preservative into the wood under pressure.
Wood preservation in and around the home involves being vigilant. You must look out for signs of rot and fungi, especially on structural timber. Sometimes this can be hard to inspect so you may need to employ a professional surveyor, once every couple of years, to carry out a detailed timber survey.
Dry rot is a particular concern for property owners. It tends to attack timber that is damp and is commonly found in the timber joists used in bathrooms or utility rooms which house washing machines. Dry rot is particularly nasty as it can travel around a home via other building materials. Dry rot can cause extensive property damage and must be treated promptly if identified.
Common indicators are wood shrinking and cracking on the surface, fluffy white mould appears, there is a musty, damp odour. But if your concern is for your domestic woodwork such as sheds, fences, outdoor furniture, doors and window frames then its generally a matter of ensuring that the wood is adequately protected from the elements. Ultraviolet light, for example, can be damaging to many woods so a protective coating that includes a UV filter is a good idea.
Its important that you use the right form of wood preservative for your wood. For example, if you have an oak gate then you should use an oak preservative and this is probably not suitable for your pine wood fencing. But there are some truly remarkable wood treatment products available today so whatever you want to protect and preserve you are certain to find a suitable wood preservative. To find the best wood preservative for your needs you should consult a professional.