Preserving wood – Wood has to be preserved in order to protect it from rot. If a wooden item isn’t treated in some way, it will be attacked by bacteria, fungus or insects and begin to decay. How quickly this happens depends on the type of wood and the environment it is used in. For example timber items that are continuously wet or exposed to damp conditions – such as fence posts – will rot more quickly than items that are normally dry. But whether it’s a fence, a deck or an entire timber building, if it’s not protected against rot it will eventually become too weak to do it’s job properly and break or collapse.