Timber decay generally arises as a result of some form of dampness, and is potentially the most destructive agent within any building. Decay by WET ROT FUNGI such as Coniophora puteana, tends to remain localised to the source of dampness and is restricted to the wood itself. If left unchecked it frequently causes joist ends and other bearing timbers to collapse, for example, where the joist ends are embedded into damp masonry.
However, infection by the true DRY ROT FUNGUS (Serpula lacrymans) can be far more destructive within a building than any of the wet rots, due to its ability to grow through and across inert materials such as brickwork and plaster. This in turn allows the fungus to contaminate other timbers within the building, spreading the extent of destruction and decay. Unfortunately, “DRY ROT is rather secretive in its movements, preferring stagnant humid conditions. Hence, when it is discovered it has frequently caused extensive damage.