By far the worst fungi we deal with is true Dry Rot. The spores are everywhere in the atmosphere, and if the condition of the timber becomes suitable, is it likely that the spores will germinate and result in an outbreak of decay.
The main requirement is that the timber moisture content is in excess of 20%. This is not a very high level in view of “dry air” timber having a moisture content of between 12 – 16%. Certain timbers are resistant to fungial attack, even when very damp, but these are not generally used in house construction. A large fruiting body of the fungus can produce 800 – 900million spores per hour. In ideal conditions its growth is very rapid, and will soon cause the timber to become cracked both with and across the grain.
It is this (Dry Rot) which has a preference for dark conditions, inadequately ventilated places, and often remains undetected until severe damage has been caused. Often the first knowledge the householder has of its presence is the cracking and/or buckling of skirting boards or rust brown spore dust. It is capable of spreading behind plaster, through mortar joints, and even across metal to find more timber or moisture to feed on. i.e. a non nutrient medium.
Wet Rot (Coniophora puteana)
The name “Wet Rot” is used to describe all other types of wood rotting fungi, of which their are numerous species, including the most common coniophora puteana & coniophora cerebella (Cellar Fungus), fiboporia vaillantii etc.
These fungi all require that the timber becomes damp and do not have the ability to “colonise” surrounding dry timbers, as in the case of “Dry Rot”.