Dry rot

It was previously used to describe any decay of cured wood in ships and buildings by a fungus which resulted in a darkly colored deteriorated and cracked condition.

Both species of fungi cause brown rot decay, preferentially removing cellulose and hemicellulose from the timber, leaving a brittle matrix of modified lignin.

The term dry rot is somewhat misleading, as both species of fungi Serpula lacrymans and Meruliporia incrassata require an elevated moisture content to initiate an attack on timber (28–30%).

Water translocated in this fashion carries nutrients to the extremities of the organism; not, as is sometimes inferred, to simply render dry timber wet enough to attack.

The term was used because the damage was present in cured or dried timber of ships and buildings and was thought to be caused by internal ‘fermentations’ rather than water.

32, Walbrook, London continues to use, manufacture and sell paints prepared with the Oil of Coal, which is of a very penetrating nature, and hardens wood in an uncommon degree protecting it from weather, dry rot and ice".

Thomas Wade's 'A Treatise on the Dry Rot in Timber' was published posthumously by the Navy Office in 1815 following his investigation of the matter in ships from various countries.

[13] Texts published in the 19th and early 20th centuries also used the term to describe fungi which produced substantial (white-colored) mycelium, including Antrodia (Fibroporia) vaillantii.

Eventually, the term dry rot came to apply to only one or two fungi[citation needed] the main one being Serpula lacrymans, in the majority of texts dealing with the subject, predominantly from the United Kingdom.

In some cases after this is done, decayed areas can be treated with special epoxy formulations that fill-in the channels of the damaged wood, killing the rot and improving structural integrity.

However, this type of treatment can actually promote decay[16] in wood in exterior service unless the epoxy application is designed to shed water.

In certain buildings, particularly those with solid 9 inch (or greater) brickwork and those built using lime mortar and flintstone, dry rot has been known to travel through and along the wall surface behind plaster and render.

It is therefore recommended, by companies that sell this service, that where dry rot is found, plaster and wall coverings should be stripped back to a metre past the infestation in all directions and the whole area treated.