Wet Rot

Wet rot is a type of fungi that attacks timber in order to feed on it, destroying the cellulose and lignin of the wood in the process. If left unchecked, it can severely weaken the structural integrity of the timber. As a result, full replacement timber may be required.

Both old and new buildings are vulnerable to wood rot. Wet rot in Sheffield buildings thrives in damp, moist environments, particularly in areas where there is poor ventilation. The rot appears as a fleshy ‘fruiting body,’ made up of vegetative fibrous mycelium.

The many symptoms of wet rot in wood include shrinkage, cracking and a brittle appearance. All of these symptoms can also indicate dry rot. Therefore, it is essential to be able to identify the differences between the two.

Spores of wet rot germinate in the pores of the timber, resulting in vegetation that feeds on the timber and spreads to produce a fruiting body. This fruiting body will release more spores and the cycle will continue!

The Cause:

High moisture content in wood allows the fungus to establish. Common causes of moisture in the woodwork of properties are due to gutter leaks, plumbing leaks and roofing defects. Poorly ventilated environments are also a typical cause.

Wet rot is a group of many species of wood rots. These can be subdivided into brown and white rots, which have different effects on the wood dependent on what type of rot is present.

Brown Rot:

  • Brown rot presents itself as cuboidal cracking and timber shrinkage.
  • The most common type of brown rot found is ‘Cellar Fungus’ (Coniophora Puteana).
  • The vegetative part (mycelium) of Cellar Fungus presents itself as a dark brown, sheet-like growth with delicate brown threads sprouting from the rotting wood.
  • White sheets of mycelium can sometimes be seen in early stages of development.
  • The fruiting body is brown with a slightly lumpy texture and cream coloured margins. However, this is rarely seen.
  • Another common brown rot fungus found is ‘Mine Fungus’ (Fibroporia Vaillini).

White Rot:

  • White rot presents itself in a stringy, fibrous texture.
  • The most common type of white rot found is Phellinus Contiguus – which has no common name!
  • The vegetative part of the fungus presents itself as a light brown, sheet-like growth
  • Bunches of light brown threads may sprout from rotting wood.
  • The fruiting body is brown, has lots of small pores and a woody nature. It can have a corrugated appearance and ‘hugs’ the affected timber.
  • The other most frequently found white wet rot is Oyster Fungus (Pleurotus Ostreatus, Donkioporia Expansa).
  • The other most frequently found white wet rots are Pleurotus Ostreatus (Oyster Fungus) and Donkioporia Expansa which has no common name.