Wet rot is the most commonly found type of rot in the home. Whilst easier to treat than its drier counterpart, it can still be a significant cause of structural damage.
There are two main types of wet rot fungi: brown and white. In general, the key difference is the effect each type has on wood. Brown rot causes cuboidal cracking and shrinkage of the timber, caused by the removal of moisture from the wood. White rot reduces the timber to a stringy, fibrous texture.
Wet rot can occur anywhere where water has been in long-term contact with the wood. Most often the cause of wet rot within the home are:
- Broken or leaking water pipes;
- A leaking roof, damaged guttering, or defective air bricks;
- Defective seals on baths and showers; and/or
- Badly plumbed dishwashers, washing machines, or other appliances.
How to identify brown rot
The most common form of wet rot found domestically is Coniophora Puteana, a brown rot often known as Cellar Fungus. Despite its name, it can be found anywhere in a building and usually around places with active water ingress into the property, such as breaks in walls, cracked pipes or areas with high condensation and/or poor ventilation.
Its characteristics include a dark brown/black, sheet-like growth with delicate brown threads sprouting from the rotting wood, and mycelium is not always present.
The fruiting body is rare but when present it will be brown, with a slightly lumpy texture and cream coloured margins. A telltale sign that there is a fruiting body is the presence of red, rust like spore dust.
How to identify white rot
The most likely form of white rot found domestically is Phellinus Contiguus. As the term white rot implies, its characteristics include bleached timbers and eventually a stringy fibrous appearance. Mycelium may also form appearing as a light brown, sheet-like growth. Bunches of light brown threads might be seen sprouting from the rotting wood.
The fruiting body is brown, with lots of small pores. It has a woody nature, often found hugging the contours of the host timber and may have a slightly corrugated appearance. The mycelium may also attack the building externally.
The damage
Both brown and white forms of rot can cause significant damage to the structural performance of the building material as the fungus feeds upon the cellulose and lignin in the wood. However, unlike dry rot, wet rot does not spread to other timbers and it will stop growing once the source of moisture has been removed and the timbers have dried out. It also cannot live within masonry.
The solution
As with dry rot, identifying the source of the dampness is crucial. It could be something as simple as a plumbing leak, or something more integral like rising damp.
Once the source of the dampness has been addressed, the affected wood should be removed and replaced with pre-treated timbers. Any retained timbers will likely need irrigation and sterilisation to prevent any recurrence of the problem.
Inspection by an independent Chartered Surveyor is highly recommended. The surveyor will analyse the defect, identify the cause and recommend suitable, cost-effective solutions.