In last month’s article, we looked at dry rot – potentially the most damaging timber defect plaguing British homes. It is not the only serious timber defect that we, as surveyors, come across though, nor is it the most common.
In fact, wet rot is found considerably more often and, whilst easier to treat than its drier counterpart, can still be a significant cause of structural issues.
Wet rot fungi can be broken down into two variants: brown and white. In general the key difference is in their effect on the wood – with brown rot causing cuboidal cracking and shrinkage of the timber, whilst white rot reduces the timber to a stringy, fibrous texture.
Identifying brown rot
The most common form of wet rot found domestically is Coniophora Puteana, known as Cellar Fungus . Identifying characteristics:
- a dark brown-black, sheet-like growth with delicate brown threads sprouting from the rotting wood
- The fruiting body is rare, but when present will be brown, with a slightly lumpy texture and cream coloured margins.
Identifying white rot
Most commonly, white rot found domestically is known as Phellinus Contiguus. Identifying characteristics:
- The vegetative part of the fungus (or mycelium), forms as a light brown, sheet-like growth.
- Bunches of light brown threads might be seen sprouting from the rotting wood.
- The fruiting body of P.Contiguus is brown, with lots of small pores and it has a woody nature, it often hugs the contours of the host timber and may have a slightly corrugated appearance. The mycelium may also attack external masonry.
For both forms of rot, significant damage can be caused to the structural performance of the building material as the fungus feeds upon the cellulose and lignin in the wood.
As with dry rot, identifying the cause of the dampness is crucial. It could be something as simple as a plumbing leak, or something more integral like rising damp.
Inspection by a surveyor is highly recommended. A competent RICS professional will be able to analyse the defect, identify the cause and recommend suitable, cost-effective solutions.
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 sterilising to prevent any reccurrence.