Wet Rot

Fungal decay/rot always arises because the wood has become wet, usually timbers will be in excess of 20 per cent moisture content.


Finding the source of dampness and eliminating the ingress of moisture and promoting drying is always necessary and is the first course of action required.

Where it all starts

The Outbreak

Outbreaks of both dry rot and wet rot start in similar ways. The mature fruiting bodies of wood-destroying fungi that develop during an attack produce millions of microscopic spores and these are widely dispersed by air currents.


If they fall on untreated damp wood they will germinate by pushing out a hollow tube called a hypha which grows and branches to form a mass of hyphal threads called mycelium. Mycelium develops inside the timber and breaks down the wood for food. The timber may darken in colour and develop a characteristic cracked appearance.

How it gets established

Taking Hold

Some wet rots may result in bleaching of the wood; these are more common in doors and window frames. Eventually, the wood loses its strength and in some situations may become dangerously unsafe.


The main differences between dry rot and wet rot are the degree of development of mycelium on the wood surface and the ability of the fungus to spread into other timbers via adjacent masonry.

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Know your fungus


It is very important that the two types of decay be distinguished since they require different treatments.  If you are unsure about the type of rot at your property then please contact us on 01403 740055 or info@insituscp.co.uk


Wet rot is caused principally by Coniophora puteana.  Poria vaillantii is another important wet rot fungus and a number of less common fungi also occur. While each fungus has its own unique features, the general appearance of wet rot is similar – as is the treatment. Wet rot is typically confined to the immediate area of dampness because the mycelium does not spread into walls.

Finding the source


It is very important that the type and cause of the fungal decay is correctly identified before any corrective action can be considered.


It is for these reasons that it is important that a detailed inspection is carried out by a competent and qualified specialist. This inspection should be followed by the submission of a written report that details both the cause of the decay and the proposed remedial action.


InsituSCP can provide this service for you.

How can we help?

About Insitu SCP

Please contact us to discuss your requirements and we will do our utmost to assist you. Insitu SCP are one of the most established names in building preservation in the South East of England, with over 40 years experience in the industry. You can be assured that we will identify potential issues, find the best solution and deliver long lasting results with minimal disruption.