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Property Surveying Blog
January 12, 2017

Wet Rot, Know the Facts

Written by Richard Palmer

As Party Wall Surveyors we are often asked a variety of surveying questions, this week we were asked about Wet Rot and we thought it would be a good subject to write a short blog post on.

Wet Rot commonly refers to a family of fungi that affect timbers inside and outside the home; for the purpose of this blog we will focus on one of the most common within the United Kingdom namely ‘Cellar Fungus or Cellar Rot.’

Visually you may notice what is known as ‘cuboidal cracking’ in areas affected by Dry Rot. In layman terms this means the timber will crack longways along the grain, in a square or cube like fashion, there will also be more minor cracks across the grain.

Wet RotIt is also common to see a severe darkening of the wood as well as the wood turning to stringy, fibrous pieces, accompanying a wet and musty smell.

This type of rot can be harder to identify as it shares many characteristics with Dry Rot. The best way of identification is by the characteristics of its ‘hyphae’ or roots, which are yellowish to dark brown in colour and extend singularly from the original spore.

As the name suggests, this family of fungi tends to thrive in conditions that are very wet, nearly saturated, and are caused in much the same way as any fungal infestation with a fungal spore landing on a sufficiently damp timber for the infestation to start.

Wet Rot has been found to be present in timber with moisture content more than 60% saturation and is not found in timbers below 43% moisture content, as it ceases to be able to survive.

Generally speaking, it is often found away from a light source, hence the term Cellar Fungus, as most underground rooms tend to be less brightly lit than their upstairs counterparts and lack direct sunlight through windows.

Wet rot is known to survive in a large range of temperatures from -30 to +40 degrees Centigrade, although the fastest rate of growth is at 23 degrees Centigrade.

Before we look at how to get rid of the fungus, we must get to the root of the issue. If the problem or problems are causing the correct growth conditions, the fungus will return or continue with its growth.

For Wet Rot, dampness and reoccurring moisture are the roots of the problem.

The cause needs to be identified and problems such as a cracked pipe, damp or water ingress from defective pointing or even a combination of the two need to be considered and investigated.Screen Shot 2017-01-12 at 11.27.34

Once the source of the damp has been established and dealt with appropriately, in time the Wet Rot will die off rapidly with a complete die off of the fungus recorded at 94 days, once the moisture level in the timber has reduced to under 50%.

As the growth of the fungus will have affected the strength of the affected timber parts, it is important to isolate the parts of the building affected by the attack.

Once identified, all affected timber should be removed and reinstated with new treated timbers, this will remove the fruiting bodies and roots of the fungus and make sure that the new parts are structurally sound.

If you have a question, you would like our team of experienced Chartered Surveyors to answer, give us a call now and we will be happy to assist.