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  • Alex Ainger

Wet Rot and Dry Rot– What are they and how do you spot it?

Dry Rot and Wet Rot are both conditions of timber that have been affected by wood-rotting fungi. These conditions can be found both in the interior and on the exterior of your property, depending on which conditions best suit the respective type of fungus.

Wet Rot

Wet Rot can be commonly found on the exterior of a property where your timbers’ moisture content or (any other permeable materials) reaches 30% - 50%. The high levels of moisture in the wood attracts a fungus - most commonly being ‘Coniophora Puteana‘ (also known as Cellar Fungus) which

Wet rot destroying timber on the outside of a property

feeds on the dampened wood, and will inevitably destroy it.

Wet timbers are usually a result of an external leak or water ingress from plumbing, guttering or downpipes.

Once discovered

Should you discover Wet rot, firstly, you should investigate for any leakage that may be causing the problem. If a leak is found, fixing the leak as soon as possible should be made a high priority to help prevent any further damage.

Removing the cause of the moisture will be put a stop to Wet Rot as the fugus requires the moisture to be able to grow.

You should now replace the timber by the Wet rot with pre-treated timber, and any remaining, unaffected timber must be treated with an effective fungicide.

Ways of identifying Wet Rot:

  • Timber appears soft and spongy

  • Black fungus appears on the wood

  • Paint work can be affected by the fungus (in some circumstances)

  • Wood is cracked or crumbly (This a late stage of the decaying process and the timber would have dried out)

Help can be found online, or should you wish, feel free to contact us and we will be more than happy to point you in the right direction to resolve the problem.

Dry Rot

Dry rot occurs when airborne spores land on timber that contains moisture levels of around 20%. These spores begin to feed on the dampened wood and develop into a fungus. Dry rot fungus, unlike Wet rot, has the ability to spread, and can damage all the wooden material on a property, should the conditions suit.

The best type of conditions for Dry rot to grow is a damp, warm and poorly ventilated environment. Therefore, it is good practise to frequently check warm and dark areas within your property, such as loft and garage spaces, to ensure moisture is not in the air or that dry rot is growing.

Once discovered

Should you discover Dry rot, you should first check to see if there is an external leak that may have access to the affected area e.g. waterpipe leaks or damp coming through the walls, and then carry out the appropriate repair work.

Second, you should remove all moisture from the room and allow the timbers to dry out. - A dehumidifier is a good tool to use for extracting moisture from the air within an enclosed environment.

Once the area and the affected timbers have be dried, any damaged wood must be removed and replaced as they would be deemed unsafe due to being eaten by the fungus. Any new timber added to the area should be pre-treated timber, and any remaining, unaffected timbers must be treated with an effective fungicide.

If you’re unsure how to proceed with Dry rot, Help can be found online, or should you wish, feel free to contact us and we will be more than happy to point you in the right direction to resolve the problem.

Early signs and how to spot Dry rot

An early sign of moisture in your property is condensation on the inside of windows. This is caused by the warm, moist air turning into water on the colder surface of your windows.

You can also tell if there is any moisture in the air by simply smelling. If the air appears to smell damp, there is a good chance dry rot may be growing.

White, fluffy ‘cottonwool’ mycelium developing under humid conditions.

Ways of identifying Dry Rot:

  • White, fluffy ‘cottonwool’ mycelium develops under humid conditions.

  • In sunlight, the fungus has a lemon almost yellowish tinge to its reflection.

  • Deep cracks across the timber’s grain along with evidence of mycelium growth on the wood.

  • Wood will be brown in colour and will crumble due to a lack of structural integrity.

  • A large flat mushroom-like fruiting bodies may also be visible on the wood. (In some instances)

For more information on Wet rot or Dry rot, please do not hesitate in contacting us here at South Yorkshire Surveyors.

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