DRY ROT AND WET ROT CONTROL

Dry Rot

Dry Rot is a fungus that attacks building timbers. It can damage both old and new timbers. This fungal decay, together is the most serious form of damage to timbers in buildings.

Dry Rot can spread rapidly through brickwork and concrete if it is not treated, and can cause widespread structural damage. ‘Serpula lacrymans’, the true dry rot fungus thrives in the dark and in unventilated areas. It often grows behind panels and under floors.

Dry rot symptoms

Dry Rot is malignant and will travel rapidly, even through walls, to attack timber.

Remedial action is urgent and you should contact Peter Cox immediately if you see the white or silver/grey growth or reddish brown fruiting body (mushroom) or the red dust of spreading spores. It is most important to get a survey straight away and tackle the problem.

Infected timbers need to be removed and the full extent of the attack exposed before the preventative treatment for dry rot is put in place.

Summary of Dry Rot symptoms include:

• Spore dust, rust coloured seen near fruiting bodies.
• Cracking or shrinking of the timber.
• Timber becomes dry and brittle, may darken in colour and will crumble at your touch.
• White, fluffy 'cottonwool' growth appears under humid conditions.
• Characteristic dry rot smells like mushrooms can often be detected.

Dry Rot is not likely to be found in timber that is always wet and or constantly dry.

A dry rot survey will identify the problems and potential solutions

Dry Rot treatment

Although it is called ‘Dry Rot’, dampness is a key factor. Over 18% moisture level is needed for spore germination. Poor roofing, leaking gutters, rising damp, water leaks and poor ventilation can all contribute to the problem – so dealing with any sources of moisture is the first set of actions.

Peter Cox will remove and replace infected and defective timbers. We will make repairs to structural and decorative timber where needed. All retained timber is treated using the latest fungicides to prevent further infection.

Adjacent masonry can also be treated with modern, water-based micro-emulsion fungicides and biocides. These are HSE approved, low hazard and low odour. After just one hour rooms that have been treated can be re- occupied.

Wet Rot

Wet Rot is another fungal ‘infection’ of timber. Again it affects the structural strength of timber and it can damage a building. Compared with dry rot, wet rot is not so serious, requires a higher timber moisture content, and does not travel through masonry. Growth ends when the dampness is removed.

Wet Rot decay happens when there are very damp conditions, with high levels of moisture and poor ventilation.

Wet Rot generally requires a higher timber moisture content than dry rot, generally over 30%. There are several wet rot fungi including:

• Cellar fungus (Coniophora puteana) usually found in damp basements, under floors and in skirting boards. Causes timber to darken and produce cracking both along and across the grain of the wood. It prefers very damp conditions in areas like basements, leaking roofs and wood floors where there is insufficient ventilation.
• Mine fungus (Poria vaillantii) causes wood to shrink and split into cuboidal sectors. The strands are white, sometimes fern-like.
• Phellinus contiguous which bleaches wood, which becomes fibrous and stringy. This is a common type of decay in external joinery timbers such as door and window frames.

Wet Rot treatment

First of all it is important to identify and remedy the cause of the dampness. Again, water ingress through faulty roofing, leaking gutters, penetrating or rising damp, plumbing/appliance leaks can cause excessive moisture, and cause problems if combined with inadequate ventilation.

Therefore the first step is to deal with the sources of dampness.

Defective timbers will be replaced. Other structural and decorative timber will be repaired. As with dry rot, all timber is treated using the latest fungicides to prevent further infection. If necessary, masonry can also be treated with modern, water-based micro-emulsion fungicides and biocides.

Dry Rot or Wet Rot survey

A Peter Cox survey report will evaluate your property for dry rot and wet rot symptoms, and will inform you if and when early action is required. We will identify the type of fungal decay if and where they are present.

Expert advice will be given if dry rot or wet rot occur in structural timbers (such as roof timbers and floor joists). The implication for structural integrity will be assessed.

A cost-effective work specification will be produced which will address dealing with dampness, replacing or repairing the infected timber, treating the timber and masonry as needed and dealing with structural issues to protect the property for the future.

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