Dry Rot

This is the worst type of wood-destroying fungus that can affect timbers within a property. Dry rot is best known for its ruthless destruction of timbers in buildings, and is classified as a brown rot.

Latin name is Serpula lacrymans (creeping tears).

It is important to establish if timber decay has been caused by dry rot or another wood-destroying fungus such as one of the wet rots. This is because dry rot has the ability to travel through other building materials rather than timber, giving outbreaks the potential to spread quickly through a building. It is for this reason additional procedures (e.g.plaster removal sub-floor clearance, and a more destructive survey to clarify extent of outbreak and masonry sterilisation) often have to be taken when treating dry rot outbreaks over and above those necessary when dealing with outbreaks of other wood-decaying fungi.

The common identification markers of dry rot include:

  • Timber that darkens and cracks in a ‘large cuboidal’ manner due to shrinkage.
  • A silky grey mushroom coloured skin, that coats the timber, with tinges of yellow and lilac, which can develop under less humid conditions. This skin can be peeled just like a mushroom can.
  • A White  ‘cottonwool’ mycelium develops under humid conditions. Droplets of moisture may form on the growth.
  • Thick Strands develop in the mycelium, when dried these strands become brittle and can crack when broken.
  • The fruiting bodies are a fleshy soft pancake or bracket with a beige edge and a red brick coloured centre.
  • The spore dust is rust red coloured and can be seen on the surfaces around the fruiting body.
  • During decay a mushroom odour is noticeable.

Classified as a brown rot


Treatment generally involves the removal of affected timber and its associated growths(strands and mycellium as well as any fruiting bodies), then the source of moisture must be found and rectified, any affected timbers are replaced with new pre-treated timbers, the plaster on walls in the immediate area may have to be removed if it is found that there is an element of damp to theses walls as it can spread through damp masonary, as the growing strands tend to grow at the rear of plaster on its quest for more viable timber to devour, the affected walls are sprayed with a masonary biocide and on some occasions the walls are irrigated also with a biocide, any subfloors are also spray treated and then any remaining timbers within the treatment area can also be treated, usually with a water based coarse spray fungicide.

Most of the chemicals we use on our treatments are either water based or glycol based, and we always strive to use as least amount of chemicals as possible.

If you think you may have dry rot then contact our office and we will be happy to arrange for a more in-debt survey.

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