Dry Rot (Serpula lacrymans) is by far the most serious and damaging of wood rotting fungi and is caused by damp conditions and lack of adequate ventilation. This fungus has the ability to travel through brickwork and plaster in search of further sources of moisture and causes millions of pounds worth of damage to properties annually.
Look out for fungal strands along the timber and through or along any walls. These strands can become quite dense forming a mass like cotton wool. The final part of the fungal life cycle is the formation of a large mushroom like fungus that produces millions of new air-borne spores aiding rapid distribution. It is quite common to find that substantial damage has been caused before the outbreak is noticed. There is often an accompanying distinctive dry musty smell.
Treatments are similar to that of wet rot, the main exception being that the treatments must extend at least one metre beyond the last visible signs of growth and decay. This often involves the removal of renders and plasters, cutting back of decayed timbers to beyond area of infection and inserting new treated timbers as required. Masonry and timbers would typically receive chemical treatments.