Dry
Rot
Latin name Serpula lacrymans
Common name Dry Rot Fungus
Habitat Mostly softwoods.
General Information Major building decay
fungus often causing extensive damage. Brown rot
which typically occurs on wood embedded in, or in
contact with, wet brickwork. Sensitive to high temperatures
(over 25"C) and drying, and therefore rarely
found on exposed timbers or in situations where
fluctuating conditions are likely (e.g. well ventilated
sub floors and roofing timbers). Able to grow through
masonry, though cannot feed on these. Strands can
transport moisture from damp areas, allowing spread
of fungus to dry wood in unventilated conditions.
Appearance of fruit-body may be first indication
of outbreak. Damage characteristics Decayed
wood has dull brown colour typically with deep cracks
along and across grain. Light in weight and crumbles
between fingers. No skin of sound wood.
Fungal characteristics
Mycellum Silky white sheets or cotton
wool-like white cushions with patches of lemon yellow
or lilac tinges where exposed to light. In less
humid conditions, forms thin, felted grey skin.
During active growth, advancing hyphal edge forms
silky fringe. Tears in direction of growth. Strands
White to grey, branching, sometimes
as thick as a pencil. Brittle when dry. Fruit-body
Usually at wood-wall joints; rare on exteriors of
buildings. Tough, fleshy, pancake or bracket shaped.
Centre is yellow ochre when young, darkening to
rusty red when mature owing to spore production.
Covered with shallow pores or fold Edges white or
grey. Spores Profuse
and may settle as fine layer of reddish brown dust
on horizontal surfaces.
Wet
Rot
There are many fungal species causing wet rot;
the same remedial measures are required for all
of them. They cause a darkening (the timber (brown
rot) or bleaching (white rot). Some types are
only rarely seen in buildings.
Soft Rot can be regarded as a superficial form
of wet rot. It is more usually found in timber
in ground contact.
Latin names Coniophora
puteana and c. marmorata Common name
Cellar Fungus
Type of decay Brown rot
Habitat Softwoods and hardwoods.
General Information Commonest cause of
decay in woodwork which has been soaked by water
leakage.
Damage characteristics Wood darkens with
cracks along and across grain, but usually less
deep than those caused by Serpula lacrymans. Where
conditions cause drying of wood surface, and apparently
sound skin of timber often remains which may crack
longitudinally as decay progresses beneath. Freshly
colonised wood usually shows yellow discolouration.
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