The most common wood-rotting fungus is serpula lacrymans, or dry rot. Dry rot can attack wood with moisture content between 20-22%.
Dry rot needs damp conditions to thrive. Other factors aid its development, such as constriction and lack of ventilation, whereas temperatures below 18-20°C and above 30°C help slow down its spread.
When all development factors co-exist, filaments from the fungal spores colonise the wood and form what is known as mycelium. Surface dry rot forms soft white cushions and fungal strands, which spread out over several meters until they reach sufficiently damp areas for the fungus to thrive. Dry rot can thrive on any type of wood although softwoods tend to be more vulnerable. Its destructive action leaves the wood dry and brittle.
Dry rot can sometimes be confused with cellar fungus. However, cellar fungus attacks wood with a higher moisture content, above 40%, which makes it less common. Wood attacked by cellar fungus decomposes into fine, light-coloured fibres.
Other types of wood-rotting fungi require the wood’s moisture content to be far higher for them to proliferate, above 50%. These fungi leave wood with a sponge-like appearance.
TREATING WOOD-ROTTING FUGNI
Each fungal infestation requires specific treatment involving complex operations, which can only be carried out by companies that are specialised in this area.
Renovation involves two types of intervention:
- Restoring a building to a sound state by eliminating all sources of damp, introducing effective ventilation, waterproofing walls and parquet flooring, and more.
- Treating wood-rotting fungi following the preparatory and treatment phases outlined underneath.
- Remove coatings which conceal fungus
- Chip away at plaster and strip it away from joints
- Blowtorch the affected area of the masonry and brush it clean of any fungal fructification
- Clear away rubble in line with the regulations in force
- Locate affected timber
- Hack out affected timber
TREATMENT PHASE: floors and masonry
- Inject KOATMERULE into the affected area and 1 metre to either side of the area
- Spray the affected area
Other wood-rotting fungi:
- Spray all the affected surfaces
Preservative treatment for remaining wood:
- Inject the remaining sound wood a metre beyond the affected area
- Double the number of injections for lap joints, including width wise if the cross section of the wood is large enough
- Spray over each side and up to 1 metre beyond the affected area