DRY ROT AND WET ROT CONTROL

Problem

The most frequent, and the most serious, cause of damage to building timber is fungal decay, commonly known as Dry Rot or Wet Rot, and this can affect all timber, historic or modern. Dampness combined with lack of ventilation provides the ideal conditions for fungal attack on timber.

Solution

The nature and biology of fungal decay makes it vital to locate and eliminate the underlying source of moisture behind the outbreak. Roofing failures and leaking gutters are particularly damaging allowing water to spread over large areas before being discovered. Dry rot surveying may require exposure work before the complete extent of the outbreak can be determined.

Repairs and Fungicidal Treatments
Peter Cox technicians will replace defective timbers and undertake repairs where necessary to retained sections, including structural and decorative timber. All retained timber is treated using the latest fungicidal formulations to prevent further infection. Where necessary adjacent masonry is irrigated and surface sprayed with a biocide.

• Modern, water based micro emulsion fungicides and biocides
• Low odour, low hazard and HSE approved
• Treated rooms can be re- occupied after just one hour
• Generally surface sprayed but also applied by brush, injection and in gel or paste formulations

The Different Species of Fungi
Dry Rot and Wet Rot are wood destroying fungi (Basidiomycetes) which attack timber in order to extract food (cellulose or lignin) to maintain growth and the generation of spores.

Dry Rot (Serpula lacrymans)
The true Dry Rot fungus is the more serious requiring fast specialist action to avoid extensive damage. It is malignant and will spread even through thick walls in search of timber to attack. Affected timber is brown, dry and brittle with cuboidal fractures and can be crumbled by hand.

It requires over 20% moisture level for spore germination. Fine greyish hyphae strands develop from the spore spreading to form mycelial growth which varies from grey to pure white in wet conditions. Sporophores or fruiting bodies give off millions of spores in the form of red dust.

Wet Rot
Wet rots are a common cause of structural defects and there are number of species which attack timbers in buildings. They generally thrive on a higher timber moisture content than dry rot but do not spread through masonry and growth ceases when the moisture is removed.

Attacked timber is either darkened or bleached depending on species and is left in cuboidal or longitudinal cracks.

The species most commonly found is Coniophora puteana (cellar fungus). Other species include Fibroporia vaillantii (mine fungus) and Phellinus spp.

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