Wet rot can occur more frequently than dry rot, however it is usually less serious. The deca is typically confined to the area where timber has become (and remains) damp for prolonged periods of time. Outbreaks of dry rot and wet rot begin in similar ways. Wet rot is not as destructive as dry rot; however it can, and does, lead to severe structural damage. Some of the most common contributing factors to the outbreak of wet rot are:
- Unprotected timbers which remain in direct contact with a source of moisture;
- Poor sub-floor ventilation beneath suspended floors;
- Leaks generating from plumbing and/or domestic appliances.
Whilst there are a number of types of wet rot, the most commonly occurring species are Coniophora Puteana and Poria Vaillantii. Whilst each fungus has its own unique features, the general appearance and treatment often remain similar. Whilst most wet rot fungi produce strands, it is typically confined to the area of dampness. Although in rare instances, mycelium can develop extensively, it does not usually spread into the walls nor exceed further than its immediate food source, unlike dry rot.
Identifying Wet Rot
The fruiting bodies of wood-decaying fungi can produce large amounts of microscopic spores, which, when dispersed by air circulation, can affect damp, untreated timber. These spores infect the untreated timber by pushing out a hollow tube, which grows and branches to form a mass of hyphal threads called Mycelium. This continues to develop within the timber, breaking down the wood for food. The timber will usually darken in colour and develop a cracked-like appearance. Eventually, the timber will lose its strength and stability and, in some cases, become unsafe.
Characteristic Features of Wood Destroying Fungi
Type of Decay: Dry Rot
- Fungus: Serpula Lacrymans
- Effects on Wood: Rotted wood shrinks and splits into cubical pieces by deep cross cracking. Generally occurs in damp conditions. Spore dust is a light rusty colour.
- Visible Strands: Strands are grey, sometimes as thick as pencil, and become brittle when dried.
- Other Growths: Often occurring in damp conditions, soft white cushions or silky tassels can form. In drier conditions, silver/grey sheets usually displaying patches of lemon yellow and tinges of lilac.
- Fruit Bodies: Fleshy, soft but rather tough; shaped liked pancakes. A spore bearing surface with a reddish brown tinge, with wide pore or labyrinth ridges and a white, outer margin.
Type of Decay: Wet Rot
- Fungus: Coniophora Puteana
- Effects on Wood: Causes darkening and longitudinal cracking. Cross cracks are often covered by a thick surface of relatively sound wood; often occurring in very damp conditions.
- Visible Strands: Strands are slender and usually thread like. In early stages can appear yellow in colour, developing into a deep brown/nearly black colour when mature.
- Other Growths: Occasionally very thin, skin-like growths; can appear yellow or dark brown. Commonly occurring beneath impervious floor coverings.
- Fruit Bodies: Rarely found in buildings. Has a sheet-like shape; the spore bearing surface is often an olive-brown colour.
Type of Decay: Wet Rot
- Fungus: Poria Vailantii
- Effects on Wood: Rot is similar but less widespread than that of dry rot. Various species of Poria can occur in houses, most of which require more moisture than dry rot.
- Visible Strands: Strands are often white or whitish; seldom thicker than twine and remain flexible when dried.
- Other Growths: White or cream sheet, or fern-like growths.
- Fruit Bodies: Shaped like sheets or plates and are white in colour. The spore bearing surface is also often white, showing numerous, minute pores.
Type of Decay: Wet Rot
- Fungus: Phellinus Contiguus
- Effects on Wood: There is no cubical cross cracking. Bleaches the wood, which eventually develops a stringy, fibrous appearance.
- Visible Strands: There are no strands.
- Other Growths: Brown, tufted growths, which are commonly found within voids or on the surface.
- Fruit Bodies: Tough, brown growths; often elongated. The surface is covered with minute pores.
Protecting your home against possible outbreaks is strongly recommended. To help prevent wet rot, it is advisable to ensure that all external timbers, including doors and windows, are protected from rainwater. One must also undertake regular maintenance and the re-application of timber preservatives and paints to ensure sufficient protection against adverse weather conditions.
Other recommendations include: periodic checks to gutters and downpipes ensuring that all are free from defects and leaks; ensuring that there is sufficient sub-floor ventilation to the property, and that this remains unblocked and free from debris; and ensuring that all new timbers introduced to the property are isolated from masonry and/or damp substrates with the use of physical DPC. Where possible, it is strongly recommended that any replacement structural timbers are installed using pressure treated timber.
Specialist timber treatments should be carried out in strict accordance with the PCA Code of Practice for Remedial Timber Treatment by an experienced and qualified technician.
Biocraft South West use specially formulated preservatives that allow for the successful eradication of wet rot. To arrange a survey of your property or for further information regarding timber decay contact us today. We cover Andover, Bath, Bristol, Chippenham, Devizes, Marlborough, Oxford, Salisbury, Swindon, Trowbridge and Warminster.