Rot Treatment
Dry and wet rot are both caused by fungi, and they can seriously damage any timber infected. Dry rot is by far the most serious, as it is able to travel through building materials other than wood, so can spread very quickly. Rot treatment is important in all cases.
The most vulnerable part of timber to rot is the sapwood, which is the outer area of the tree. It contains food, whereas the heartwood is the older timber in the centre of the tree. The heartwood is more resistant to decay.
Dry Rot
Dry rot is caused by the fungus Serpula lacrymans which attacks the cellulose of the wood, causing the timber to darken and crack. The cellulose is broken down to basic sugar components and used by the dry rot fungus for food. This leads to the wood shrinking, which eventually causes cuboidal crack to appear.
Dry rot fungus is a mushroom colour, although lilac and yellow patches appear in less humid conditions. In high humidity white mycelium develops. The fruiting body of the fungus is soft and orange. The area of dry rot often has a musty odour.
Dry Rot Treatment
Professional timber treatment companies are recommended for dry rot treatment. The most important aspect of rot treatment is to dry the damp timber, as the fungus can only develop at roughly 20% moisture levels and above. Common sources of damp include leaking appliances, roofs or rising damp.
Once the source of damp is removed the dry rot fungus will die, as long as it is allowed to dry out. Natural ventilation is preferred to a dehumidifier as this can sometimes warp the wood. If the wetness is caused by rising damp, silicone wood preserver can be used to replace the damp proof course of a house if it has broken down.
Dry Rot Repair
Dry rot repair and control also often involve secondary measures to prevent against re-infection. The wood can be treated with a fungicide, and masonry sterilisation is recommended. Masonry sterilisation involves applying a water based fungicide spray to building materials close to the site of infection. This will prevent the dry rot fungus from spreading. Badly affected wood may need replacing.
Wet Rot
Unlike dry rot, wet rot fungus is unable to travel across other building materials. This makes this infection less serious than dry rot. Rot treatment is still essential as it can seriously damage timber.
Wet rot is not caused by one species; a number of different wet rot fungi can cause this problem. Examples include Cellar fungus (Coniophora Puteana), white pore (Fibroporia Vaillantii) and white rot (Donkioporia Expansa).
Wet rot fungus is broadly categorised into two areas: brown and white rot. This does not refer to the colour of the fungi; instead it refers to the colour changes the wood undergoes when infected. Brown rot causes a darkening of the wood and cubodial cracking, whereas white rot leads to a lightening of the wood and damage along the grain.
Wet Rot Treatment
Treatment of wet rot fungus is similar to dry rot; the most important measure is removing the source of damp. Wood preserver can be applied as a wet rot treatment to stop further infections and prevent it spreading.