Dry Rot

Dry Rot Is a wood destroying fungus causing the most serious timber decay in buildings, often resulting in extensive damage. It has the ability to grow through brickwork, mortar and behind plaster.

It can be difficult to detect in early stages as it may develop out of sight. Some indications of possible dry rot may be the softening of wood in some areas, shrinkage and distortion and a distinctive "mushroom" odour. The timber decayed by dry rot is characteristically dull brown in colour with deep cracks across and along the grain forming cubes up to 50mm in size; similar in appearance to charred wood but not as dark. The timber becomes lightweight and will crumble. Sheets of silky, cotton wool like, white mycelium may be present. Where exposed to light these may have a lemon or lilac tinge. Strands up to 8mm thick may spread from infested timbers. These transport moisture from damp areas allowing the fungus to spread to dry wood in other areas not satisfactorily ventilated.

When conditions are suitable the fungus may form a pancake shaped fruiting body; yellow ochre with white edges when young, darkening to rust red when mature. The centre portion will explode and produce a mass of rust red spores, which will often form a red dust cover over the surrounding area. The destructive nature of this fungus should not be under estimated as it grows in dark, damp places, out of sight, until it produces a fruiting body which will disperse millions of spores. If the fruiting body is allowed to disperse its spores huge amounts of damage will occur.

DWCs surveyors will endeavour to identify the origin of the dampness which is a very important part of the survey procedure. Any rotted timber must be removed and replaced with treated timber. Insitu timbers must be treated with fungicidal spray or timber paste or injected with fungicide pellets.

The dormant fungus can survive up to ten years in damp masonry. The infected masonry must also be treated with fungicidal wall solution.

Wet Rot

Coniophora puteana wet rot or cellar fungus

Wet Rot is a general term applied to many species of fungus, all of which will cause timber decay. They can be divided into two groups; brown and white rots.

They vary in severity of damage but none possesses the ability to pass through inert material and spread to other damp timbers like Dry Rot. Thus they are found in localised areas where they are exposed to considerable amounts of water ingress. Externally exposed timbers, timbers in contact with wet soil or masonry, or timbers subject to a damp atmosphere can all suffer from Wet Rot.

Brown rots will result in the darkening of timber and cause cracking leaving cube like shapes which will also crumble. The cube like shapes are generally smaller than those associated with dry rot and therefore it is important that these characteristics alone are not relied upon for identification purposes.

White Rot may bleach the affected timbers leaving them pale in colour. The wood will develop a stringy, fibrous appearance, and although may be easily crushed will not crumble.

Colours of associated mycelium strands and fruiting bodies will vary depending on which type of fungus causes the damage.

The remedial measures required for both brown and white rots but most importantly excluding dry rot are the same in that treatment involves eliminating the source of damp and/or perhaps replacing the timbers with brick or concrete substitute where practical. Insitu timbers may be treated with a dual purpose fungicide and insecticide for long term protection.

 Damp Proofing Areas