Most fungi that affects wood produces spores. Microscopic in size, they serve a similar purpose to the seeds of plants. They can be transported long distances by wind, natural air currents and carried by birds and animals. Moisture and a timber host are vital for germination. Should spores fall on timber with a moisture content of 28 – 30 %, then germination may take place with the production of fine thread like structures known as hyphae.

Provided the moisture levels remain high, the hyphae enter the cells of the timber causing a breakdown of the cellulose.

The type of fungi generally located in the timbers of structures, usually reside in poorly ventilated sub-floors, the sub floor area below wet areas, exterior timbers (especially in coastal areas) and in areas that retain water in the soil.
Timber type and durability are factors along with the temperature and environment. Destruction of affected timbers will vary with the symptoms involved.

Fungal decay releases carbon dioxide as part of the natural decay process, making the timber far more attractive to termites. Failure to rectify the problem may well lead to future termite attack. Removal of the moisture source usually alleviates the problem

Externally, wood decay caused by fungi commonly establishes growth in unsealed, split, exposed timbers. Timber joints and/or sections that have gaps due to shrinkage or poor craftsmanship, and ends inadequately sealed could have established fungal decay that is not visible. This decay may advance to extensive fungal decay within a short period of time. To minimise further decay it is recommended that all decay-damaged timber be removed, all gaps sealed with a suitable sealant and/or paint, using a primer and an undercoat, as a matter of priority.

DECAY FUNGI
Wood destroying fungi needs three things to survive: air, water, and food. Since we can't eliminate air and their food is the wood in our homes, the only mechanical control mechanism available to us is the elimination of water. Water is the enemy of wood! Few species of timber are safe from decay fungi caused damage, including species such as redwood and cedar. Decay can occur in untreated wood in direct contact with ground, concrete, or timber exposed to a constant source of moisture such as rain seepage, plumbing leaks or condensation. Wood kept dry will never decay!

BROWN (CUBIC) ROT
Brown rot commonly attacks softwoods, staining the wood dark brown. In advanced stages of decay, wood attacked by brown rot becomes friable and splits appear across the grain giving the wood a "checkerboard or cubed" appearance. Affected wood will almost certainly be weakened structurally in a relatively short period of time. Once brown rot has extracted all of the nutrients from the wood the wood may become dry and powdery. This leaves the impression that dry wood has rotted (dry rot) but in reality it is an old infestation of brown rot. Brown Rot (Cubic Rot)

Brown (cubic) Rot

WHITE ROT
White rot attacks the cellulose and lignin in the wood giving the wood an off-white appearance. In the later stages the wood becomes spongy to the touch. White rot typically attacks hardwoods and lacks the cubical checking appearance of brown-rotted wood.

White Rot

In all cases of timber decay, once the moisture source has been stopped, the damage also ceases.

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