Fungal (wood) decay is caused by certain fungi which destroy the cellular structure of timber and often lead to considerable damage to timbers in a building structure and is therefore important to report on, especially in Pre-Purchase pest inspection reports (refer to Code of practice for prior to purchase pest inspection and Australian Standard 4349.3
Wood decay will occur when there is a high level of moisture present. This could be caused from poor ventilation, plumbing leaks or drainage problems.
High moisture can also attract other pest problems such as termites, borers, cockroaches and rats, the latter 2 posing significant health risks if left unchecked.
Timber in service will not decay if moisture levels are kept below 20%. Your Austrapest technicians will identify excessive moisture in the subfloor, and may recommend the installation of electric fans and vents if applicable, as well as maintaining proper building maintenance. For more information see our page on building maintenance and subfloor ventilation.
Types of Fungal Decay
- Brown rot fungi will leave wood darker in colour and cracked across the grain, producing large cubes of wood.
- White rot fungi leaves exposed surfaces looking fibrous. Hardwood is more susceptible to white rot fungi than softwood.
- Soft rot is a mixture of fungi and bacteria that live in the soil.
Some timbers are more durable in service (i.e. used as building timbers). When timbers are treated and in contact with the ground, they are still susceptible to white rot fungi. Decay of timbers in service will often be most pronounced when in contact with the ground (e.g. poles and fence posts). No untreated timbers can be regarded as completely immune to fungal decay.
Mould fungi are the cause of allergens in humans but their activity on timbers is only superficial and they do not decay wood – the significance of mould fungi is that it indicates a moisture problem.
Dry rot fungus is an incorrect term. It can be found in Melbourne but unlikely in Sydney due to our higher temperatures. Mildew and non wood decay fungi is commonly known as mould and is not considered a Timber Pest. The quality of air under a house can impact on the health of the occupants contributing to household allergies and respiratory problems