Gwynne Anthony 2020

ART506 Dissertation 2019. Anthony Gwynne . 124 Causes of timber decay K3: Wet rot and dry rot (www.timberwise.co.uk/) What is the Difference Between Wet and Dry Rot? Dry rot is the most serious form of fungus decay in a building, spreads onto and destroys much of the timber. On the other hand, the wet rot fungus occurs more frequently but is less serious, the decay is usually detained to where the timber becomes and stays wet. The Wet rot fungus tends to grow on porous surfaces, for example, timber with a high moisture content of around 50% while for dry rot to grow moisture of around 20% needs to be present. If left untreated wet rot can cause major structural problems as it can lead to weakened timbers. For moisture content to be suitable for wet rot growth there has to be a source of constant moisture – this could be as a result of defective plumbing or damaged guttering. Wet rot cannot spread through masonry and will cease to grow when the source of moisture is taken away. Due to the parts of the building that tend to have the correct moisture levels, for example, underfloor areas, dry rot can often cause significant damage before the homeowner is aware that there is even a problem with dry rot in the property. K4: Wood boring insects (www.spab.org.uk/advice/wood-boring-insects) They are species, including certain beetles ('woodworm'), that feed on wood and may seriously damage building timbers. In the UK, they include the furniture beetle (Anobium punctatum), closely related death watch beetle (Xestobium rufovillosum) and other, more minor, decay insects such as the house longhorn beetle (Hylotrupes bajulus), which is found in some southern areas. It is the beetle larvae (grubs) that burrow into wood. Eventually the larvae pupate, and adult beetles emerge to mate via flight holes or fissures. Females lay eggs in crevices, maybe old flight holes, to repeat the cycle. Termites, another form of wood-boring insect, could gradually become more prevalent in this country due to global warming. Wood-boring insects, like timber-decaying fungi, only establish themselves where dampness exists. Beetle damage in buildings is usually confined to sapwood, although heartwood is vulnerable too if fungus is present. Sometimes active death watch infestation is inadvertently reported in dry timbers where dust is dislodged from old flight holes, perhaps by building work. Good preventative maintenance and moisture monitoring can avert dampness and, therefore, ensuing damage caused by woodborers. However, over-reliance should not