Over the last two months of this series, we’ve looked at two of the most common and significant timber defects present in British homes – wet and dry rot. Now, in our last article on the timber defect theme, we’ll take a look at insect infestation, which can be just as devastating to your home.
The visible signs of woodworm are small holes in the timber, resulting from the emergence of the adult beetles. If there is powder beneath the hole, then it is most likely fresh and ‘live’, and will require treatment.
The eggs are laid just under the surface of the wood, and when the grubs hatch, they eat their surroundings. After pupation, they come to the surface as adults, and the cycle begins again.
Insects need similar conditions and characteristics to wet and dry rot. The insect larvae particularly thrive in damp timber and the hatched larvae are attracted to the starches and sugars contained in the wood, just like the fungus.
The following is a list of the most common insects to cause this type of issue in Britain:
Common Furniture Beetle
A small dark reddish brown beetle, damage caused by these insects is the most commonly found. The beetles attack the sapwood within European hardwoods and various softwoods and outbreaks are considerably more severe in damp timber.
These are chocolate brown and focus mostly on hardwoods, like Oak. They are commonly found during the emergence period, which spans from mid-March to the end of June, and can have patches of yellow hair. Softwood is not entirely safe from these beetles though – rotted timbers can be susceptible particularly if in contact with hardwood.
Powder Post Beetle
Similar to the common furniture beetle, but differentiated by requiring a high starch content in the timber – which can be influenced by methods of handling and storing logs or of drying after conversion.
House Longhorn Beetle
Characterised by their long antennae, these are large, brown to black beetles that are very localised to the South East of England – particularly around Camberley. They are not to be underestimated and can create dust-filled tunnels in bark and sapwood.
Dry timber is considered immune to attack, as with dry and wet rot. So the first port of call at an affected property is to bring the timber moisture content down below 15%. Efforts will need to be directed towards increasing the ambient temperature of the timber using background heating and introducing additional ventilation. As most timber defects are found in the roof space, the latter will be perhaps the most important of these.
Additional measures include chemical treatment, heat treatment, pheromones and ultra-violet light.
As with any property defect, the best advice is always to speak with an independent chartered surveyor – not initially a remedial treatment contractor who may be biased in his assessment. Your surveyor will advise you from a neutral, professional stand-point and arm you with the information you need to proceed safely and cost-effectively.