How do Wood Boring Beetles Cause Damage?
It might surprise you to know that it isn’t the beetle itself that does the damage, but the larvae. The adult beetles will lay their eggs in cracks or rough timber throughout the house. When the eggs hatch, the larvae burrow into the timber and eat all the cellulose inside, excreting a fine powdery sawdust (or frass) as they tunnel into the wood. Wood that’s been softened by fungal decay is easier for the larvae to digest, so they will often aim for this pre-weakened wood. Once they mature, the adult beetle emerges from the ‘flight holes’ to find a mate, breed and restart the whole process. Depending on the specific species of beetle, this whole process can take between 2 – 11 years!
How Can You Tell if the Timber is Damaged?
Normally the first signs of damage you’ll see are the ‘flight’ holes made by the larvae. When these become visible the adult beetles have already left, and the timber is already damaged. But if you can spot these early you might be able to treat the infestation thoroughly, which would stop the need for repairs. Another sign is the fine powdery dust the larvae leave behind, which can often be caught in cobwebs, or left in small piles under the timber. If the timber is heavily damaged, tapping it gently can cause a lot of it to fall from the timber.
There are other ways to check if your timber has been damaged by woodworm. Invasive inspections (which include moisture testing, decay detection and sound testing), probing or non-invasive x-ray tomography can all be used to establish if there’s any hidden damage to the structural areas of your home. Unfortunately, some timbers may appear reasonably fine on the surface, but have damage much deeper within the timber.
How do I Know Which Species is Damaging my Timber?
As we mentioned before, there are a few different types of woodboring beetle, so it’s important to know which type you’re dealing with. The most common types found in the UK are:
• Common furniture beetle (the most common)
• Deathwatch beetle
• Wood boring weevil
• Powder Post beetle
• House Longhorn beetle
• Old house borer
Each prefers a slightly different type of wood, and works in a slightly different way. For example, the common furniture beetle likes to eat softwoods and hardwoods and can usually be found in furniture as well as in structural elements of your home. The Powder Post however bores more deeply into the timber, preferring hard sapwood that’s less than 10 years old.
Identifying which species is giving you trouble a can be a bit tricky, but there are a few ways to do it. You can look at the size and shape of the flight hole (for example a common furniture beetle leaves small flight holes that are around 2mm in diameter. You can also listen for sounds. The deathwatch beetle hit their heads on a substrate to make a tapping sound that attracts mates, so if you can hear a tapping sound, that’s probably your culprit.
Fun fact – the tapping of a deathwatch beetle has long been associated as a harbinger of death, since you can hear it best on quiet nights in the rafters of old houses, or in silent bedside vigils for the dying. That’s how it got its name!
What do I do?
If you think you have a woodworm infestation, the first thing you need to do is have the extent of the infestation assessed by a qualified professional. You can often tell if its active because there will be fresh frass or recent, clean flight holes. But it’s not always that easy, and it can be tricky figuring out if the damage is historic or ongoing. Some parts of the structure (like floorboards or roof timbers) might not be visible to you, so you’ll only notice the damage when you go to do other works.
Next comes treatment. This is usually done by applying an insecticide or biocide – brushing, spraying or dipping the timbers to ensure thorough application. This is best done during spring to late summer, when the adults emerge from the holes. But if you have any larvae that are deep in the wood (like that deathwatch beetle) then surface treatments might not be as effective. If this happens, you might need other methods like drilling and applying the treatment into the timber, or even having the areas fumigated. In the worst-case, heavily damaged timber might need replacing or reinforcing.
At Harrison Clarke, we have a team of experienced and competent surveyors who can advise and assess your property, either before you buy it or if you discover damage during other works. So if you think you’ve got a case of woodworm, give us a call on 023 8155 0051, and our experts will be happy to help.
For more expert advice on surveying and property matters, check out our range of informative videos on our website or YouTube channel. Harrison Clarke Chartered Surveyors is here to guide you every step of the way!
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