Death watch beetle infested log

What is a Deathwatch Beetle?

1 May 2019

The Deathwatch Beetle is one of a number of wood boring insects that are found in the UK, which are commonly classed as ‘Woodworm’.

The Deathwatch Beetle is chocolate brown in colour, and they grow to around 8mm in length. This makes the Deathwatch Beetle almost 3mm longer than the most common type of woodworm being found in the UK: The Common Furniture Beetle (Anobium Punctatum).

The Deathwatch Beetle has a variegated appearance as a result of having patches of ‘yellowish’ hairs, which means that the pattern on the Deathwatch Beetle’s back might vary from beetle to beetle due to these yellowish streaks.

In keeping with other varieties of woodworm, the Deathwatch Beetle emerges from timber during what is known as ‘the emergence period’, which tends to be from mid-March through to the end of June.

deathwatch beetle

Why Is It Called ‘The Deathwatch Beetle’?

The Deathwatch Beetle earned its name because of an old superstition. People performing a deathbed vigil, known as being ‘on watch’, would hear the clicking noise that the Deathwatch Beetle makes and believed that sound (and the beetle) to be an omen of death.

In reality, that clicking sound (which was believed to be made as the Deathwatch Beetle bumps its head against the tunnels in the timber it’s boring through) is actually a mating call, made by the beetle during the adult stage in their life cycle.

Timber showing signs of Deathwatch Beetle infestation

What Damage is Caused by The Deathwatch Beetle?


Death watch beetle infested timber

The main damage that a Deathwatch Beetle causes takes the form of extensive tunnelling within your property’s timber, which weakens the integrity of the wood and can lead to its degradation or total failure.

The damage caused by the Deathwatch Beetle looks very similar to that caused by the Common Furniture Beetle, although the exit holes from a Deathwatch Beetle are larger in appearance. This is to be expected as Deathwatch beetles are larger than the Common Furniture Beetle. The exit holes in the timber are approx. 3mm – 4mm in diameter, and are easy to spot even at a surface level.

Often around the exit hole, you will see the ‘frass’ deposited by the Deathwatch Beetle. Frass is the beetle’s excrement, with the Deathwatch Beetle’s frass appearing quite dark in colour, and shaped either like a disk, or a burger bun. The presence of frass is a tell tale sign of woodworm, and an indication of the kind of damage that the Deathwatch Beetle does to your property.

The Deathwatch beetle tends to almost always favour hardwoods, like Oak or Elm, and can be commonly found in these types of timber. However, the Deathwatch Beetle has also been known to infest softwoods like Cedar, or Pine, if they are suffering from rot and in contact with already infested hardwood. Often the timbers infested by the beetle show some signs of decay as a result of white rot (Donkioporia expanse), but be aware that the white-rot isn’t actually caused by the beetle.

Case Study: Deathwatch Beetle Affecting Converted Barn in Kent

Timberwise was contacted by the owners of a timber-framed converted barn in Ashford, to conduct a survey on the timbers within the property. Set in over an acre of stunning gardens and countryside, the property dates back to the 19th Century. The current owners were looking to modernise and convert the barn into a family home, without losing touch with the original features and history of the property.

The owners were concerned they had a woodworm infestation, because they had spotted several small, round holes in the timber, and fine powdery dust around said exit holes. This is a classic tell-tale sign of an infestation of woodworm, and they decided they needed expert help.

The Timberwise Surveyor inspecting the barn held the Certificated Surveyor of Timber & Dampness in Buildings (CSTDB) qualification, and upon inspecting the timbers, it became clear that the culprit of the visible damage was the Deathwatch beetle. The Deathwatch beetle infestation had affected all of the structural timbers within the barn, and if left without treatment the barn’s timber was seriously at risk.

In most cases, woodworm beetles can be treated with an insecticidal spray applied to the timbers. However, in this case, the damage caused by the deathwatch beetle was so severe that parts of the timber were treated with resin-based timber repairs and some parts needed replacing altogether with new timber.

Although discovering a woodworm infestation was not in the plans for the client’s large scale renovation project, with the customer’s patience and Timberwise’s expertise the Deatwatch Beetle in the barn was eradicated, and the property was transformed into a beautiful bespoke home.

How to Get Rid of The Deathwatch Beetle

Man treating timbers for woodworm

To get rid of a Deathwatch Beetle infestation it’s always best to call in the experts to evaluate the situation. A general woodworm survey must be carried out by a qualified timber specialist in order to ensure that the culprits are correctly identified.

Only through correct identification of the beetle can the right treatments be carried out. The surveyor will also inspect the property to identify the size of the infestation and the type of woodworm beetle.

The surveyor will also check to see at what stage of the lifecycle the wood boring insect is in – it may be that the damage is historic and therefore requires no further treatment.

The level of repairs needed will be assessed and a specification put together for any woodworm treatments deemed necessary to be carried out on the infected areas of timber.

For peace of mind, an assessment will be made to see if there are any other property care issues associated with infestation such as dry rot or damp.