How to treat woodworm

If you've noticed tiny holes in your wooden furniture or beams, you might be dealing with woodworm. These tiny creatures dig into timber and weaken it over time.

Find out how to identify these pests, recognise the key stages of infestation and uncover the best ways to treat them before they can cause lasting damage.

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What is woodworm?

A woodworm is, in fact, not a worm but the larvae of a wood-boring beetle. 

Woodworm can penetrate any wooden structure. They're particularly attracted to timber with a higher moisture content, as the moisture makes it easier for them to chew. So, if your property is prone to damp, there is a higher risk that you may get woodworm.

They have a relatively long life cycle for insects, and infestations can last up to several years. As most of the damage happens out of sight, it can be hard to realise you've got woodworm until a large amount of damage is done to the wood.

Adult female beetles access untreated wood through cracks and lay eggs inside. After about a fortnight, woodworm will hatch, eating through the wood to get to the surface. This process can take more than two years.

Once the worm is close to the surface, it pupates into an adult beetle, emerges, mates, and the cycle begins again.

Types of woodworm beetles

There are a few species of wood-boring beetles in the UK – each have variations in their life cycles and timber preferences.

• Common furniture beetle As the name suggests, these are the most common type found in homes and furniture. The larvae of these beetles can live in timber for three to five years before emerging to breed, and they consume hardwoods and softwoods. Grown beetles fly in warm, sunny weather.
• Deathwatch beetle This UK-native beetle is quite rare in the north and Scotland, found more often in southern and central England. Larvae can live between five and 10 years in wood before emerging, and adults measure 5-7mm in length with a dark red/brown colouring. These tend to infest hardwoods, such as seasoned oak, ash or sweet chestnut, and are more often found in older buildings.
• House longhorn beetle This beetle originates in Europe, but is now spread worldwide. In the UK, it's mainly found in the South East, particularly north west Surrey, giving it the nickname of the 'Camberley beetle'. Adults can reach 7-25mm in length, have a red/brown colouring with grey or white spots on each side. They also have long, curved antennae.
• Powder post beetle Like the deathwatch, this beetle infests hardwoods like oak, ash, elm, walnut and sycamore. Adults usually appear during the summer months, but they can be found all year round, and are a primary pest of timber yards. Fully grown, they measure 4-7mm in length, and are red/brown in colour.

In what months are woodworms active?

Woodworm season varies between species, though most tend to be active when the weather heats up.

They're typically active between March and October, when they emerge from timber, though species such as the house longhorn emerge between July and September, and the powder post beetle can be found throughout the year (though more frequently during the summer).

Signs of woodworm

The most obvious sign of woodworm affecting your property is visible holes, or ‘exit signs’ on timber, such as on loft beams or in floorboards. 

'Look for new bright holes in the timber with fresh tracks or piles of frass, which looks like sawdust,' says Phil Lund of Timberwise, a Which? Trusted Trader. 

'Holes will vary in size depending on the species of the wood borer, the most common being Anobium punctatum, or common furniture beetle, found in 75% of properties. The holes will be round, between 1-2mm in diameter. But for other wood borers it can be 15mm.'

Any timber that has been affected may also show visible damage and it might look similar to the damage caused by rot. See our guide to getting rid of damp for how to spot signs of rot.

Pests causing havoc in your home? See our guides to getting rid of clothes moths, flea beetles, bedbugs and mice

What does woodworm look like?

A woodworm larva is typically 2-7mm in length, though this can vary between species. Their bodies are creamy-white and worm-like, with a cylindrical or curved shape to them. They are rarely seen as they are very small and live within timber.

Woodworm treatment

If caught early enough, it’s possible to get rid of woodworm with a shop-bought treatment. 

‘Don’t panic,’ says Phil. ‘If you’re unsure of what you have, then seek advice from a professional. The majority of infestations can be treated successfully with very little disruption.

‘Take pictures of the holes and make a mental note of the number. You’re likely to see ongoing activity in the area you have treated as the treatment will not penetrate through the depth of the timber, but the beetle has to emerge to reproduce in most species and will come in contact with your treatment at that point. 

‘Monitor the areas adjacent to the treatments you’ve applied, and if you see new holes in other areas, then it’s time to call in the professionals.’

Key steps in identifying and treating woodworm are:

• identifying the species
• diagnosing if the infestation is active
• replacing the damaged timber.

A professional will be able to identify if you have an active infestation and the species of beetle that’s in your home, which will determine the best treatment to use to get rid of the infestation and prevent any further outbreaks.

Head to Which? Trusted Traders, or use the widget below to find a reliable professional in your area, endorsed by us.

Woodworm in furniture

If there’s woodworm in the timber in your property, it may well spread to your furniture. Items of furniture made of cherry, spruce, beech, birch and alder are particularly susceptible to woodworm, but don’t forget to check other types of wood, either.

The older your furniture is, the more likely there is to be woodworm – antique furniture, for example, can be especially appealing to woodworm.

The signs of woodworm in your furniture will be very similar to the signs in your home’s timber – small exit holes, evidence of frass and dead beetles around the suspected area.

How to treat woodworm in furniture

Unlike woodworm in a property’s timber, woodworm in furniture can be treated yourself. 

‘It’s not always easy to treat woodworm in furniture, particularly if it's hardwood,' says Nicholas Donnithorne of Peter Cox, a Which? Trusted Trader. 'Treat with an insecticide fluid and always follow the instructions.

’Some other tips that may help you treat an infestation in your furniture include removing the item to an area where there is no other wood, removing all varnish or finishes before applying insecticide and ensuring all wood is covered when applying the treatment.'

Depending on how bad the damage is, you may want to consider taking it to a restoration specialist, especially if the furniture is antique.

If it's time for some new furniture, or you're upcycling old pieces, head to our guide to the best furniture, homeware and DIY shops

How to prevent woodworm

Prevention is key, although this can be easier said than done. The main thing you can control is the humidity within your home.

‘Keep all timber dry,’ says Nicholas. ‘Woodworm generally prefers timber with a higher moisture level, so if timber gets damp, more damage is likely. By keeping your property well ventilated (and thus the timber within the property well ventilated), you’ll help to alleviate any further woodworm infestations.

‘Check timber and furniture before bringing it into the home,’ he adds. ‘Ply bases to drawers and the backs of wardrobes should always be checked for damage.’

Make sure you know how to spot and get rid of damp, as well as how to stop condensation. 

Wood-boring beetles find it difficult to lay their eggs inside treated woods. Varnished wood provides a hostile environment that woodworms do not like. They find it difficult to eat through this type of sealed wood.

Protect your garden and indoor timber with a wood preservative like Roxil Wood Preserver, available from Toolstation. Roxil’s biocidal component defends against woodworm infestation.

For wood already infested with woodworm, Soluguard Woodworm Treatment, also available from Toolstation, provides effective eradication of all stages of the wood-boring beetle lifecycle.

Keep condensation at bay with one of the best dehumidifiers