What to do if your survey reveals woodworm

When you’re looking to buy a property, you will usually commission surveys to find out its condition and identify any issues. One of the findings that may be reported in the survey is an infestation of woodworm on the property.

The news that a property has woodworm can be cause for alarm. Woodworms can cause severe damage to furniture and timber in the property’s structure, which can be expensive to repair or replace.

If your survey shows that there are woodworm in the property, you might think that you should walk away from the purchase. However, there are ways to treat an active infestation, especially if it is caught early enough.

Woodworms can cause a lot of damage to the furniture and the structure of a house, so we’ve compiled this guide to help you treat the wood-boring insects and avoid future infestations.

What are woodworms?

Woodworm is the collective term used to describe the larvae of wood-boring beetles. These beetles lay their eggs in cracks or crevices in wood, and the resulting larvae burrow into the wood to feed and grow. This can cause significant damage to the wood over time, weakening it and compromising its structural integrity.

As adults, the grown beetles don’t eat and solely seek to reproduce. The wood-boring insects spend the large majority of their three to four-year life as larvae, where they burrow into wood. The grown beetles emerge in the summer season when they will try to reproduce and lay more eggs.

What are the types of woodworm

There are various types of woodworm that prefer different types of wood. The most common type of this insect is the Anobium Punctatum, otherwise known as the Common Furniture beetle. Other types include the House Longhorn beetle, the Deathwatch beetle and the Powderpost beetle.

Common Furniture beetle

The Common Furniture beetle is found in both soft and hardwood and leaves exit holes of around 2mm in diameter. They are found in both softwood and hardwood. This type of woodworm infestation is fairly easy to treat with insecticide spray.

Deathwatch beetle

Deathwatch beetles prefer Oak, Elm, Mahogany and other types of hardwood when they have been softened by fungal decay. This type of wood-boring insect is often found in old buildings and antique furniture and leaves holes of around 2 to 3mm in diameter. Deathwatch beetles are most commonly found in central and southern England.

This type of wood-boring insect makes a tapping or ticking noise to try and attract mates. They are the only type of woodworm that makes audible noise.

House Longhorn beetle

The most damaging wood-boring insect is the House Longhorn beetle, which is commonly found in the southeast of England. The beetle can grow up to 30mm long and can leave holes of up to 10mm in dry softwood. House Longhorn beetles prefer softwood such as pine, spruce and fir and often appear in roof timbers.

Powderpost beetle

These insects prefer hardwood saplings that are under ten years old. The holes they create are only around 1mm in diameter and are hard to spot. However, the beetles leave behind a flour-like substance, hence their name.

What are the signs of a woodworm infestation?

There are several signs you should look out for if you suspect you have woodworm. These include:

  • Fresh exit holes (usually found between May and October
  • Bore dust (frass) – this is a fine powdery substance usually found near exit holes
  • Tunnels in wood – these are left behind by larvae
  • Crumbling wood – the result of excess tunnelling and exit holes
  • Live or dead beetles – adult beetles may be looking to mate
  • Larvae – creamy-white coloured woodworm grubs

You may spot signs of woodworm, but they don’t necessarily indicate an active infestation. Dead beetles in an area that you don’t usually inspect, such as an attic or basement, could be a sign that the house previously had woodworm but doesn’t anymore.

Light-coloured wood showing within woodworm holes can indicate that the holes have been recently made. Fresh dust and sharp edges around the holes can also mean that they have been newly created and that there is an active woodworm population on the property.

Once you notice the first few signs of woodworm, you need to take action as quickly as possible. The damage will get worse the longer you leave treating the infestation.

Signs of woodworm infestation

What are the dangers of woodworm infestations?

Woodworm can cause severe damage to furniture and timber in buildings if left untreated. The larvae can bore deep into the timber structure, which can lead the wood to deteriorate and potentially collapse. The insects can also weaken floorboards enough that they collapse when someone steps on them.

The damage caused by woodworm won’t necessarily have a significant effect other than cosmetic damage to skirting boards and furniture, but it can be dangerous if the affected timber provides support to the building.

Severely affected timber may need to be removed and replaced. If left untreated, the damage could make the property unsafe for occupants and nearby structures, although this is only in extreme cases. It’s unlikely that the woodworm will spread to other furniture or areas of the house, but it is possible.

How can I treat a woodworm infestation?

Before you start trying to treat an infestation, you need to identify the affected areas and the type of beetle that has infested the wood. It’s a good idea to seek advice from a professional woodworm company if you aren’t sure how best to approach the infestation.

If you have Common Furniture beetles, you can treat them by using a permethrin-based woodworm treatment. This should help remove both larvae and grown beetles, as well as eggs left in the wood.

You should be able to find this in a spray or liquid form that can be painted with a brush. It’s a good idea to treat nearby furniture and wood with woodworm insecticide too, even if they don’t show signs of an infection. You should also avoid letting pets and animals in the room during and immediately after treatment.

Deathwatch beetles tend to burrow deep into the timber, which requires both surface treatment as well as injections into the wood. You could inject woodworm spray into the exit holes or drill into affected areas and fill the holes with treatment paste or gel.

It’s advisable to get professional woodworm treatment if you suspect you have a House Longhorn woodworm infestation. This type of larvae can cause extensive damage, so it needs to be dealt with properly. You can try to treat affected furniture using the same method that you would with Deathwatch beetles.

In some cases, it can be easier to get rid of the infected item of furniture if it doesn’t seem like the insects have spread elsewhere. If the furniture is already severely damaged, it’s unlikely that you would keep it even if the woodworm treatment proves successful.

How to prevent woodworm infestations

The best way to prevent a woodworm infestation is to make sure the wood is treated and varnished. Woodworms don’t tend to lay eggs in varnished and painted wood because they wouldn’t be able to find cracks and bore into the timber.

Warm and dry wood is unappealing to woodworm because the wood won’t be soft enough for them to chew through easily. Heated rooms tend to keep moisture levels low, which woodworms don’t like, as they need wood with moisture levels of at least 10%.

If you have wood left outside, you should try to keep it elevated and protected from moisture with a cover and potentially a waterproof varnish. Ideally, you should store wood in an outhouse, such as a shed, to keep it dry if you plan to bring it into your property.

Flytraps can help you catch and kill flying woodworm beetles in the summer. This will prevent them from spreading through your property and infesting multiple pieces of furniture and rooms. When you’re moving from one property to another, you should check your furniture for signs of woodworm infestation. You should treat or discard infected furniture so that the larvae and beetles don’t spread to other areas.

Where do woodworms come from?

Wood-boring insects generally prefer damp timber, although they can also infest dry wood. The grown beetles are capable of flying, which means they can come into properties through open windows or from infected furniture and blocks of wood.

The female beetles lay eggs in batches of between 30 to 60, which then hatch into larvae that tunnel through the wood. Eggs can’t survive on a painted surface, which is why female beetles seek out cracked wood to lay the eggs in. A female woodworm beetle will sometimes use old woodworm holes to lay their eggs in. However, the eggs will die if you have previously treated the holes with chemicals. The eggs also require a certain level of humidity to hatch, which is why female beetles look for poorly ventilated areas and infest damp timber.

Woodworm larvae usually live for three to four years before growing into beetles. Once fully grown, male beetles usually have less than a week to mate before they die, whereas female beetles can live up to two weeks before they die.

What attracts woodworm?

Woodworms thrive in damp, poorly-ventilated areas, especially in wood with wet rot. They usually target untreated, older furniture rather than new furniture that has been varnished. Pre-infected furniture is susceptible to future infestations because female woodworms are prone to laying their eggs in existing holes.

Different types of woodworm prefer different types of wood. Some types prefer softwood, and others prefer hardwood, but all variations like damp wood because it is easy to chew and burrow through. Female beetles look for wood with a moisture level of 28% or above because this gives their larvae the best feeding and growing into adults.

Woodworms are typically found in old buildings, such as churches, as well as sheds, attics and cellars. These areas are usually damp and have undisturbed sections.

Wooden dresser

Should I avoid buying a house with woodworm?

The level of damage that the woodworms have inflicted on the property should indicate whether you should continue with the purchase or not. If the damage looks old or minimal, it should be easily treatable. On the other hand, if the wood-boring insects are still active and have caused significant damage to the property’s structure, the cost of treating or replacing the infected areas could be expensive.

A woodworm specialist should be able to perform a home survey and tell you the type of beetle that has infected the property, as well as the best course of treatment.

And remember, you can always negotiate on the price following the results of any survey.


After a property survey, you may discover that there is an infestation of woodworm. This can be cause for concern if the wood-boring insects have infected multiple areas and already caused severe damage to the timber and furniture in the property.

You can treat woodworm using permethrin-based woodworm treatment. However, there are different techniques that you should use for different types of woodworm beetles. Common furniture beetles are fairly easy to treat with a spray or liquid treatment. Deathwatch beetles require a gel or paste to be injected into the exit holes, while House Longhorn infestations usually require specialist treatments.