Identification guide

UK Woodworm Species Guide

Six wood-boring beetles attack timber in British homes — but only some are a real threat. Identify yours by its exit holes and know exactly what to do next.

Compare exit-hole size, latin name and risk at a glance
Know which beetles are serious and which are harmless
Free survey to confirm the species before any treatment

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Why correct identification matters

"Woodworm" is not one insect. It is a catch-all name for the larvae of several wood-boring beetles, and they are not equally dangerous. Getting the species right is the single most important step, because it decides two things: how the timber should be treated, and whether you need to worry at all.

Roughly three quarters of UK infestations are the common furniture beetle, which is treated with a water-based surface spray and rarely threatens the structure of a house. At the other extreme, the death watch beetle works slowly through old oak and can hollow out structural timber over decades — needing deep boron treatment and sometimes repair. And a few beetles, such as the bark borer and the wood-boring weevil, are usually a sign of something else entirely rather than a problem in their own right.

The clearest first clue is the exit hole — the small opening an adult beetle chews on its way out of the wood. Size, shape and the type of timber narrow the field quickly. The cards below give you that at-a-glance comparison; tap through to any species for the full picture. When you are ready to be certain, a free woodworm survey confirms the species, whether the infestation is active or historic, and what treatment — if any — it needs.

Know your enemy

The six UK woodworm species

From the everyday furniture beetle to the rare house longhorn — here is each beetle, its tell-tale exit hole and how seriously to take it.

Common Furniture Beetle

Anobium punctatum

1–2mm

The UK's most common woodworm — responsible for roughly three quarters of all infestations in homes.

Risk: Moderate Identify →

Death Watch Beetle

Xestobium rufovillosum

3mm

A hardwood specialist found in old oak and historic buildings — slow, persistent and structurally serious.

Risk: High Identify →

House Longhorn Beetle

Hylotrupes bajulus

6–10mm (oval)

A rare but devastating softwood borer, concentrated in parts of Surrey and subject to specific building regulations.

Risk: Very high Identify →

Powderpost Beetle

Lyctus brunneus

1–2mm

Attacks the sapwood of hardwoods like oak and ash — often in newer flooring and recently imported timber.

Risk: Moderate Identify →

Wood-Boring Weevil

Euophryum confine

1mm (ragged)

A secondary pest of already-damp, decaying timber — its presence is a red flag for an underlying damp problem.

Risk: Low Identify →

Bark Borer Beetle

Ernobius mollis

1–2mm

Confined to bark and waney edges of softwood — frequently misidentified as furniture beetle and rarely needs treatment.

Risk: Low Identify →

Read the holes

Exit holes are your first clue

The hole an adult beetle leaves behind is roughly the diameter of the tunnel it grew in — so hole size maps closely to species. Crisp, pale-edged holes with fresh, gritty bore dust below them suggest the infestation is still active. Dark, dusty, weathered holes are often historic.

Use the rough guide on the right to point you in the right direction, then read the full profile for that beetle. For a complete walk-through of every sign — holes, frass, tunnels, weak timber and live beetles — see our signs of woodworm guide.

Hole size & shape	Likely species	Risk
1–2mm, round	Common furniture beetle	Moderate
3mm, round	Death watch beetle	High
6–10mm, oval	House longhorn beetle	Very high
1–2mm, round (hardwood)	Powderpost beetle	Moderate
~1mm, ragged	Wood-boring weevil	Low (damp flag)
1–2mm, in bark only	Bark borer	Low (harmless)

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Frequently asked questions

Why does it matter which woodworm species I have?

The species decides everything that follows. The common furniture beetle is treated with a straightforward surface spray, while the death watch beetle needs deep boron treatment and, often, structural repair. Some species — the bark borer and wood-boring weevil — barely need treatment at all. Identify the beetle correctly and you avoid both under-treating a serious problem and paying for work you do not need. A free woodworm survey settles it.

Can I identify woodworm myself from the exit holes?

Hole size and shape are a strong first clue — 1–2mm round holes point to the furniture beetle, 3mm holes to death watch, and 6–10mm oval holes to the rare house longhorn. But ragged holes, the type of timber and the colour of the bore dust all matter too, and several species overlap. Our signs of woodworm guide shows what to look for, but a surveyor confirms it for certain.

Which UK woodworm species is the most serious?

For most homes the common furniture beetle is the usual culprit and is very treatable. The death watch beetle and the house longhorn beetle are the ones that cause serious structural damage, though both are far less common and tend to be confined to older buildings or specific regions. Whatever the species, the same woodworm treatment process applies — survey first, then the right method for that beetle.

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