Spotting a scatter of tiny round holes in a floorboard, beam or old piece of furniture is enough to worry any homeowner. The good news is that woodworm is not always the emergency it first appears, and knowing what you are looking at makes all the difference. Here is how to tell what you have, whether it is still active, and what to do about it.
What actually is woodworm?
Despite the name, woodworm is not a worm. It is the larval stage of several species of wood-boring beetle. The adult beetle lays its eggs in timber, the larvae hatch and tunnel through the wood feeding on it for anything from two to five years, then emerge as adults through the small round holes you see on the surface. The most common culprit in UK homes is the common furniture beetle. Rarer but more serious species include the death watch beetle, usually found in old hardwood like oak in historic buildings, and the house longhorn beetle.
What are the signs of woodworm?
The tell-tale signs are:
- Small round exit holes in the timber, usually 1mm to 2mm across, with clean edges.
- Frass. A fine, powdery wood dust around or beneath the holes, left as the beetles emerge. It looks a little like sawdust.
- Crumbling or weak timber. If wood breaks away easily or feels soft, the tunnelling has weakened it structurally.
- Tunnels visible in cut or broken timber.
- Adult beetles, often found on windowsills near affected wood in late spring and summer when they emerge.
Woodworm tends to favour damp, poorly ventilated spots, which is why it often turns up in lofts, under floorboards and under stairs. Older and period properties, of which Lancashire has plenty, are more prone to it, particularly where there is any history of damp.
How do I know if the woodworm is active or old?
This is the most important question, because plenty of the holes people find are from an infestation that died out years ago and needs no treatment at all. Here is how to tell them apart. Active woodworm shows clean, sharp, light-coloured holes, often with fresh frass nearby. Old or historic woodworm shows darker, weathered holes with no fresh dust, and the timber around them is dry and stable.
A simple check: brush away any existing dust, mark a few of the holes with a pencil, and check back over the following weeks. Fresh frass or new holes appearing means the infestation is still active. Nothing new usually means it is historic.
Is woodworm serious?
It depends entirely on whether it is active and where it is. Many old infestations in furniture or non-structural timber are harmless and have long since stopped. Active woodworm in structural timber, however, such as floor joists, roof rafters and beams, is a different matter, because over time the tunnelling weakens the wood and can compromise the structure. The species matters too: the common furniture beetle is often of limited concern, whereas death watch and house longhorn beetle can cause serious structural damage. That is why correct identification, rather than panic, is the right first step.
Can I treat woodworm myself?
For a small, active infestation in a piece of furniture or an isolated timber, a shop-bought woodworm treatment based on permethrin, applied carefully to the affected wood, can do the job. What you should not do is treat timber that is not actually active, or assume a DIY spray has dealt with a problem deep in structural wood. Surface treatments do not always reach the larvae tunnelling well below the surface, and misjudging the extent of an infestation in joists or roof timbers is how small problems become expensive ones.
When should I call a professional?
If the woodworm is in structural timber, if it looks widespread, or if you simply cannot tell whether it is active, get a professional survey. A qualified specialist will identify the beetle species, confirm whether the infestation is live, check for the underlying damp that often drives it, and treat only what genuinely needs treating. That last point matters: a good firm will not sell you treatment for holes that have been dormant for decades.
Premier Environmental provides expert woodworm and timber treatment across Blackburn, Preston, Burnley and the surrounding areas. Book a survey and we will tell you honestly what you are dealing with.
FAQs
- Does woodworm mean my house has damp?
Often, yes. Wood-boring beetles are drawn to damp, poorly ventilated timber, so an active infestation frequently points to a moisture problem worth investigating alongside it. - Do I need to treat old woodworm holes?
Not if the infestation is inactive. Holes from a long-dead infestation are cosmetic and need no treatment. The key is confirming there is no fresh activity first. - When is woodworm most active?
Adult beetles emerge and are most visible in the warmer months, roughly April to October, which is the easiest time to spot fresh holes and frass.