A woodworm infestation is beetle larvae feeding inside seasoned timber, sometimes for years, before emerging as adults through the holes that give the problem away. By the time the holes are visible the damage is done and the question is whether it is continuing. In most British houses the answer turns on how wet the timber is, because the beetles that matter here need a moisture content that dry, well ventilated wood does not reach.
Signs of woodworm, and what they mean
Round exit holes a couple of millimetres across, bore dust below them, and in a bad case timber that crumbles at an edge or a joist end that gives underfoot. Tunnelling runs along the grain and can hollow a member while the surface still looks sound, which is why a surveyor taps and probes rather than looking. Damage near a joist end or a wall plate matters far more than the same damage in the middle of a board.
Why it started
Almost always moisture. A slipped tile wetting a rafter, a bathroom extractor discharging into a cold loft, a blocked air brick under a suspended floor, or a failed damp course wetting a wall plate. Each of these creates a local patch of damp timber and the infestation follows the damp rather than the house. Finding that patch is the useful output of the survey.
What woodworm pest control treatment does
A surface or injected insecticide kills larvae near the surface and adults emerging through it. It does not reach deep tunnelling in thick sections, and it does not restore strength to timber that has already lost it. Where a member has been weakened the answer is structural repair or replacement, and a quote that offers spraying alone for a joist end that has gone is not addressing the real problem.
Active or historic: the question that decides everything
Most woodworm found in British houses is old and no longer active, and treating inactive damage is money spent on nothing. The signs of an active infestation are clean, sharp edged, light coloured holes rather than dark dusty ones, fresh bore dust the colour of the timber beneath the holes or on surfaces below, and live beetles in spring and early summer. Old holes are darkened, the edges are worn and there is no fresh dust. Sticking paper or tape over a patch of holes and checking it the following summer is a crude test that works: new holes through the paper mean live beetles emerging.
Why it is there, and what woodworm treatment near me quotes should cover
The common furniture beetle needs damp timber, so an active infestation is usually telling you about a moisture problem: a leaking gutter, a bridged damp proof course, an unventilated floor void or a wet loft. Fixing that is the treatment that lasts, and a chemical application without it is a holding action. A quote should separate the survey, the preparation such as lifting floorboards or clearing a loft, the treatment itself, any timber replacement where decay has weakened a joist end or a rafter, and the guarantee. Loft treatments are priced by area and access, and a loft full of stored belongings costs more because someone has to empty it.
Questions people ask about woodworm infestation
Is woodworm dangerous to the house?
It can be, where it has been active for a long time in structural timber. Most infestations found in British houses are historic and cosmetic. The distinction between the two is exactly what a survey exists to make, and it is not one that can be made from a photograph.
Do I have to leave the house during treatment?
Usually only for a stated period on the day, and the contractor should give you that in writing along with the product data sheet. If there are aquaria, birds or anyone with a respiratory condition in the house, say so before the work is scheduled.
Will the holes disappear after treatment?
No. Holes are permanent, and their presence afterwards does not mean the treatment failed. What should stop is fresh bore dust, which is why a competent contractor asks you to clear the dust and look again after a season.
How can I tell if woodworm is still active?
Fresh bore dust and clean, light coloured holes with sharp edges mean active. Dark, worn holes with no dust are historic. Covering an area with paper and checking the following summer for new exit holes settles it.
Do I need a woodworm specialist near me, or can I treat it myself?
Small localised furniture beetle activity in accessible timber can be treated competently by a householder. Structural timbers, roof timbers and anything where decay may have weakened a member want a survey, because the strength question matters more than the beetles.
How do I know if it is active woodworm?
Fresh bore dust that reappears after you clean it away is the clearest sign, along with holes whose edges are pale and sharp rather than grey and weathered. Emerging beetles in late spring and early summer are the other. Holes alone prove nothing, because they stay in the timber for the life of the building.