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Woodworm and timber decay: treat the cause, not just the beetle
Wood boring beetle needs damp timber. Get the moisture content of a floor or a roof below about twenty percent and you have removed the conditions the infestation depends on. That is why a blanket chemical treatment on a wet timber deals with this generation and leaves the conditions for the next, and why we survey the moisture before we survey the beetle.
What to look for
- Round flight holes, roughly one to two millimetres for common furniture beetle
- Fresh, gritty frass, the colour of clean sawdust, below or around the holes
- Holes with sharp, light coloured edges rather than dark, dusty ones
- Weakened or crumbling timber at joist ends, in floorboards and in roof timbers
- Beetles themselves, most visibly between May and August
Active or historic
This is the first and most valuable question, because it changes the cost by an order of magnitude, and it can usually be answered on site. Historic flight holes are dark, dusty and often painted over, with no fresh frass. Active infestation produces clean edged holes and gritty frass the colour of new sawdust, and it is found in timber that is damp enough to sustain it.
Most of the woodworm we are asked to look at in Kent and the South East is historic, in timber that dried out decades ago when the leak that caused it was repaired. Treating that achieves nothing beyond the invoice, and it is one of the more common overspecifications in this trade.
The species that matter
Common furniture beetle is the usual finding and the least serious, though it will weaken a floor if it is left in wet timber for long enough. Deathwatch beetle is a different matter: larger holes, associated with older hardwoods and typically with sustained damp and fungal decay in oak, and common in the timber framed and historic buildings across this region. It is slower, more destructive and needs the damp resolving as the first priority.
House longhorn beetle is rare nationally but taken seriously where it occurs because of the structural damage it causes to softwood roof timbers. Identifying which is present matters more than counting holes.
What we do about it
Establish the moisture content of the affected timber and find out why it is wet, which is usually a leak, a bridged wall, a blocked underfloor void or a defective gutter. Fix that and the infestation loses its conditions. Where structural timber has already lost section, it is replaced or reinforced, which is a carpentry job rather than a chemical one.
Where treatment is genuinely warranted, it is targeted at the affected timbers rather than sprayed through a whole house, and DampScan carries it out under an insured workmanship guarantee. A report that concludes the activity is historic and no treatment is required is a perfectly normal outcome and one we write frequently.
Find out whether it is active before you treat it
Moisture readings on the affected timber, identification of what is present, and a written report within 24 hours of the visit setting out what actually needs doing.
Book a surveyOr call 07386 225526.
Questions
Does the whole house need treating?
Very rarely. Blanket treatment of every timber in a property is one of the more common overspecifications we are asked to review. Beetle activity is confined to timber that is damp enough to support it, so it is normally localised: joist ends built into a wet external wall, floors above a poorly ventilated void, or roof timbers under a slow leak. Treating those and dealing with the moisture is both cheaper and more durable than treating everything.
How can you tell if woodworm is still active?
Mainly from the frass and the holes. Fresh frass is gritty and the colour of clean sawdust, and it accumulates below active holes; old frass is grey, compacted and often absent. Active holes have sharp, pale edges, while historic ones are dark and dusty and frequently painted over. Alongside that we take the moisture content of the timber, because activity requires damp wood. Dry timber with dark holes and no frass is a record of a problem, not a current one.
We found beetles in summer. Is that a bad sign?
It confirms activity, which is worth knowing, and it is not a reason to panic. Adults emerge to breed between roughly May and August, which is why infestations are noticed then. What matters is how much timber is affected, whether it has lost structural section, and above all why the timber is wet. Dealing with the moisture is what stops the cycle; the beetles are the symptom.