Small holes in timber are commonly called woodworm, but they record that an insect emerged at some point; they do not reveal when. Old houses can contain historic flight holes in otherwise serviceable timber. The key questions are whether activity appears current, whether timber strength has been affected and whether damp conditions continue to support decay.
A home survey examines accessible surfaces without cutting into the timber or identifying every insect species. Dust, insulation, paint and limited roof or floor access can obscure evidence. Where findings could affect structural safety or require extensive work, a specialist investigation may be recommended rather than an automatic treatment programme.
Evidence considered
Fresh bore dust, sharply defined holes, live insects and newly damaged surfaces may increase concern, but interpretation depends on species and season. Old dark holes with no fresh material may reflect historic activity. Surveyors also consider timber moisture, fungal decay, ventilation and the distribution of damage rather than counting holes alone.
Moisture and vulnerability
Several timber-boring insects favour damp or decaying timber. Roof leaks, blocked air bricks, ground moisture or poorly ventilated voids may therefore be more important than the visible holes. Addressing a moisture source can make conditions less favourable and prevent associated fungal decay.
Structural significance
Surface holes can look dramatic while leaving substantial sound timber; conversely, concealed internal damage may not be obvious. The element's role, remaining section and connections matter. A surveyor can identify possible weakening but a structural engineer or timber specialist may be needed where load-bearing capacity is uncertain.
Limits of a pre-purchase survey
Fixed ceilings, floors, wall linings and stored possessions are not removed. Insulation may conceal the upper faces of joists and the points where timbers enter walls. A one-time inspection may not capture seasonal insect activity. These limitations should inform the level of confidence in the report.
Proportionate action
Do not arrange blanket spraying merely because old holes exist. First establish whether activity is current, identify the organism where needed, assess structural condition and resolve excess moisture. Any treatment should be targeted, justified and compatible with the occupied building and historic fabric.
Ask a specialist to map the affected elements, record the evidence of activity and separate structural repair from pest control. The report should state inaccessible areas and whether follow-up inspection is needed in another season. In shared roofs or leasehold buildings, clarify responsibility and permissions before drilling, treating or replacing common structural timber. Ask how future activity will be distinguished from the old holes after work. Baseline photographs, retained samples and dated monitoring points can make later review more reliable.
- Keep samples or clear photographs of fresh bore dust
- Do not sweep away evidence before inspection
- Check roof and subfloor moisture sources
- Review treatment chemicals and occupancy precautions
Advice for your property
Get the right professional inspection
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Authoritative sources and further reading
The guide is general information, not property-specific, structural, legal, tax or financial advice. Source pages can change; consult the relevant professional for your circumstances.