Look for more than holes.
“Woodworm” describes damage from wood-boring insects rather than one single species. Flight holes may remain long after an insect has left, so they should be read with the timber’s moisture, softness, dust and surrounding conditions.
Fungal decay and insect attack can be connected to a damp building, but not every hole is active and not every soft timber problem is woodworm. The assessment should identify the likely pattern, its extent and whether the timber has a structural role.
Historic England explains how inadequate ventilation can increase moisture and allow wood-boring insects and fungi to damage older buildings. Its wider damp guidance is useful when the timber problem may be part of a building-moisture issue.
Historic England: understanding decay in an older home →
Historic England: assessing damp in historic buildings →
Dust and edges
Fresh bore dust and recently formed, sharp-edged holes may justify closer investigation, but are not conclusive alone. Dust can be moved or cleaned away.
Moisture and strength
Check moisture, softness, fungal decay, ventilation and whether the timber remains structurally sound. A structural concern needs the right specialist input.
Find the cause
Leaks, damp masonry, roof defects and poor subfloor airflow may be contributing to timber damage. Treating insects without reducing damp can leave the risk in place.
Before treatment, document the evidence.
- Photographs with a scale and location in the building
- Fresh dust, hole size, edges and whether signs return
- Timber moisture, softness, fungal growth and ventilation
- Leaks, damp masonry, roof defects or subfloor conditions
- Whether the timber is structural, decorative or inaccessible
Keep the written diagnosis, treatment specification, product details, treated areas and any monitoring recommendation with the property records.
Watch the building, not just the holes.
Follow the agreed inspection interval, keep ventilation and moisture sources under control, and record changes in dust, timber condition or surrounding damp. If the timber is structural, do not alter or load it differently without suitable advice.
Common questionsWoodworm in context.
Do old flight holes prove active woodworm?
No. Holes can be historic. A survey considers fresh bore dust, hole edges, timber condition, moisture, species and the wider building.
Why does moisture matter for woodworm?
Some wood-boring insects and fungal decay are associated with damp timber. Finding and reducing excess moisture can be as important as any treatment decision.
Does every timber floor need treatment?
No. Treatment depends on evidence, extent, timber condition and the structural role of the member. Some cases need monitoring, repair or structural advice instead.