Timber decay and woodworm
There are furniture-beetle holes in the loft rafters and more holes in the staircase. Are the stair strings a structural problem?
Only if the strings themselves are attacked in the sapwood that is doing the work, and the survey could see that. Holes in loft rafters are a roof-timber comment, while holes in a painted tread are not automatically the same attack on the strings. A home survey often cannot see the hidden face of a string, and flight holes alone do not date the insects.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
Common furniture beetle leaves small flight holes, often in sapwood. The Property Care Association treats insect damage together with the question of whether the timber is still doing its job and whether it is damp. Rafters in a loft and stair strings in a hall are different pieces of wood in different conditions. The strings carry the stair. Soft sapwood edges on a string matter more than old holes in a decorative tread or in a piece of non-structural trim. The surveyor should say which timber they examined and whether the wood was still firm.
Do not buy one spray for “the beetles in the house” from a mix of loft holes and stair holes. Ask if fresh bore dust was present in each place, or only dark old holes. Ask whether the strings were visible on their underside and their wall edge. If carpet, paint and plaster hide them, say the strings were not assessed. A loft treatment certificate does not cover a stair it never mentioned. If the strings are soft, that is a stair repair, specified by someone who has seen them, not a fogging of the cupboard.
What should you ask your surveyor?
- Which stair timbers did you see, and were the strings among them?
- Were the holes in the loft accompanied by fresh dust, and was the stair the same or different?
- Are you saying the strings are structurally affected, or that you could not see them?
What are the typical next steps?
- Keep the loft and the staircase as separate notes to any timber firm.
- Do not sand or strip the stair to hunt for holes before you own it.
- If the strings were hidden, do not pay for a structural stair repair the survey did not describe.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
Are all flight holes in a stair the strings?
No. Treads, risers and trims are not the strings. Ask which piece of wood has the holes.
Does beetle attack in the loft spread down the walls to the stair?
The survey cannot say the insects walked the house. Each timber is judged where it was seen.