Timber decay and woodworm
Can old beetle holes in sapwood be historic rather than a live infestation?
Yes. Many softwood joists show old flight holes in the sapwood from beetles that attacked the timber years ago, sometimes before it was installed. If the timber is dry and firm and there is no fresh dust, the attack can be historic. A survey should not turn that into a treatment bill without saying why.
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?
The Property Care Association’s advice is to distinguish active attack from old damage and to deal with damp. A surveyor who writes “woodworm, possibly historic” is leaving that distinction open. Ask them what they would need to see to call it active. Fresh frass is the usual clue. A dead hole is not.
You can still repair a joist that has been weakened, even if the insects have gone. That is a structural judgement. Ask if any timber actually failed the prod of a screwdriver, where it was safe to prod. Replacement is a joiner’s quote. Spray is a different quote. Do not buy both by default.
What should you ask your surveyor?
- Which timbers looked historic, and which worried you as active?
- Did you see fresh dust?
- Is any timber structurally reduced, even if the insects have gone?
What are the typical next steps?
- Ask for the historic-versus-active point in writing if the report is ambiguous.
- Do not treat sound, dry sapwood as a project.
- If strength is the worry, ask a specialist or engineer about the section of timber, not about a spray.
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
Does every loft from the 1930s have woodworm?
No. Some do, some show old holes, some are clean. The year is not the inspection.
Will a mortgage lender refuse historic woodworm?
Ask the lender if the survey has worried them. Many will not care about old holes in sound timber. Do not invent a refusal.