Woodworm treatment and surveys

What a woodworm specialist does

Woodworm is the larval stage of wood-boring beetles. The common furniture beetle is the usual UK culprit. A specialist inspects the timber, works out whether the beetles are still active, names the species and checks the moisture in the wood. Only then do they recommend a treatment, or tell you none is needed.

Treatment is usually a spray or brush-on insecticide. Other options are injection, boron, heat treatment, or replacing badly damaged timber. After the survey there is normally one treatment visit. A return visit is only needed to inspect under a guarantee.

You will need to clear lofts, lift carpets and floorboards for access, and move furniture. Not sure you have woodworm at all? Read how to identify woodworm first.

What happens at a survey

The surveyor looks at the timber in the loft, under floors and around the building, probes it for soundness and measures moisture. You get a written report saying what they found, which timbers are affected and whether the beetles are active.

Ask for a survey fee that is credited against treatment, and for a report you can show a buyer or lender. If the verdict is inactive, you have paid for peace of mind and avoided a treatment you did not need.

Many woodworm holes are old

Holes alone do not mean you must pay for treatment. The Property Care Association (PCA) says an infestation may already have died out because the timber dried or was treated before. Unnecessary treatment wastes money.

Fresh holes have sharp, clean edges and fine pale dust below them. Old holes have dark, weathered edges and no dust. A simple check is to clear the dust in autumn and look again between June and August. The beetles emerge from May to September, peaking in June and July.

Ask for an independent survey that gives a clear verdict of active or inactive. Be wary of a free inspection from a firm that only earns money if it finds something to treat.

How the timber is treated

Damp timber drives woodworm, and low moisture content makes infestation unlikely. A good specialist deals with the cause as well: fix leaks, ventilate and let the wood dry. Beetles in treated timber die over the following season, though new emergence holes can keep appearing for up to a year. Replacing badly damaged joists or boards is separate structural work.

Guarantees commonly run 20 to 30 years with established firms. PCA members can offer insurance-backed guarantees, through QANW, that still honour the cover if the contractor stops trading. Ask for the guarantee in writing.

For prices, see woodworm treatment cost. If the area is small and easy to reach, the DIY guide explains what you can do yourself and what you should not.

Choosing a woodworm specialist

There is no woodworm licence. Treatment uses biocides under normal COSHH and product label rules, so anyone can offer it. Trade associations help you choose, but they run audits and codes of practice, not licences.

• PCA members are audited and their training is verified. The PCA runs surveyor qualifications such as CSTDB (Certificated Surveyor of Timber and Dampness in Buildings).
• CSRT (Certificated Surveyor in Remedial Treatment) is an older PCA title that many people still quote. Ask which qualification the surveyor holds, and for the certificate number.
• BPCA and NPTA members also treat woodworm.

Ask for a written survey report, a quote that names the timbers to be treated, and an insurance-backed guarantee.

Selling, mortgages and renting

A survey or guarantee matters when you sell. Lenders may impose a retention or ask for evidence of treatment. Sellers should disclose known treatment on the TA6 property form, and an old guarantee may pass to a buyer if its terms allow. Many flagged cases turn out to be old, which a survey can show.

For tenants, structural timber decay can be a hazard under the Housing Health and Safety Rating System if it affects safety, for example by risking structural collapse. In social housing, structural collapse is one of the hazards Awaab's Law adds from 30 November 2026. Private tenants can ask the council's private sector housing team to inspect.

Check for bats before any loft work

All bats and their roosts are protected, and treating a roof space without checking for bats can be an offence. If you have seen bats or droppings in the loft, tell the specialist before any work starts, and do not spray the timber yourself.

Do councils treat woodworm?

Councils do not treat woodworm, so you will need a private timber specialist, ideally a PCA member. See council pest control for the pests councils do treat.

Woodworm in floorboards

Small round holes in floorboards are common, and most are old. Look for fresh dust under the boards, or on the surface after you clear it, between June and August. If the boards feel solid when you press a screwdriver in and the hole edges are dark, the beetles have probably gone.

Floors are worth a proper look because joists sit below. Lift a board or two so a surveyor can check the joists and the moisture level. Call a specialist if you find fresh dust, soft timber or a bouncy floor, or if a buyer's lender has asked for a report.

Woodworm in the loft and roof

Roof timbers are where beetles often go unnoticed, so a survey before you buy or sell is common. Fresh dust on the felt or on ceilings below, and sharp-edged holes, suggest activity. Old, dark holes with no dust suggest it has finished.

Check for bats before anyone sprays. All bats and roosts are protected, and treating a roof space without checking can be an offence. Leaky roofing makes timber damp and attractive to beetles, so ask the specialist to look at the cause. Do not treat structural roof timber yourself.

Woodworm in the house

Holes in staircases, skirting, window frames or old furniture are usually from the furniture beetle. Spread across several rooms, they are worth a whole-house survey, which is often credited against the treatment if you go ahead.

A survey tells you which timber is affected and whether it is active, and whether damp is the underlying cause. Whole-house treatment is the dearest option, so confirm activity first. Ask the surveyor to mark the affected timbers on a plan, and keep the report for when you sell.