Selling a House with Woodworm: What You Need to Know

Woodworm is an umbrella term for the larvae of several species of wood-boring beetle that tunnel into timber as they feed, leaving characteristic exit holes when the adult beetles emerge. It is one of the most common timber problems in UK homes, and evidence of woodworm \u2014 whether active or historic \u2014 is routinely flagged in property surveys. For sellers, understanding what type of woodworm you are dealing with, whether it is still active, and how to handle it during the sale process can make the difference between a smooth transaction and one that stalls or collapses.

This guide covers everything UK sellers need to know about selling a property with woodworm, from identifying the species to managing disclosure, treatment, and buyer negotiations.

Types of woodworm found in UK properties

Not all woodworm is the same. The species of beetle determines the severity of the damage, the cost of treatment, and how concerned buyers and lenders are likely to be. The three most common species found in UK homes are outlined below.

Common furniture beetle (Anobium punctatum)

The common furniture beetle is by far the most prevalent wood-boring beetle in the UK and is responsible for the vast majority of woodworm damage in residential properties. The adult beetles are small (3\u20135mm) and brown, and the exit holes they leave in timber are round and approximately 1\u20132mm in diameter. The larvae feed on softwoods and the sapwood of some hardwoods, and they prefer timber with a moisture content above 18 per cent.

From a sale perspective, common furniture beetle is the least alarming type of woodworm. It is extremely widespread, treatment is well established and relatively affordable, and it rarely causes structural failure unless an infestation has been left untreated for many years. Most surveyors and mortgage lenders are familiar with it and will accept a professional treatment certificate and guarantee without requiring further action.

Deathwatch beetle (Xestobium rufovillosum)

The deathwatch beetle is a more serious concern. It primarily attacks hardwoods, particularly oak, and is most commonly found in older, historic buildings \u2014 often in structural timbers such as beams, joists, and roof trusses. The exit holes are larger than those of the common furniture beetle (approximately 3mm in diameter) and the bore dust is coarser, with visible pellets. Deathwatch beetle infestations are closely associated with damp conditions and prior fungal decay in the timber.

Because deathwatch beetle targets structural hardwoods and infestations often indicate underlying damp or decay issues, treatment can be more complex and expensive. Buyers and mortgage lenders may require a structural engineer\u2019s assessment in addition to a timber survey if deathwatch beetle is identified, particularly in period properties.

House longhorn beetle (Hylotrupes bajulus)

The house longhorn beetle is the most destructive of the three species but is relatively rare in the UK, largely confined to parts of Surrey and surrounding counties in South East England. It attacks softwood \u2014 particularly the sapwood of roof timbers \u2014 and the larvae can grow up to 30mm long, boring large oval exit holes (6\u201310mm) and causing significant structural damage. Under the Building Regulations (Approved Document to support Regulation 7), roof timbers in areas where house longhorn beetle is prevalent must be pre-treated with preservative.

If house longhorn beetle is found in a property, it is a serious matter. Structural timbers may need to be replaced entirely, and the cost of remediation can be substantial. Mortgage lenders will almost certainly require a full structural assessment and evidence that the infestation has been eradicated before lending on the property.

Active versus historic woodworm: why the distinction matters

One of the most important things to establish before you sell is whether your woodworm infestation is active or historic. The distinction has a significant impact on how buyers, surveyors, and mortgage lenders respond.

Many older properties in the UK show evidence of historic woodworm that is no longer active. The beetles may have died out naturally because conditions changed (for example, improved ventilation reduced timber moisture levels) or because the property was treated at some point in the past. If you have old exit holes but no fresh frass and no treatment records, a specialist timber survey can confirm whether the infestation is dormant.

How woodworm affects your sale

The impact of woodworm on your sale depends on the species involved, whether the infestation is active, the extent of the damage, and whether you have professional treatment records. Here is what to expect at each stage.

Impact on viewings and offers

Visible woodworm exit holes in floorboards, skirting boards, or furniture are noticeable during viewings and can concern buyers who are unfamiliar with how common the problem is. Being upfront about any known woodworm and having a treatment certificate or specialist report available demonstrates that you have dealt with the issue responsibly. Buyers who discover woodworm through their own survey without prior warning are more likely to renegotiate aggressively or withdraw.

Impact on surveys and mortgage valuations

Woodworm is one of the most frequently flagged issues in HomeBuyer Reports and Building Surveys. A general surveyor will note the presence of exit holes and typically recommend a specialist timber survey if there is any suspicion of an active infestation. The mortgage lender\u2019s valuation surveyor may also flag woodworm, which can lead to the lender imposing conditions such as requiring treatment before funds are released or applying a retention.

If the timber damage is severe \u2014 for example, if structural timbers have been significantly weakened \u2014 the surveyor may recommend a structural engineer\u2019s inspection, which adds time and cost to the transaction. This is one of the key reasons house sales fall through, particularly when the buyer is unprepared for the additional steps involved.

Estimated treatment costs by species

These figures are indicative and based on typical UK residential properties. Costs will vary depending on the size of the property, the accessibility of affected timbers, and regional labour rates.

Your disclosure obligations on the TA6

As a seller in England or Wales, you are required to complete the TA6 Property Information Form honestly. The form asks about known problems with the property, including timber defects and treatment history. You must disclose:

• Any current or historic woodworm infestation you are aware of, including the species if known.
• Any treatment that has been carried out, including dates, the contractor\u2019s name, and whether a guarantee was provided.
• Any structural timber repairs or replacements that were required as a result of woodworm damage.
• Any specialist reports or surveys relating to timber condition.

Failing to disclose known woodworm is misrepresentation. If the buyer discovers an infestation after completion that you knew about and concealed, they could pursue a legal claim against you. For a full overview of your obligations, see our guide on what to disclose when selling.

Getting a timber survey before you sell

Commissioning your own specialist timber survey before listing your property is one of the most effective steps you can take. A timber survey provides an accurate diagnosis of any woodworm, identifies whether the infestation is active or historic, assesses the extent of any structural damage, and recommends a course of action.

The Property Care Association (PCA) is the UK trade body for timber treatment and damp-proofing specialists. Using a PCA-accredited surveyor ensures the assessment meets recognised industry standards. A specialist timber survey typically costs between \u00a3150 and \u00a3400, depending on the size and type of property.

Having your own survey gives you several advantages:

• You know exactly what you are dealing with before marketing, so there are no surprises during the buyer\u2019s survey.
• You can arrange treatment proactively and obtain a transferable guarantee, which removes a major potential obstacle to the sale.
• If the survey confirms that the woodworm is historic and no treatment is needed, you have independent evidence to counteract any concerns raised by the buyer\u2019s general surveyor.
• You control the narrative rather than reacting to findings that may be presented in the worst possible light.

Treatment options and guarantees

Professional woodworm treatment in the UK typically involves applying a preservative spray or paste to affected timbers after any damaged or structurally compromised wood has been removed and replaced. The specific approach depends on the species, the severity of the infestation, and the type and accessibility of the affected timbers.

Chemical spray treatment

The most common treatment for common furniture beetle involves spraying a water-based insecticide (typically containing permethrin) onto the surface of affected timbers. This kills emerging adult beetles and any larvae close to the surface. It is the standard treatment for floor joists, floorboards, and roof timbers, and is effective against most common furniture beetle infestations. The treatment takes a few hours for a typical house and timbers can be walked on or used normally once dry.

Paste and gel treatments

For more targeted applications, particularly where timbers are partially embedded in walls or difficult to access with spray, paste or gel formulations can be applied directly to the timber surface. These are often used for deathwatch beetle in structural oak beams.

Structural timber replacement

Where woodworm damage has compromised the structural integrity of timbers \u2014 particularly with deathwatch beetle or house longhorn beetle \u2014 affected sections may need to be cut out and replaced. This work should be carried out by a qualified specialist and may require building control approval depending on the extent of the work.

Transferable guarantees

Treatment from a PCA-accredited contractor comes with a guarantee that typically runs for 20 to 30 years and transfers automatically to the new owner. This guarantee is one of the single most valuable documents you can provide when selling a property with a history of woodworm. It reassures the buyer that the work was done to a recognised standard and that recourse is available if the infestation returns.

If you have lost a treatment guarantee, contact the original contractor for a replacement. If that is not possible, your solicitor can arrange an indemnity insurance policy to cover the gap \u2014 a common and accepted solution in conveyancing.

Negotiation strategies for sellers

If woodworm is identified during the buyer\u2019s survey, some form of renegotiation after survey is likely. How you handle the negotiation can determine whether the sale proceeds at a fair price or collapses entirely.

Strategy 1: Treat before completion

Arranging professional treatment and providing a transferable guarantee before completion is often the cleanest solution. It removes the woodworm as an issue entirely, satisfies mortgage lender requirements, and demonstrates good faith to the buyer. The cost of treatment is typically less than the price reduction a buyer would demand, because buyers tend to overestimate remediation costs when negotiating.

Strategy 2: Agree a price reduction

If you prefer not to arrange treatment yourself, you can agree a price reduction based on the actual cost of professional treatment. Having your own quotes from PCA-accredited contractors puts you in a stronger position than relying on the buyer\u2019s estimates, which may be inflated. Provide two or three written quotes to demonstrate the genuine cost.

Strategy 3: Provide specialist evidence

If your timber survey confirms that the woodworm is historic and no treatment is needed, share this report with the buyer and their solicitor. A clear, independent specialist report can override the general surveyor\u2019s cautious recommendations and prevent unnecessary renegotiation. This is particularly effective when the general surveyor has flagged old exit holes without confirming whether the infestation is active.

How woodworm affects the conveyancing process

Woodworm creates additional work during conveyancing, particularly if it is flagged in the buyer\u2019s survey. Here is the typical sequence:

1. The buyer\u2019s survey flags woodworm. The surveyor notes exit holes, recommends a specialist timber survey, and may advise the buyer to obtain treatment quotes before proceeding.
2. Additional enquiries are raised. The buyer\u2019s solicitor sends enquiries to your solicitor asking about the history of woodworm, any treatment carried out, guarantees, and structural implications.
3. You provide documentation. Your solicitor shares any timber survey reports, treatment certificates, guarantees, and your responses to the enquiries. The more comprehensive your documentation, the faster this stage completes.
4. The buyer may renegotiate. Based on the survey findings and your responses, the buyer may seek a price reduction, request treatment before exchange, or in some cases withdraw from the sale.
5. Mortgage lender conditions. If the lender\u2019s valuer has flagged woodworm, the lender may require treatment, down-value the property, or impose a retention until treatment is confirmed.
6. Resolution and exchange. Once both sides agree on how the woodworm will be addressed \u2014 whether through treatment, a price adjustment, or a specialist report confirming no action is needed \u2014 the sale can proceed to exchange of contracts.

Pine helps sellers prepare for situations like this by guiding you through your property information forms before you list. By identifying potential timber-related disclosures early, your solicitor can prepare documentation and responses to likely enquiries in advance, rather than scrambling to respond after a buyer\u2019s survey raises concerns.

Preventing woodworm: what buyers want to know

Buyers who are aware of a woodworm history will often ask what has been done to prevent the problem from recurring. Woodworm beetles are attracted to damp timber, so the most effective long-term prevention is controlling moisture levels in sub-floor voids, roof spaces, and other areas where structural timbers are located.

• Ventilation. Adequate airflow beneath suspended timber floors and in roof spaces keeps timber moisture levels below the 18 per cent threshold that wood-boring beetles prefer. Ensure air bricks are not blocked and loft ventilation is unobstructed.
• Damp management. Address any sources of damp that could raise timber moisture levels, including leaking gutters, condensation, and rising damp. Woodworm and damp problems often go hand in hand.
• Timber treatment. Pre-treated timber is far more resistant to beetle attack. If timbers have been replaced as part of remediation, confirm that pre-treated timber was used.
• Regular inspection. Periodic checks of vulnerable timbers \u2014 particularly in roof spaces and sub-floor voids \u2014 allow early detection of any new activity.

Being able to demonstrate that you have taken steps to prevent recurrence reassures buyers and can help justify your asking price, particularly if you have invested in treatment.

Sources and further reading

• RICS (Royal Institution of Chartered Surveyors) \u2014 Surveying standards and guidance on timber assessment in residential properties: rics.org
• PCA (Property Care Association) \u2014 UK trade body for timber treatment and damp-proofing; find accredited contractors and surveyors: property-care.org
• BRE (Building Research Establishment) \u2014 Research and technical guidance on wood-boring insects in buildings, including identification and treatment: bregroup.com
• GOV.UK \u2014 Building regulations guidance for England, including requirements for timber preservation in areas affected by house longhorn beetle (Approved Document to support Regulation 7): gov.uk
• Historic England \u2014 Guidance on managing timber pests in historic buildings, including deathwatch beetle in listed properties: historicengland.org.uk

Related guides

• Selling a House with Wet Rot

Frequently asked questions