Timber Treatment Guarantee for Sellers

If your home has ever had specialist treatment for woodworm, wet rot, or dry rot, the contractor who did the work should have issued you a timber treatment guarantee. This document becomes relevant the moment you put your property on the market, because the buyer's solicitor and surveyor will want to know about any past or current timber problems and what, if anything, was done to address them.

This guide explains what a timber treatment guarantee is, how it works, whether it transfers to the buyer, what to do if you cannot find yours, and how timber issues fit into the broader conveyancing process. For related guidance, see our guides on selling a house with woodworm and selling a house with wet rot.

What is a timber treatment guarantee?

A timber treatment guarantee is a written warranty issued by a specialist remedial treatment contractor following the successful eradication of a timber infestation or decay. It is not a government-issued document but rather a contractor's warranty, usually backed by an insurance-backed guarantee (IBG) scheme that continues to operate even if the contractor goes out of business.

The guarantee records:

• The property address
• The type of treatment carried out (for example, woodworm spray, wet rot fungicide and timber replacement, or dry rot eradication)
• The specific timbers and areas of the property that were treated
• The date of the work
• The duration of the guarantee (typically 20 to 30 years)
• The name of the issuing contractor and the insurance scheme backing the guarantee

The guarantee does not mean the timber will never develop problems again — it means that if the treated defect returns during the guarantee period due to the original treatment failing, the contractor (or their insurer) will carry out remedial work at no further cost.

Insurance-backed guarantees

Many timber treatment guarantees are backed by a specialist insurance scheme. This is an important distinction: a standalone contractor guarantee is only as good as the contractor that issued it, whereas an insurance-backed guarantee continues to have value even if the company closes. The Property Care Association (PCA), the main trade body for specialist remedial contractors in the UK, requires its members to provide insurance-backed guarantees on qualifying work. If your guarantee was issued by a PCA member, it should be backed by the PCA Guarantee Protection scheme, which is administered by Guarantee Protection Insurance (GPI).

The three types of timber treatment

Timber treatment guarantees are issued for three main categories of defect. Each involves different remediation methods and carries different implications when selling.

Woodworm treatment

Woodworm is the common name for the larvae of wood-boring beetles, most commonly the Common Furniture Beetle (Anobium punctatum). The larvae tunnel through timber for three to four years before emerging as adult beetles through distinctive 2–3mm flight holes. Woodworm is most commonly found in roof timbers and floorboards in older properties, though it can affect any structural or decorative timber.

Treatment involves applying a specialist insecticide solution to the affected timbers, either by spray or injection. The treatment kills active larvae and leaves a residual chemical barrier that prevents reinfestation. A standard woodworm treatment guarantee lasts 20 to 30 years. For more information on how woodworm affects a house sale, see our guide on selling a house with woodworm.

Wet rot treatment

Wet rot is timber decay caused by fungal attack of timber that has become consistently damp. The decay softens and discolours the wood, which may crumble when pressure is applied. Wet rot is localised — it cannot spread beyond the area of damp timber — which distinguishes it from the much more serious dry rot. Common locations include window frames, sill boards, doorsteps, and floor joists near external walls where moisture can penetrate.

Treatment involves removing severely decayed timber, treating surrounding wood with fungicide and preservative, and replacing structural sections with pre-treated timber or epoxy repair systems. A wet rot treatment guarantee typically covers the remediated area for 20 to 30 years, on the assumption that the source of moisture has also been addressed. For further guidance, see our guide on selling a house with wet rot.

Dry rot treatment

Dry rot (Serpula lacrymans) is the most serious of the three timber defects. Unlike wet rot, dry rot can spread through masonry and into areas of the building that are apparently dry, using strands (hyphae) to transport moisture to fuel its own growth. Left unchecked, it can destroy structural timbers across a large area of a building. Signs include white or grey fluffy mycelium, orange or rust-brown fruiting bodies (sporophores), a distinctive musty smell, and characteristic cuboid cracking of affected wood.

Dry rot treatment is the most invasive and expensive of the three, typically requiring removal of all affected timber (including a safety margin around the visible outbreak), treatment of masonry with biocide, and replacement of structural members with pre-treated timber. Dry rot treatment guarantees are usually 20 to 30 years from the date of works.

Are timber treatment guarantees transferable?

In most cases, yes. Timber treatment guarantees are generally transferable to the new owner of a property when it is sold, without any additional payment. The new owner inherits whatever remains of the original guarantee term. This is a significant benefit for buyers, because it means they are not simply relying on the seller's word that the treatment was effective — they have a continuing warranty.

However, the mechanics of transfer vary between contractors and guarantee schemes. Some guarantees transfer automatically on change of ownership. Others require the new owner to formally notify the contractor or the insurance scheme within a specified period after completion. It is worth checking the terms of your specific guarantee document for any notification requirements, and ensuring that the completion is communicated to the relevant party once the sale completes.

Guarantees issued under the PCA Guarantee Protection scheme are transferable as a matter of course. If the original contractor has ceased trading, the guarantee continues to be administered by the insurance scheme, and the new owner can make claims directly to the insurer if the treated defect recurs.

What if the guarantee has expired?

An expired timber treatment guarantee is not necessarily a problem in a property sale. The treatment itself does not expire with the guarantee — a properly applied woodworm treatment, for example, leaves a residual insecticide in the timber that remains effective for much longer than the guarantee period. What expires is the warranty protection, not the effectiveness of the treatment.

Whether an expired guarantee causes difficulty in a sale depends on the buyer and their solicitor. Many will simply note that the guarantee has expired and proceed, particularly if the survey shows no active signs of infestation. Others may request a new inspection or a price adjustment. In most cases, an expired guarantee on documented, professional treatment is far preferable to having no record of treatment at all.

Disclosing timber treatment on the TA6 form

The TA6 Property Information Form is the key disclosure document in English and Welsh residential conveyancing. Section 7 of the TA6 asks directly about specialist treatments, including whether any timber or damp treatment has been carried out, and if so, whether guarantees were provided.

You must answer these questions honestly and completely. The legal basis for this obligation is the law of misrepresentation: if you knowingly provide false or misleading information in the TA6 and the buyer later discovers this and suffers financial loss as a result, they may have grounds to claim damages against you or, in serious cases, to rescind the contract.

Practically speaking, you should disclose:

• The type of timber treatment carried out (woodworm, wet rot, dry rot)
• The approximate date the work was done
• The name of the contractor, if known
• Whether a guarantee was issued and its duration
• Whether you hold a copy of the guarantee, or if it has been lost

If you are unsure whether historic treatment was carried out, look for signs such as injection holes in skirting boards or floor joists (indicating past damp or woodworm treatment), areas of replastered wall at low level, or references to treatment in your conveyancing documents from when you bought the property. If you bought the property with a timber treatment guarantee, it should have been included in your solicitor's file.

What to do if you cannot find your timber treatment guarantee

Losing a timber treatment guarantee is a common problem. The document may have been misfiled, left behind during a previous move, or simply never passed on to you by your own solicitor when you purchased. Here is the sequence of steps to follow:

1. Contact the original contractor. If you know which company carried out the treatment, contact them directly and ask for a duplicate certificate. Reputable contractors and PCA members keep treatment records and can usually reissue a certificate for a small administration fee or free of charge.
2. Search the PCA Guarantee Protection database. The Property Care Association maintains records of guarantees issued by its members. You can search the database by property address at property-care.org or contact the PCA directly. If the guarantee is registered, a replacement can be issued.
3. Check your solicitor's file from your purchase. When you bought the property, the timber treatment guarantee should have been included in the documents your solicitor received from the seller's solicitors. Your solicitor is required to retain conveyancing files for at least six years. Contact them and ask for a copy.
4. Search other paperwork. Check any home information pack materials, previous surveyor's reports, and correspondence between solicitors. Guarantees are sometimes included as attachments to other documents.
5. Consider indemnity insurance. If none of the above steps produce a result, your solicitor can arrange indemnity insurance to cover the risk associated with the missing guarantee. This should be done—and can only be done—before any formal enquiry is made with the contractor or the PCA, because the insurer will not provide cover once the absence of the guarantee has been formally flagged.

Indemnity insurance for missing timber treatment guarantees

Indemnity insurance is frequently used in conveyancing to resolve situations where documentation is missing. A missing timber treatment guarantee is one of the most common scenarios. The policy covers the buyer and their mortgage lender against the financial cost of remedial work if the treated defect recurs and the original guarantee cannot be relied upon because it cannot be located.

Key points to understand about indemnity insurance in this context:

The critical limitation is important. Indemnity insurance for a missing guarantee can only be arranged if the absence has not yet been formally investigated or disclosed to the contractor. Once you contact the contractor and they confirm on record that no guarantee was issued or that it cannot be reissued, the insurer will decline to cover the risk. Your solicitor will advise you on the correct sequence of steps.

It is also important to understand what indemnity insurance does not cover. It covers the risk arising from missing documentation — it does not cover an existing, active timber problem. If the buyer's survey identifies live woodworm, active wet rot, or signs of dry rot, indemnity insurance will not be sufficient. The problem will need to be professionally treated before the sale can proceed.

For context on how indemnity insurance is used more broadly in property transactions, see our guide on what is a property certificate pack.

How timber treatment fits into conveyancing

Timber treatment guarantees typically surface at one or more points during the conveyancing process:

The TA6 Property Information Form

As described above, the TA6 asks directly about specialist treatments. The answers you provide here set the agenda for enquiries that the buyer's solicitor will raise. If you disclose timber treatment and provide the guarantee, the enquiry is usually resolved quickly. If you disclose treatment but cannot provide a guarantee, the buyer's solicitor will follow up to understand why and may request indemnity insurance.

The buyer's survey

Even if you have not disclosed any timber treatment, the buyer's surveyor may identify signs of past treatment (such as injection holes in skirting boards, replaced floorboards, or new plaster patches on external walls at low level) or signs of current timber defects. If the surveyor recommends a specialist timber inspection, the buyer is likely to commission one, and the outcome of that inspection will influence how the transaction proceeds.

Pre-contract enquiries

The buyer's solicitor may raise specific enquiries about timber treatment as part of the standard conveyancing enquiries. They may ask for copies of guarantees, details of the treatment carried out, and confirmation of whether the guarantee is transferable. Providing complete and accurate answers to these enquiries promptly is one of the most effective ways to keep a sale moving.

Mortgage lender requirements

If the buyer is purchasing with a mortgage and the survey or enquiries flag a timber issue, the lender may impose a retention on the mortgage (withholding a portion of the loan until the issue is resolved) or require evidence of treatment before releasing funds. This can create a gap in the buyer's finances that needs to be bridged, which is a common cause of delays and sometimes collapsed transactions.

Getting treatment done before you sell

If you know your property has a timber problem that has not yet been treated, there are clear advantages to addressing it before marketing:

• You control the choice of contractor and can obtain competitive quotations
• You receive a guarantee that can be passed on to the buyer, which is a positive selling point
• You avoid the risk of the buyer's survey flagging the problem and triggering a price renegotiation or mortgage retention
• The sale is less likely to be delayed by further investigations or remediation requirements

If you decide to sell with a known timber problem untreated, you must disclose it on the TA6 form. In this case, obtaining quotations for the work before marketing is still sensible, because it allows you to inform potential buyers of the likely cost and to price the property accordingly. Buyers are generally more comfortable with known issues that have a clear and costed solution than with problems where the extent and cost are uncertain.

When obtaining quotations for timber treatment, use contractors who are members of the Property Care Association (PCA), as their work standards, guarantee terms, and insurance backing are more consistent and more likely to be accepted by buyers and their solicitors. For more context on the costs involved when preparing a property for sale, see our guide on the hidden costs of selling a house.

What buyers and their solicitors expect

When a buyer's solicitor learns that timber treatment has been carried out, they will typically want to see:

1. The original timber treatment guarantee or a certified copy
2. Confirmation that the guarantee is transferable to the new owner
3. Confirmation that the guarantee is insurance-backed (if applicable)
4. Details of any conditions on the guarantee (for example, maintenance obligations or limitations on the scope of cover)

If any of these items are missing, the buyer's solicitor will raise an enquiry asking for them or for an explanation of why they cannot be provided. The most common acceptable alternatives are a replacement certificate from the original contractor or the PCA, or an indemnity insurance policy arranged before the enquiry is raised.

Buyers and their surveyors are increasingly knowledgeable about timber defects, particularly in older properties. A properly documented treatment with a transferable guarantee is generally viewed positively, because it demonstrates that a problem was identified and professionally resolved. This is a better position to be in than a property where timber issues are suspected but no action has been taken.

Timber treatment and building regulations

Routine timber treatment (woodworm spray, wet rot fungicide, or dry rot eradication) does not in itself require Building Regulations approval. However, if the treatment involves replacing structural timbers — such as roof rafters, floor joists, or structural beams — then the structural replacement work may fall within the scope of Building Regulations. In practice, a reputable contractor will advise you on whether a Building Regulations application is needed for structural replacement work as part of the remediation.

If structural timbers were replaced as part of a dry rot treatment and no Building Regulations sign-off was obtained, this may be flagged by the buyer's solicitor. For guidance on what to do in this situation, see our guide on missing Building Regulations sign-off.

Costs at a glance

Practical checklist for sellers

1. Search your property documents for any timber treatment guarantee. Check your solicitor's conveyancing file from your purchase if you cannot find it elsewhere.
2. If you have the guarantee, confirm it is transferable and check whether you need to notify the contractor or guarantee scheme when the sale completes.
3. Inspect accessible timber areas — the loft, under floors where possible, and around windows and external doors — for signs of active infestation or decay. If you find any, commission a specialist survey before marketing.
4. Complete the TA6 form honestly, disclosing all timber treatment and guarantee details.
5. If the guarantee is lost and there are no active timber problems, discuss indemnity insurance with your solicitor as a quick solution. Do this before making any formal enquiry with the contractor.
6. If you know treatment is needed but has not been done, obtain quotations from PCA members before marketing, and consider whether to carry out the work first or price the property to reflect the cost.

Sources

• Property Care Association (PCA) — property-care.org
• PCA Guarantee Protection Insurance — Guarantee Protection Insurance Ltd (GPI) — guaranteeprotection.co.uk
• Royal Institution of Chartered Surveyors (RICS) — rics.org
• Building Research Establishment (BRE) — Information Paper IP 12/85: Dry rot and wet rot — bregroup.com
• Law Society — TA6 Property Information Form, 5th edition, 2020
• Building Regulations 2010 (as amended) — legislation.gov.uk
• Misrepresentation Act 1967 — legislation.gov.uk

Related guides

• Damp Proof Course Guarantee: What Sellers Need

Frequently asked questions