Damp Proof Certificate When Selling: Do You Need One?

Damp is one of the most common issues raised during property transactions in England and Wales. Whether it appears in the buyer's survey, comes up in conveyancing enquiries, or is flagged by the mortgage lender's valuer, evidence of damp — past or present — will need to be addressed before the sale can complete.

If your property has had damp proofing work carried out at any point, the buyer's solicitor will almost certainly ask for the damp proof certificate and its associated guarantee. This guide explains what a damp proof certificate is, when you need one, what to do if you cannot find it, and how indemnity insurance can sometimes provide a pragmatic solution.

What is a damp proof certificate?

A damp proof certificate is a document issued by a specialist contractor after installing, repairing, or replacing a damp proof course (DPC) in a property. A DPC is a physical or chemical barrier built into the walls of a building, typically at or near ground level, to prevent moisture from the ground rising up through the masonry. Most properties built after 1875 have a DPC, as the Public Health Act of that year made them a requirement in new buildings.

The certificate serves as proof that the work was carried out to a professional standard and is normally accompanied by a guarantee lasting 20 to 30 years. In many cases, the guarantee is backed by an insurance-backed guarantee (IBG) scheme, which means the cover continues even if the original contractor goes out of business. The Property Care Association (PCA), the leading trade body for damp proofing contractors in the UK, requires its members to provide insurance-backed guarantees on all qualifying work.

The certificate typically records the date of treatment, the type of damp proof course installed (for example, a silicone injection DPC or a physical membrane), the areas of the property treated, and the duration of the guarantee. It is an important document during a property sale because it reassures the buyer and their mortgage lender that a known damp issue has been professionally resolved.

The three types of damp and how they affect a sale

Before considering whether you need a damp proof certificate, it is helpful to understand the three main types of damp that affect UK properties. Each has different causes, different remedies, and different implications for your sale.

Rising damp

Rising damp occurs when groundwater is drawn upward through porous masonry by capillary action. It typically affects the lower sections of walls, leaving characteristic tide marks up to about one metre above floor level. Signs include salt deposits (efflorescence), peeling wallpaper, and deteriorating plaster. Rising damp is the type most commonly associated with damp proof certificates, because the standard remedy is to install or replace the DPC.

According to the Building Research Establishment (BRE), genuine rising damp is less common than many people assume. A significant proportion of cases diagnosed as rising damp are actually caused by other moisture sources, such as bridged DPCs, high external ground levels, or defective sub-floor ventilation. This is one reason why a report from a qualified, independent surveyor — rather than a contractor offering a free survey — carries more weight with buyers and their solicitors.

Penetrating damp

Penetrating damp is caused by water entering through the external fabric of the building. Common causes include cracked or missing pointing, defective render, leaking gutters and downpipes, damaged roof tiles, and poorly sealed window and door frames. Unlike rising damp, penetrating damp can appear at any height on a wall and is often linked to specific defects that can be repaired without installing a new DPC.

A damp proof certificate is not relevant to penetrating damp. Instead, the buyer will want evidence that the source of water ingress has been identified and repaired. If penetrating damp is found during a survey, the buyer's solicitor may ask for evidence of remedial work or request a retention from the purchase price to cover the cost of repairs.

Condensation

Condensation is by far the most common form of damp in UK homes. It occurs when warm, moist air meets cold surfaces — typically windows, external walls, and areas with poor ventilation. It leads to mould growth, particularly in bathrooms, kitchens, and bedrooms. Condensation is a lifestyle and ventilation issue rather than a structural defect, and it does not require a damp proof certificate.

While condensation rarely derails a sale on its own, visible mould can concern buyers and may be flagged in a survey. Improving ventilation, using extractor fans, and treating visible mould before viewings is sensible preparation. For more on preparing your property, see our guide on damp and selling a house.

Do you need a damp proof certificate to sell?

There is no legal requirement to provide a damp proof certificate when selling a property in England and Wales. It is not one of the documents needed to sell a house in the same way that an EPC or title deeds are. However, whether you need one in practice depends on the circumstances of your sale.

You will almost certainly be asked for a damp proof certificate if:

• The buyer's surveyor identifies signs of past damp treatment, such as injection holes at the base of external walls or replastered areas with a salt-inhibiting render.
• You have disclosed damp treatment on the TA6 Property Information Form (which you are obliged to do if you are aware of it).
• The property's title deeds or previous conveyancing files reference damp proofing work.
• The mortgage lender's valuer flags damp as a concern and asks for evidence of remediation.

If none of these apply — for example, if the property has never had damp treatment and no damp is identified during the survey — then a damp proof certificate is not needed and the issue is unlikely to arise.

DPC guarantees: what they cover and how they transfer

When a damp proof course is installed, the contractor typically provides a guarantee covering the workmanship and materials for a fixed period. Understanding how these guarantees work is important when selling, because the buyer will want to know whether the protection transfers to them.

Duration and coverage

Most DPC guarantees last 20 to 30 years, though some PCA members offer guarantees of up to 40 years. The guarantee covers the failure of the damp proof course itself — for example, if the injected silicone barrier breaks down and rising damp returns. It does not usually cover damp caused by other factors, such as raised external ground levels, blocked sub-floor ventilation, or plumbing leaks.

Transferability

DPC guarantees are generally transferable to subsequent owners of the property without additional cost. This means that if your guarantee has 15 years remaining when you sell, the buyer inherits that 15 years of cover. Some guarantees require notification to the issuing company when the property changes hands, so check the terms of your certificate and inform the contractor or guarantee provider when the sale completes.

Insurance-backed guarantees

An insurance-backed guarantee (IBG) provides an additional layer of protection. If the original contractor ceases trading, the insurance company steps in to honour the guarantee. The PCA requires its members to provide IBGs on all qualifying damp proofing work. When selling, an IBG gives the buyer considerably more confidence than a standalone contractor guarantee, because it removes the risk of the guarantee becoming worthless if the company folds.

What to do if you have lost your damp proof certificate

Losing a damp proof certificate is a common problem, particularly for sellers who have owned their property for many years or who did not receive the certificate when they purchased. Here are the steps to take:

1. Contact the original contractor. If you know which company carried out the damp proofing, contact them directly. Most contractors keep records and can issue a replacement certificate. If the company has changed name or been acquired, try searching Companies House for the current trading entity.
2. Check the PCA guarantee database. The Property Care Association maintains a register of guarantees issued by its members. If the original contractor was a PCA member, the guarantee should be on their database and you can request a replacement. Contact the PCA directly or search through their website.
3. Check your conveyancing file. If the damp proofing was done before you bought the property, the certificate should have been included in the conveyancing documents you received when you purchased. Contact the solicitor who acted for you on that purchase, as they may still hold the file. Law firms are required to retain conveyancing files for at least six years, and many keep them for longer.
4. Ask your mortgage lender. If your mortgage lender required a damp proof certificate as a condition of the original mortgage, they may hold a copy on file.
5. Search property documents. Check any paperwork you received when you bought the property, including the home information pack (if applicable), the surveyor's report, and any correspondence between solicitors.

If none of these steps produce the certificate, you have two remaining options: commission a new damp survey or arrange indemnity insurance.

Commissioning a new damp survey

If you cannot locate the original certificate and the buyer or their lender requires evidence of the damp situation, commissioning a new damp survey is one option. A specialist damp surveyor will inspect the property, test moisture levels in the walls using a calibrated moisture meter (and sometimes a carbide test for more accurate readings), and provide a written report on the current condition.

Costs

A specialist damp survey typically costs between £150 and £500, depending on the size of the property and the extent of investigation needed. For a standard two- or three-bedroom house, expect to pay £200 to £350. Choose a surveyor who is a member of the PCA or RICS (Royal Institution of Chartered Surveyors), as their reports are more credible to buyers and lenders.

What the report will show

A good damp survey report will confirm whether rising damp is present, whether a functioning DPC exists, and whether any remedial work is needed. If the surveyor finds that the property is dry and the existing damp proofing is effective, the report effectively serves as a substitute for the original certificate and should satisfy the buyer's solicitor and mortgage lender.

If the survey reveals that the damp proofing has failed or that new damp issues have developed, you will need to decide whether to carry out the remedial work before selling or negotiate a price adjustment with the buyer. For more on how damp findings affect a sale, see our guide on damp and selling a house.

Indemnity insurance as an alternative

Indemnity insurance is frequently used in conveyancing to cover risks where documentation is missing. A missing damp proof certificate is one of the most common scenarios where indemnity insurance is arranged.

How it works

The policy covers the buyer (and their mortgage lender) against the financial cost of remedial work if the damp proofing fails and the original guarantee cannot be relied upon because the certificate is missing. The policy is taken out at the point of sale and lasts indefinitely, transferring automatically to future owners of the property.

Cost

Indemnity insurance for a missing damp proof certificate is relatively inexpensive. A one-off premium of £30 to £100 is typical, depending on the value of the property and the level of cover. There are no ongoing payments. The seller usually pays for the policy, though this is negotiable.

When indemnity insurance is accepted

Most buyers and mortgage lenders will accept indemnity insurance in place of a missing damp proof certificate, provided there are no current signs of damp in the property. If the buyer's survey has identified active damp, indemnity insurance is unlikely to be sufficient — the insurer will not provide cover for a known, existing problem. In that case, the damp will need to be investigated and remediated before the sale can proceed.

Important limitation

Indemnity insurance must be arranged before any investigations or enquiries are made with the original contractor or the PCA. This is because insurers will not cover a risk that has already been escalated or where the absence of the certificate has been formally confirmed. Your solicitor will advise you on the correct sequence of steps to keep the insurance option open.

Disclosing damp treatment on the TA6 form

The TA6 Property Information Form asks specific questions about alterations and works carried out on the property, including any damp treatment. You are legally required to answer these questions honestly. The relevant sections require you to confirm whether any damp proofing, timber treatment, or other remedial work has been done, and if so, whether guarantees were provided.

If damp treatment has been carried out, you should:

• Confirm the date the work was done, or approximate date if you are unsure of the exact one
• State the name of the contractor who carried out the work
• Confirm whether a guarantee was issued and its duration
• Provide the certificate if you have it, or explain that it has been lost and what steps you have taken to locate it

If you are aware of any current damp issues, you must disclose these too. Deliberately concealing known damp problems is a form of misrepresentation that could expose you to a legal claim from the buyer after completion. If in doubt, disclose it — your solicitor can help you frame the disclosure appropriately.

What happens when the buyer's surveyor finds damp

Damp is one of the most common findings in RICS HomeBuyer Reports and Building Surveys. If the buyer's surveyor identifies signs of damp, several things may happen:

1. Request for the damp proof certificate. The buyer's solicitor will raise an enquiry asking for the DPC certificate and guarantee. If you have it, provide it promptly. If not, follow the steps above.
2. Request for a specialist survey. The surveyor may recommend that a specialist damp survey is carried out. The cost of this is usually borne by the buyer, though the seller may commission one pre-emptively to keep control of the process.
3. Price renegotiation. If the survey reveals damp that requires remedial work, the buyer may request a reduction in the purchase price to reflect the cost of repairs. This is a negotiation — you are not obliged to agree, but refusing may cause the buyer to withdraw.
4. Mortgage retention. The lender may impose a retention on the mortgage, withholding a portion of the loan until the damp issue is resolved. This can cause complications at completion if the buyer does not have the funds to bridge the gap.
5. Withdrawal. In serious cases — particularly where there is structural damage from prolonged damp or the cost of remediation is uncertain — the buyer may withdraw from the purchase entirely.

When damp becomes a deal-breaker

Not all damp issues are equal. Minor condensation or a historic damp treatment with a valid guarantee are unlikely to cause problems. However, damp can become a deal-breaker in several scenarios:

• Severe rising damp requiring a full DPC. Installing a new chemical injection DPC with associated replastering can cost £3,000 to £8,000 or more depending on the extent of the affected area. Buyers may not want to take on this cost or the disruption involved.
• Structural damage from prolonged damp. Damp that has been left untreated for years can cause timber rot (both wet rot and dry rot), compromised wall ties, and damaged joists. Dry rot in particular is a serious and expensive problem that can spread rapidly through a building.
• Mortgage lender refusal. If the lender's valuer identifies significant damp, they may decline to lend until the issue is resolved. This effectively prevents the sale from completing unless the buyer can fund the purchase without a mortgage or the seller agrees to carry out the work first.
• Uncertain extent of the problem. Where a survey suggests damp but the full extent is unknown — for example, where damp may have spread behind dry-lining or under floors — the uncertainty itself can be enough to deter a buyer.

In each of these situations, being proactive is key. If you know your property has damp issues, getting a specialist survey and quotation for remedial work before you list gives you the information to negotiate from a position of knowledge rather than uncertainty.

Costs at a glance

Practical steps for sellers

If you are preparing to sell and your property has had damp proofing work, here is a practical checklist:

1. Locate your damp proof certificate and guarantee. Check your property documents, solicitor's files, and the PCA database.
2. Check the guarantee expiry date and whether it is transferable. If the guarantee has expired, this is not necessarily a problem, but you should be prepared for the buyer to ask questions.
3. Inspect the property for visible signs of damp. Look for tide marks, salt deposits, mould, and peeling wallpaper or paint, especially at low level on ground floor walls.
4. If you find signs of damp, consider commissioning a specialist survey before marketing. This gives you a clear picture and puts you in control of the information.
5. Complete the TA6 form honestly, disclosing any past or present damp issues and any treatment carried out. See our guide on what to disclose when selling.
6. If the certificate is lost and the property shows no signs of damp, discuss indemnity insurance with your solicitor as a quick and cost-effective solution.
7. Gather all your documents needed for the sale early, including the DPC certificate, to avoid delays once an offer is accepted.

Sources

• Property Care Association (PCA) — property-care.org
• Royal Institution of Chartered Surveyors (RICS) — rics.org
• Building Research Establishment (BRE) — bregroup.com
• Law Society — TA6 Property Information Form, 5th edition, 2020
• Public Health Act 1875 — legislation.gov.uk

Related guides

• Damp Proof Course Guarantee: What Sellers Need
• Timber Treatment Guarantee for Sellers
• Roof Guarantee When Selling Your Property
• Cavity Wall Insulation Guarantee

Frequently asked questions