Building Control Completion Certificate Explained

When building work is carried out at a property, the local authority or an approved inspector needs to confirm that the finished result complies with the Building Regulations. The document that proves this is the building control completion certificate. It is one of the most commonly requested documents during the conveyancing process, and its absence is one of the most frequently raised conveyancing enquiries.

This guide covers what the completion certificate is, how it differs from building regulations approval, which types of work require one, and what your options are if the certificate is missing when you come to sell.

What is a building control completion certificate?

A building control completion certificate is a formal document issued by your local authority building control (LABC) or by an approved inspector. It confirms that notifiable building work has been inspected at its final stage and that the completed work complies with the Building Regulations 2010.

The certificate may also be referred to as a completion notice, a final certificate (when issued by an approved inspector), or simply a building regulations completion certificate. Regardless of the name, the purpose is the same: it provides official confirmation that the work was built to the standard required by law.

The completion certificate is the document that the buyer's solicitor and mortgage lender expect to see when building work has been disclosed. Without it, there is no independent verification that the work is safe and structurally sound. This is why it features prominently in the property certificate pack that sellers are expected to provide.

Completion certificate vs approval notice

One of the most common points of confusion is the difference between the building regulations approval notice and the completion certificate. They are two separate documents issued at different stages of the process:

Having an approval notice without a completion certificate is a common scenario. The homeowner may have obtained approval, carried out the work, but never booked the final inspection or forgot to collect the certificate. From the buyer's solicitor's perspective, an approval notice alone is not sufficient. It does not confirm that the work was built correctly — only that the plans were acceptable before construction began.

When is a completion certificate required?

A completion certificate is required for any building work that is classified as “notifiable” under the Building Regulations 2010. The following types of work require building regulations approval and, on completion, a completion certificate:

• Extensions (single-storey and multi-storey)
• Loft conversions
• Garage conversions
• Removing or altering load-bearing walls or structural elements
• Installing new boilers, heating systems, or unvented hot water cylinders
• Electrical work in kitchens, bathrooms, and outdoors (unless carried out by a Part P registered electrician under a competent person scheme)
• Replacing windows and external doors (unless installed by a FENSA-registered or CERTASS-registered installer who self-certifies)
• Underpinning
• Adding or altering drainage
• Significant changes to a building's thermal elements (roof insulation, wall insulation) during renovation

Work that does not require a completion certificate includes cosmetic changes such as painting, plastering, replacing floor coverings, and fitting new kitchen units on a like-for-like basis. If the work at your property falls outside the notifiable categories, the absence of a certificate is not a conveyancing issue.

Why the certificate matters when selling

The completion certificate becomes important during the conveyancing process for two main reasons: the local authority search and the TA6 Property Information Form.

The local authority search

As part of the standard property searches, the buyer's solicitor orders a local authority search. This search reveals any building regulations applications made for the property and whether a completion certificate was issued. If an application appears without a corresponding completion certificate, the solicitor will raise it as an enquiry.

The TA6 form

Section 6 of the TA6 alterations section asks whether any building work or alterations have been carried out at the property and, if so, whether the necessary consents and certificates were obtained. As a seller, you are legally required to answer these questions honestly. If you disclose building work without a corresponding certificate, the buyer's solicitor will require the issue to be resolved before exchange.

Mortgage lender requirements

Most UK mortgage lenders follow the UK Finance Mortgage Lenders' Handbook, which requires the buyer's solicitor to report any building work that lacks a completion certificate. The lender will then decide whether to proceed and what evidence they need. In practice, most mainstream lenders accept either a regularisation certificate or indemnity insurance. However, for recent or structural work, some lenders may specifically require regularisation rather than insurance.

How to obtain a completion certificate

If building work at your property is currently in progress or has recently been completed, the process for obtaining a completion certificate is straightforward:

1. Book the final inspection. Contact your local authority building control department (or the approved inspector overseeing the work) and request a final inspection. This is the inspection that takes place once all the work is finished.
2. Prepare for the inspection. The building control officer will check the finished work against the approved plans and the Building Regulations. Make sure all work is complete, accessible, and visible. If certain elements have been covered up (for example, steelwork concealed behind plasterboard), you may need to provide photographs or structural engineer's certificates taken during construction.
3. Receive the certificate. If the work passes the final inspection, the completion certificate is issued. Timescales vary by local authority — some issue the certificate on the day, while others take two to four weeks.
4. Address any defects. If the inspector identifies issues, you will need to carry out remedial work before the certificate can be granted. A follow-up inspection will be required once the defects are resolved.

What to do if the certificate is missing

If you are preparing to sell and discover that a completion certificate was never issued for building work at your property, you have several options depending on the circumstances.

1. Request a duplicate

If the certificate was issued but you have lost the physical copy, contact your local authority building control department. Most councils keep records of completion certificates and can reissue them for a small administrative fee, typically £20 to £50. Some local authorities also have online portals where you can search for building control records by property address.

2. Request the final inspection

In some cases, the building work may have had all the interim inspections but the final inspection was never booked. If building control has records of the application and earlier inspections, they may be able to carry out the final inspection now and issue the certificate — provided the work is still accessible and can be assessed. This is not always possible if the work was completed many years ago and has since been covered up or altered.

3. Apply for regularisation

If the work was completed without any building regulations notification, or if the final inspection was never carried out and the work is now covered up, you can apply for regularisation under regulation 18 of the Building Regulations 2010. This is a retrospective application that involves the local authority inspecting the finished work and, if satisfied, issuing a regularisation certificate.

Regularisation may require opening up parts of the structure (for example, removing plasterboard to check steelwork or lifting floorboards to inspect joists). The fee is typically 1.5 to 2.5 times the standard building control fee, and the process takes four to ten weeks. For a detailed breakdown of the process, see our guide on building regulations sign-off missing.

4. Take out indemnity insurance

If regularisation is not practical or cost-effective — for example, if the work was completed many years ago and the enforcement risk is minimal — indemnity insurance is the alternative. A one-off policy typically costs £50 to £300 and covers the buyer and their lender against the financial risk of the local authority taking enforcement action in the future.

Indemnity insurance does not certify that the work complies with the Building Regulations. It simply provides financial protection. Most mortgage lenders accept indemnity insurance for work completed more than 12 months ago, which is the time limit for local authority enforcement under Section 36 of the Building Act 1984.

There is one critical condition: you must not have contacted the local authority about the work before taking out the policy. If the local authority has been notified or approached, most insurers will not issue a policy or will void an existing one. This means you need to decide between regularisation and indemnity insurance before taking any action. Discuss the options with your solicitor first.

Regularisation vs indemnity insurance

For work completed more than 12 months ago that appears to be in good condition, indemnity insurance is the faster and cheaper solution and is accepted by most buyers and lenders. For recent work, structural alterations, or situations where you want to provide the strongest reassurance, regularisation is the better option.

Competent person schemes and self-certification

Some types of building work can be self-certified by the installer under a government-approved competent person scheme, which means a separate completion certificate from building control is not required. The most common examples are:

• FENSA and CERTASS — for replacement windows and external doors. A registered installer self-certifies compliance with Part L of the Building Regulations and notifies the local authority. The FENSA or CERTASS certificate serves as the equivalent of a completion certificate.
• Gas Safe Register — for gas appliance installations. A Gas Safe registered engineer self-certifies under the competent person scheme for Part J (combustion appliances and fuel storage systems).
• NICEIC, NAPIT, ELECSA, and STROMA — for electrical work under Part P. A registered electrician can self-certify notifiable electrical work and notify the local authority directly.
• HETAS and OFTEC — for solid fuel and oil-fired heating installations respectively.

If the work was carried out by an installer registered with one of these schemes, you should have their certificate rather than a building control completion certificate. The buyer's solicitor will accept the competent person certificate as equivalent. If this certificate is missing, the same options apply — check with the scheme, request a duplicate, or consider indemnity insurance. For more on handling missing documentation from installers, see our guide on selling a house with missing guarantees.

Common situations where certificates are missing

In practice, a missing completion certificate surfaces in several recurring scenarios:

• Work done by a previous owner. You bought the property without realising that an extension, loft conversion, or structural alteration was never formally signed off. The local authority search during your buyer's conveyancing reveals the gap. If you purchased the property with indemnity insurance already in place, check whether it is still valid and provides adequate cover before arranging a new policy.
• Builder did not book the final inspection. The building work was carried out with proper approval, but the builder or homeowner never arranged the final inspection. The approval notice exists, but the completion certificate does not. Contact building control to arrange the final inspection if the work is still accessible.
• DIY work carried out without notification. The homeowner carried out notifiable work themselves without applying for building regulations approval. This is particularly common for internal structural work such as removing a wall. Regularisation is the appropriate route here.
• Windows replaced by a non-FENSA installer. Replacement windows were installed by a company not registered with FENSA or CERTASS, and no building control application was made. Indemnity insurance is the most common resolution for older window replacements.

The Section 36 enforcement time limit

Understanding the enforcement time limit is important when deciding how to resolve a missing certificate. Under Section 36 of the Building Act 1984, the local authority has 12 months from the date the work was completed to take enforcement action requiring the property owner to alter or remove non-compliant work.

After this 12-month window has passed, the local authority can no longer compel you to undo the work. The work remains technically non-compliant (the local authority can still refuse to issue a completion certificate), but the practical enforcement risk drops to near zero. This is the main reason indemnity insurance is both affordable and widely accepted for work that was completed more than a year ago.

For work completed within the last 12 months, the enforcement risk is real, and regularisation is the more appropriate route. If you are unsure when the work was done, your solicitor can help you assess the risk and advise on the best course of action.

How the completion certificate fits into your sale

When preparing to sell your home, the completion certificate is part of the wider documentation package. Here is how it fits into the process:

1. Gather your documents early. Before listing, collect all building control certificates, competent person scheme certificates, planning permissions, and related paperwork. These form part of your property certificate pack.
2. Complete the TA6 accurately. Declare all building work you are aware of in the alterations section of the TA6 and state whether certificates are available. Honesty here is not optional — misrepresentation on the TA6 can lead to legal claims after completion.
3. Resolve gaps before marketing. If you know a completion certificate is missing, address it before listing. Starting the regularisation process or arranging indemnity insurance early avoids delays once you are under offer. If you are arranging retrospective building regulations approval, allow four to ten weeks for the process.
4. Respond to enquiries promptly. If the buyer's solicitor raises the missing certificate as a pre-contract enquiry, respond with the solution you have arranged (regularisation certificate or indemnity insurance policy). The faster you respond, the less likely the issue is to cause delay.

Practical tips for sellers

• Check your local authority's building control records. Many councils have online portals where you can search for building control applications and completion certificates by property address. This is a quick way to identify any gaps before you instruct a solicitor.
• Do not contact the local authority if you plan to use indemnity insurance. Once building control has been notified or approached about the work, indemnity insurance is no longer available. Decide your approach with your solicitor first.
• Keep certificates safe for the future. When you receive a completion certificate, regularisation certificate, or competent person scheme certificate, store it with your other property documents. Digital copies are helpful as a backup.
• Consider the cost of delay. Resolving a missing certificate during an active sale can take weeks and creates stress for both parties. Dealing with it before you market the property puts you in control of the timeline.

Sources

• Building Regulations 2010, regulation 17 (completion certificates) and regulation 18 (regularisation) — legislation.gov.uk
• Building Act 1984, Section 36 (enforcement of building regulations) — legislation.gov.uk
• Local Authority Building Control (LABC) — labc.co.uk
• GOV.UK — Building regulations: when to apply (planning portal)
• UK Finance Mortgage Lenders' Handbook — ukfinance.org.uk
• FENSA (Fenestration Self-Assessment Scheme) — fensa.org.uk
• Law Society — TA6 Property Information Form, 4th edition
• Construction Industry Council (CIC) — Approved Inspectors Register — cic.org.uk

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Frequently asked questions