selling

Selling a house without a building regulations completion certificate: your options

Selling a house with no building regulations completion certificate for an extension: regularisation, indemnity insurance and time limits explained.

4 min read
Last reviewed 4 November 2026
By Your Property Check team

Part 1 of 7

Why buyers ask for the certificate

General information, not advice. Building regulations are separate from planning permission. Under the Building Regulations 2010 many extensions, conversions and alterations need building control approval, and when the work is finished the building control body issues a completion certificate. GOV.UK says the rules are enforced by the building control body, usually your local authority or a private registered approver, and that "without approval you will not have the certificates of compliance you may need when you want to sell your home". A buyer's solicitor and lender look for these papers because they show the work was checked. When they are missing, the solicitor raises it as a query (see our explanation of the TA6 property information form).

Part 2 of 7

What can happen if work had no approval

GOV.UK says the person doing the work could be prosecuted and fined, and that the building control body can require you to pay to correct faulty work. Section 36 of the Building Act 1984 sets a limit on one power: a notice requiring removal or alteration of work that breaks the regulations cannot be given after 10 years from the completion of the work. It adds an exception where a building control application was made and granted for work that is not higher-risk building work, and the work followed the approved plans. Contravening the regulations is also an offence under section 35. Planning law has its own limits, covered below. We found no source for a 12-month enforcement window, so we do not use one.

Part 3 of 7

Your options

Option	What it involves	Time and who pays	When it may be enough
Regularisation	A retrospective application to the local authority for work done without consent	The owner pays. The fee varies with the work and no amount is published on the page we read	When the council inspects and is satisfied the work complies
Indemnity insurance	A policy that covers the buyer for some risk from the missing papers	Traditionally paid by the seller, though it can be negotiated; we quote no premium	When the buyer's solicitor and lender accept it
Lawful development certificate	A planning certificate that the existing use or building is lawful for planning	A fee is payable and no amount is published on the page we read; decision period eight weeks	For a planning question, not a building regulations one
Disclose and negotiate	Tell the buyer, answer the solicitor's queries and agree a price or conditions	Agreed between the parties	When the buyer is comfortable and the lender agrees

Part 4 of 7

Regularisation

The Planning Portal describes regularisation as a retrospective application for previously unauthorised work. It covers work done without building regulations consent that started on or after 11 November 1985, and the page says it is needed "even if the work was done before you became owner of a property". The level of detail depends on the size of the breach: you will often need a description and plans if available, and the work may need to be exposed, removed or rectified to show compliance. The authority inspects to decide whether it complies or what must change. Contact your local building control service before applying.

Part 5 of 7

Indemnity insurance

Our indemnity insurance guide lists missing planning permission or building regulations approval among the situations a policy can cover. A policy does not fix the underlying issue. Whether it is accepted is up to the buyer's solicitor and lender. Our guide to indemnity insurance explains how it works and who pays. We quote no premium because no source we read gives one.

Part 6 of 7

Lawful development certificates and planning

Building regulations and planning are different. Extensions can also need planning permission. In England, GOV.UK's enforcement guidance says development generally becomes immune from enforcement after a set period: 4 years from substantial completion for building works completed before 25 April 2024, and 10 years for work completed on or after that date. It also lists exceptions. The Planning Portal says a lawful development certificate confirms that an existing use or building is lawful for planning; it is optional, a fee is payable and councils should decide within eight weeks. You can check what planning history a property has with the planning applications tool.

Part 7 of 7

A sensible order of steps

Look for the paperwork: the original building control file, a completion certificate, or a regularisation certificate. Ask the previous owner's solicitor if you bought recently.
Ask your local building control service what it holds and how a regularisation application would work.
Tell your solicitor early, so replies to the buyer's queries are consistent.
Ask the solicitor whether indemnity insurance would be accepted and who would pay.
Remember that what stays with the house matters too; see what stays with a house when you sell and the notes on restrictive covenants.

This page is general information, not advice.

Our take

Close the paperwork gap before the buyer's solicitor finds it

You can still sell without a completion certificate, but the buyer's solicitor will ask for evidence. The usual routes are regularisation, indemnity insurance or both, and a policy does not fix the underlying issue. We think the best course is to establish early what work was done, because building regulations and planning are separate questions.

What Your Property Check adds: our planning applications tool is where to look at an address's planning history, and the property checker puts planning beside sold prices, EPC, crime, flood and council tax for the same address.

Check planning history

Our opinion, drawn from the facts on this page: not advice and not a forecast. We earn from OfferCheck reports and from introducing sellers to cash buyers, so weigh it with that in mind (see our disclosure). We are not authorised or regulated by the FCA.

Questions, answered

Frequently asked questions

What if my extension has no completion certificate?

You can still sell, but expect questions from the buyer's solicitor. Ask your council about regularisation, which applies to work started on or after 11 November 1985, and ask your solicitor about indemnity insurance.

What is regularisation?

A retrospective application to the local authority for work done without building regulations consent. The Planning Portal says it may need the work to be exposed, removed or rectified, and that the fee varies with the work.

Does indemnity insurance cover missing certificates?

It can cover a buyer for some risk from missing building regulations papers, if the buyer's solicitor and lender accept it. It does not make the work compliant. Our indemnity insurance guide has the details.

Do I need a lawful development certificate?

Not for building regulations. It is a planning certificate and is optional. The Planning Portal says a fee is payable and councils should decide within eight weeks.

How long can the council take action on unapproved work?

Section 36 of the Building Act 1984 bars a notice requiring removal or alteration after 10 years from completion, with an exception for approved, followed plans. Planning enforcement has separate limits in England of 4 or 10 years depending on when the work was completed.

Where this comes from

Sources

Last reviewed 4 November 2026 by the Your Property Check team. This page is general information, not legal, tax or financial advice. For your own situation, speak to a conveyancing solicitor or another qualified professional.