Buying a house: missing planning permission or building regulations?

 

You have found the house, made the offer and the conveyancing is moving along nicely. Then your solicitor emails: “We cannot find planning permission for the rear extension”, or perhaps it is the dormer, loft conversion, conservatory, garage or garden building.

It is an extremely common problem. It also causes more panic than it should, because no planning permission on the council website does not automatically mean the work is unauthorised.

The work may have been permitted development, may not have amounted to development at all, may be too old for planning enforcement, or the paperwork may simply be missing from an incomplete historic record. Building Regulations are a separate question again.

This guide explains what a buyer can check, what the seller can do, when a certificate of lawfulness may solve the problem, when retrospective planning permission may be sensible, and why retrospective building control can be much more invasive than people expect.

 

 

First: planning permission and Building Regulations are different

 

This is the most important distinction on the page.

Planning asks whether the development was permitted in land-use terms. An extension, dormer or outbuilding might have express planning permission, might be permitted development under the GPDO, might not be development at all, or might have become lawful through the passage of time.

Building Regulations deal with matters such as structure, fire safety, insulation, ventilation, drainage, stairs and electrical safety. Work can be perfectly lawful in planning terms and still have a Building Regulations problem. Equally, a Building Regulations completion certificate does not prove that planning permission existed.

So when a solicitor says “there is no permission”, the first question should always be: which permission or certificate is actually missing?

• planning permission or evidence of permitted development
• a Building Regulations approval or completion certificate
• listed building consent
• approval required by a planning condition
• a separate electrical, glazing or other compliance certificate

Do not try to solve all of those with one application. They are different regimes.

There can also be private legal controls. Restrictive covenants, lease or freeholder consent, rights over the land and party wall matters are separate again. Planning permission, permitted development or a certificate of lawfulness does not override them. Your conveyancer should deal with those title questions separately; see our guide to matters which are not planning considerations.

 

Why the council website may show nothing

 

Modern council planning registers can give the impression that every alteration to every house should have an application number. That is simply not how the system works.

A missing record can mean several things:

• the work was permitted development and no application was required
• the work did not amount to development
• the council’s online records do not extend back far enough
• an old paper file has not been digitised
• the application sits under an old address or plot description
• the work was genuinely carried out without the permission that was required

Our guide to the planning register explains what councils are required to keep and why an online search is not always the whole planning history.

If the work is an extension, roof enlargement or outbuilding, check the relevant permitted development rules before assuming an application was needed. See our guides to house extensions, dormers and roof enlargements and outbuildings.

 

Permitted development is planning permission

 

This is where conveyancing enquiries often become muddled. Permitted development is not a loophole and it is not development carried out without permission. The GPDO grants planning permission nationally where the relevant limits and conditions are met.

That means a rear extension or dormer which complied with the permitted development rules did not need a separate householder planning application. The absence of a council decision notice is therefore exactly what you would expect unless the owner chose to apply for a lawful development certificate.

There are important checks. Permitted development rights may have been removed by an Article 4 direction or by a condition on an earlier planning permission. Flats do not enjoy the ordinary Part 1 householder rights, and some houses created through changes of use have restricted rights. The rules in force when the work was carried out can also matter.

If everybody agrees the work looks as though it was permitted development but the buyer, lender or solicitor wants formal evidence, the usual answer is not to apply retrospectively for planning permission. It is to consider a certificate of lawfulness.

 

Certificate of lawfulness: often the cleanest planning answer

 

A certificate of lawfulness of existing use or development, usually called a CLEUD or existing lawful development certificate, can formally establish that existing work is lawful.

There are two common routes in a house purchase:

• the extension, dormer or other work was lawful from the start because it did not need planning permission or it complied with permitted development rights
• the work originally breached planning control but enough time has passed that enforcement action can no longer be taken

A certificate is evidence based rather than a fresh judgment on whether the council likes the development. The applicant normally needs to show the facts on the balance of probabilities.

Useful evidence can include dated photographs, invoices, building contracts, historic sale particulars, survey reports, Building Control records, aerial imagery and witness or statutory declarations. The evidence should establish both what was built and, where immunity through time is relied upon, when it was substantially completed.

For a buyer, a certificate can turn a vague “the extension has been there for years” into a formal planning document that stays with the property. For work that has already been carried out, the relevant route is normally an existing lawful development certificate under section 191. A certificate of lawfulness of proposed use or development under section 192 is for work or a use that is still proposed; it is not the route for retrospectively certifying an extension or dormer that already exists.

 

The planning enforcement time limits changed on 25 April 2024

 

This is the date to remember. The Levelling-up and Regeneration Act changes removed the old four-year rule for new breaches, but transitional provisions preserved it for earlier operational development.

Government enforcement guidance currently summarises the position in England as follows:

• operational development substantially completed before 25 April 2024 normally retains the old four-year enforcement period
• operational development substantially completed on or after 25 April 2024 normally has a ten-year enforcement period
• a change of use to a single dwellinghouse made before 25 April 2024 normally retains the old four-year period
• a change of use to a single dwellinghouse made on or after 25 April 2024 normally has a ten-year period
• other material changes of use and most breaches of condition have long been subject to a ten-year period

So an extension completed in 2018 is not suddenly subject to a ten-year planning enforcement clock just because the law changed in 2024. If it was substantially complete before 25 April 2024, the transitional rules matter.

The exact date of substantial completion can become critical, particularly for work carried out around 2024. There are also exceptions and complications, including deliberate concealment and previous enforcement action, so do not treat a rough age given by an estate agent as proof of immunity. See the government’s planning enforcement guidance.

 

If it is old enough, why bother with a certificate?

 

Because “too late to enforce” and “easy to sell” are not the same thing.

An old unauthorised extension may be lawful through the passage of time, but without a certificate the buyer is still relying on somebody’s view of the evidence. The same question may return when the buyer remortgages or sells in five years.

A certificate of lawfulness is therefore often useful even where nobody expects the council to take action. It provides a formal answer to the planning question.

That does not fix Building Regulations. Planning immunity and Building Control are separate.

 

When retrospective planning permission may be the better option

 

If the development did need planning permission, is not protected by an enforcement time limit and cannot be shown to be permitted development, a retrospective planning application under section 73A may be the practical route.

The council assesses a retrospective application on its planning merits in much the same way as an application made before the work. Permission is not guaranteed. The council can refuse it and, if the development remains unauthorised, enforcement may follow.

This is why it is worth diagnosing the problem before somebody submits an application just to satisfy a conveyancing enquiry. If the work was already permitted development or is already lawful through time, asking for retrospective planning permission may be the wrong question.

In many sales the seller resolves the issue before exchange, because the seller has the evidence and remains in control of the property while any application is determined. A buyer can also proceed and deal with it later, but that becomes a commercial and legal decision involving the buyer, solicitor, lender and insurer.

 

You can apply before you own the house

 

You do not have to own the property to make the application. In England, anyone can apply for planning permission on someone else's land. So a buyer does not necessarily have to complete the purchase before an application is submitted. However, the application must include the correct ownership certificate and the owner and any relevant agricultural tenant must be notified where required. Making an application does not give the applicant any right to enter, build on or otherwise use land they do not own.

This can be useful during a purchase. Subject to the seller's cooperation over access, plans and information, a buyer may be able to seek planning permission before committing to completion rather than buying first and hoping the planning problem can be solved afterwards. See the government's ownership certificate guidance.

 

What about an indemnity policy?

 

Conveyancers sometimes propose indemnity insurance where planning or Building Regulations paperwork is missing. This can be useful in a transaction, particularly where a lender is content with it, but it is important to understand what it does.

An indemnity policy does not make an extension lawful, prove that a loft is structurally safe or create a Building Regulations completion certificate. It is an insurance product dealing with specified financial risks if a problem later arises.

Policies can also contain strict conditions. Contacting the council about the suspected breach before the policy is arranged can affect whether cover is available. If indemnity insurance is being considered, take advice from the conveyancing solicitor before approaching the council.

 

Building Regulations: first check whether there really is no record

 

Before considering retrospective Building Control, establish what happened when the work was carried out. The job may have been supervised by the local authority or, particularly in more recent years, by a private approved inspector or registered building control approver.

Ask the seller for:

• the original Building Regulations application or building notice
• approved plans if they exist
• inspection records
• a completion or final certificate
• details of the building control body or approved inspector
• structural calculations and engineer’s drawings
• electrical, glazing, boiler or other relevant certificates

Some councils can provide copies of old completion certificates. An absent document in the seller’s folder does not necessarily mean Building Control was never involved.

Our Building Regulations guide explains the approval system in more detail.

 

Retrospective Building Control is called regularisation

 

For unauthorised building work, the Building Regulations provide a retrospective route called regularisation. It is different from retrospective planning permission.

A regularisation application can be made to a local authority building control body for qualifying unauthorised work carried out after 11 November 1985. The local authority can require information, plans and whatever reasonable investigation is needed to decide whether the work complies.

This is where loft conversions can become awkward. Building Control may need parts of the finished work to be opened up so that hidden construction can be inspected. Depending on the work, that might mean exposing floor joists or steelwork, opening ceilings or walls, checking insulation, testing drainage or electrics, and confirming fire precautions and the staircase arrangement.

Regularisation can therefore be far more invasive than a planning certificate, which is largely a documentary and legal exercise.

 

Does regularisation mean meeting today’s Building Regulations?

 

Generally, no. This is a common misunderstanding.

The regularisation process looks at the relevant Building Regulations requirements that applied when the unauthorised work was originally carried out. Government guidance on regulation 18 expressly refers to securing compliance with the Building Regulations that were in force when the work was done.

That does not make regularisation easy. The difficulty is often proving how concealed work was built and whether it met those requirements. Building Control can require opening up, tests and remedial work before issuing a regularisation certificate.

The government’s current Building Regulations application guidance confirms that regularisation is retrospective approval and that alterations may be required before a certificate is issued.

 

Building Control also has its own enforcement clock

 

Do not apply the planning four-year rule to Building Regulations.

The Building Safety Act 2022 strengthened Building Control enforcement. Section 36 of the Building Act 1984 now allows a building control authority to require the alteration or removal of non-compliant work for up to ten years after completion. The strengthened provisions came into force on 1 October 2023 and can apply to older projects where the relevant legal conditions are met.

That is separate from the planning enforcement periods above. A ten-year-old extension might be lawful in planning terms yet still have unresolved Building Regulations evidence. An older job may be outside the usual section 36 notice period, but that still does not create a completion certificate or prove the construction is safe.

 

The loft conversion problem

 

Lofts are probably the most difficult version of this conveyancing problem because so much of the important construction is hidden.

Planning permission may never have been required. A roof enlargement can often fall within permitted development under Part 1 Class B, while rooflights are usually considered under Class C. But a conversion to habitable accommodation will normally engage Building Regulations even if the exterior change is permitted development.

You will often hear an unapproved loft described as “storage only”. That is a useful warning for a buyer, but it is not a magic legal cure. The absence of a Building Regulations certificate does not automatically prove that the room is unsafe, and calling it storage does not retrospectively make non-compliant structural work compliant.

For purchase and valuation purposes, however, a buyer should be cautious about treating an undocumented loft as a compliant bedroom or habitable room. A lender, surveyor or solicitor may refuse to count it as such unless satisfactory evidence is produced.

Before seeking regularisation, consider how invasive the investigation may be. A Building Control officer cannot certify hidden floor strengthening, steelwork, insulation or fire protection simply because the room looks nicely finished.

 

Extensions, conservatories and outbuildings

 

The same basic process applies to other common additions, but the answer can be easier.

Extensions: first check whether the work had express planning permission or complied with the permitted development rules in force at the time. Building Regulations will usually have applied, so look separately for the completion certificate.

Conservatories: some are exempt from parts of the Building Regulations if the exemption criteria are met, but the planning position is separate. See our guide to conservatories.

Outbuildings: many garden buildings are permitted development under Class E, but the use and position matter. A building used as a separate dwelling is not simply an incidental Class E outbuilding. Small detached buildings can also fall within Building Regulations exemptions in certain circumstances. See our outbuilding guide.

 

Listed buildings need special care

 

If the house is listed, do not assume the ordinary planning enforcement time limits solve historic alterations.

Listed building control is different. Government guidance confirms that there is no time limit for issuing a listed building enforcement notice, and unauthorised works which require listed building consent can also amount to a criminal offence. An application can be made under section 8(3) of the Planning (Listed Buildings and Conservation Areas) Act 1990 for consent to retain works already carried out. However, that is not a clean retrospective cure in the ordinary planning sense: consent to retain the works does not remove any criminal liability that may already have arisen from carrying them out without the required listed building consent.

This can be highly relevant to old windows, internal walls, fireplaces, extensions and roof alterations discovered during a purchase. A listed building purchase with unexplained historic work needs specific advice.

 

A practical buyer’s checklist

 

1. Identify the exact work – extension, dormer, loft conversion, outbuilding, internal alteration or change of use
2. Identify what document is missing – planning, Building Regulations, listed building consent or something else
3. Check the planning history properly rather than relying only on a quick online address search
4. Check whether planning permission was needed and whether permitted development rights were available at the time
5. Establish the date of substantial completion if planning enforcement immunity may be relevant
6. Collect evidence before deciding whether a certificate of lawfulness is appropriate
7. Trace Building Control records separately and identify who supervised the work
8. Think carefully before regularisation, especially for a finished loft conversion where opening up may be required
9. Speak to the conveyancing solicitor before contacting the council if an indemnity policy is being considered
10. Decide who will resolve it – seller before exchange, buyer after completion, or neither if the risk is understood and accepted

 

What are the realistic options?

 

There is no single answer, but most cases end up in one of these routes:

• Do nothing because the work did not require the missing consent and the buyer, lender and solicitor are satisfied
• Find the missing paperwork from the council, former Building Control body, previous owner or professional team
• Obtain a certificate of lawfulness where the planning position can be formally established
• Apply for retrospective planning permission where permission was required and the development is still enforceable
• Seek Building Regulations regularisation where the benefit of a formal certificate justifies the inspection, opening up and remedial work that may be required
• Use indemnity insurance where the solicitor and lender consider that an appropriate transaction solution
• Renegotiate or walk away where the uncertainty, safety issue or cost of remedial work changes the value of the purchase

The key is to choose the solution for the actual problem. A solicitor being unable to find a planning application is the start of the investigation, not proof that the house has an unlawful extension.

 

Need help checking a house before you buy?

 

Planning Geek can review the planning history, permitted development position and enforcement time limits, and advise whether a certificate of lawfulness or retrospective application is the sensible planning route. We do not act as Building Control inspectors, but we can separate the planning issue from the Building Regulations issue so you know exactly what still needs resolving.

If you would like us to review a property, please complete our fee proposal form.

 

Page Created: 29th August 2026

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