What Is Planning Permission? And Building Without It

If you are planning to extend your home, convert a garage, build an outbuilding, alter the structure of your property or change the way a building is used, one of the first questions you should ask is: Do I need planning permission?

Planning permission is an important part of the property development process in England. However, planning permission is only one part of obtaining the necessary approvals for building work. Depending on the project, you may also need Building Regulations approval, inspections during construction and, when the work is complete, a completion certificate or other evidence of building control compliance.

Understanding the difference between planning permission and Building Regulations approval can help property owners avoid costly problems, particularly when selling or remortgaging a property.

This guide explains what planning permission is, why planning approval matters, what a completion certificate is, the difference between planning permission and Building Regulations, and what you can do if building work has already been carried out without the correct consent.

Important: Planning and building control requirements depend on the individual property, development and circumstances. This article focuses primarily on England. If you are dealing with a specific property, professional planning or building control advice may be appropriate.

What Is Planning Permission?

Planning permission is formal approval from the local planning authority (LPA) for a proposed development.

The planning system exists to control development and consider how changes to buildings and land may affect matters such as:

• The appearance and character of an area

• Neighbouring properties

• Residential amenity

• Highways and parking

• The use of land and buildings

• Conservation areas

• Listed buildings

• Trees and landscaping

• Flood risk and other environmental considerations

• The wider planning policies that apply to the property

Not every building project requires a full planning application. Some work may benefit from permitted development rights, while other projects may require planning permission before work begins.

If planning permission is required, carrying out the development without it can create a breach of planning control. (GOV.UK)

Why Do You Need Planning Permission?

Planning permission provides a formal decision from the local planning authority that the proposed development is acceptable in planning terms.

For example, planning permission may be relevant when you are:

• Building a house extension

• Constructing a new dwelling

• Converting a building

• Changing the use of a property

• Building certain outbuildings

• Making significant external alterations

• Developing land

• Carrying out certain commercial or residential developments

The exact requirements depend on the proposed work and the planning history of the property.

Getting the correct planning approval before starting work can give you certainty about what you are legally entitled to build and can prevent potentially expensive enforcement problems later.

Planning Permission and Building Regulations Are Not the Same

One of the most common misunderstandings among homeowners is believing that planning permission automatically means the building work has been approved from a construction and safety perspective.

It does not.

Planning permission and Building Regulations approval are separate matters.

Planning permission generally deals with whether a development is acceptable in planning terms.

Building Regulations deal with how building work is designed and constructed, including areas such as:

• Structural safety

• Fire safety

• Ventilation

• Energy efficiency

• Drainage

• Electrical safety in relevant circumstances

• Access

• Health and safety

• Thermal performance

Planning Portal guidance confirms that retrospective approval may be required separately for planning and building control, depending on the work carried out. (Planning Portal)

This means that obtaining planning permission does not necessarily mean that you have obtained Building Regulations approval.

Likewise, having a Building Regulations approval does not automatically mean that planning permission was obtained.

What Is Building Regulations Approval?

Building Regulations approval is the building control process used to assess whether building work meets the applicable Building Regulations requirements.

Depending on the project, an application can involve full plans or other routes available under the building control system. GOV.UK explains that applications can generally be made through a local authority building control body or, where applicable, a registered building control approver. (GOV.UK)

Building control inspections may take place during the construction process.

The purpose is not simply to produce paperwork. Building control is intended to help establish that the completed work meets the relevant technical and safety requirements.

What Is a Completion Certificate?

A completion certificate is evidence associated with the building control process confirming that, following the relevant inspections and assessment, the completed building work complies with the applicable Building Regulations requirements.

For ordinary building work, the precise process and certificate will depend on who handled the building control application and the type of project.

GOV.UK states that under the standard building control process, a completion certificate will usually be issued following satisfactory completion of the building work and the necessary assessment. (GOV.UK)

A completion certificate is therefore an important document to retain with the property’s records.

Why Is a Completion Certificate Important?

A completion certificate can become particularly important when you later decide to:

• Sell your property

• Remortgage your property

• Carry out further alterations

• Provide evidence of compliance

• Deal with a solicitor or conveyancer

• Demonstrate the history of building work

• Resolve questions about previous alterations

A buyer’s solicitor may ask for evidence that extensions, conversions or structural alterations received the appropriate approvals.

If the paperwork cannot be located, this does not necessarily mean that the building work is unlawful. However, it can create additional questions and may require further investigation.

This is why homeowners should keep copies of:

• Planning permissions

• Approved plans

• Planning decision notices

• Building control approvals

• Inspection records

• Completion certificates

• Structural calculations

• Architect’s drawings

• Specialist certificates

• Any lawful development certificates

• Any regularisation certificates

What Happens If You Have Carried Out Building Work Without Planning Permission?

If you have already carried out work and subsequently discover that you did not obtain the required planning permission, do not ignore the situation.

The correct solution depends on the nature of the development, when the work was carried out, the planning history and whether the development actually requires planning permission.

There are several possible routes.

1. Establish Whether Planning Permission Was Actually Required

Before applying for retrospective planning permission, establish whether the work required permission in the first place.

Some developments may have been permitted under permitted development rights.

In other cases, a Lawful Development Certificate (LDC) may be appropriate to establish the lawfulness of existing development or use.

A Lawful Development Certificate can provide legal confirmation of the lawfulness of qualifying past or existing development. (Planning Portal)

This is an important distinction: you should not automatically assume that every piece of work without a planning application is unlawful.

2. Consider a Retrospective Planning Application

If the development did require planning permission and has already been constructed, you may be able to make a retrospective planning application.

Planning Portal explains that a local authority can request a retrospective application for development that has already been carried out without the required permission. However, retrospective planning permission is not guaranteed. The application is assessed through the normal planning process. (Planning Portal)

This is why retrospective planning applications should be prepared carefully.

The planning authority will consider the development against relevant planning policies and other material considerations.

3. What If the Retrospective Planning Application Is Refused?

A refusal does not simply disappear.

If retrospective permission is refused, the local planning authority may take enforcement action and can require the unauthorised development to be altered or, in appropriate circumstances, removed.

Planning Portal states that where retrospective permission is refused, the authority may require the property to be returned to its previous state. (Planning Portal)

This is why it is generally better to obtain professional advice before submitting a retrospective application, particularly where the development is substantial or there is a risk of enforcement.

What If You Also Have No Building Regulations Approval?

This is a separate issue.

You could potentially have:

Planning permission but no Building Regulations approval

or

Building Regulations approval but no planning permission.

You could also have neither.

If building work has already been completed without the necessary Building Regulations approval, you may be able to apply for regularisation.

GOV.UK describes regularisation as retrospective approval for building work that has already been carried out without consent. It is generally available through the local authority building control body, and work may need to be exposed, altered or corrected before compliance can be established. (GOV.UK)

If successful, the process can result in a regularisation certificate.

A regularisation certificate is therefore different from retrospective planning permission.

Retrospective Planning Permission vs Regularisation Certificate

The distinction is important.

One certificate does not replace the other.

If both planning permission and Building Regulations approval were required, you need to address both.

What Should You Do If You Have Already Built Without Consent?

If you have discovered that previous building work was carried out without the correct approvals, a sensible starting point is to establish exactly what happened.

Step 1: Find Out What Work Was Carried Out

Prepare a detailed record of the development.

This could include:

• What was built or altered

• The approximate dimensions

• When the work was completed

• Whether the property was extended

• Whether the roof was altered

• Whether structural walls were removed

• Whether the use of the building changed

• Whether drainage was altered

• Whether windows or doors were changed

• Whether the property is listed or in a conservation area

• Whether previous planning applications exist

Photographs, invoices, architectural drawings and previous property documents can all be useful.

Step 2: Check the Planning History

Search the local planning authority’s records to establish whether permission was previously granted.

You may discover that:

• Planning permission already exists

• The work was approved under an older application

• The work benefited from permitted development rights

• A condition was imposed that affects the development

• No planning application was ever submitted

This investigation can prevent you from making an unnecessary application.

Step 3: Check the Building Control Records

You should also investigate whether Building Regulations approval was obtained.

Ask:

Was a Building Regulations application made?

If so:

Was the work inspected and was a completion certificate issued?

If the original certificate has simply been lost, you may be able to obtain evidence or a copy from the relevant building control body, depending on the circumstances.

Step 4: Get Professional Advice Where Appropriate

For complicated or high-value projects, consider obtaining advice from a suitably qualified:

• Planning consultant

• Architect

• Architectural technologist

• Structural engineer

• Building control professional

• Property solicitor

A professional can help establish what approvals are missing and what route is most appropriate.

Do Not Assume That “Old Work” Automatically Means You Are Safe

There are specific rules surrounding planning enforcement, immunity periods and lawful development.

The age of a development can be highly relevant, but it is not sensible to rely solely on the fact that an extension or alteration has existed for a long time.

The circumstances and evidence matter.

Where appropriate, a Lawful Development Certificate can provide formal confirmation of lawfulness. (Planning Portal)

If you are relying on the age of development, it is particularly important to obtain appropriate evidence and professional advice.

Why You Should Resolve Missing Planning and Building Control Documents Before Selling

One of the worst times to discover an approval problem is when you are already negotiating a property sale.

A buyer may ask questions about:

• Extensions

• Loft conversions

• Garage conversions

• Structural alterations

• New outbuildings

• Changes of use

• Planning permissions

• Building Regulations approvals

• Completion certificates

If documentation is missing, the transaction can become more complicated.

Depending on the circumstances, your solicitor may need to investigate the position and advise on the available options.

Resolving planning and building control issues before putting a property on the market can therefore make the conveyancing process considerably smoother.

Common Planning Permission Mistakes

“My builder said I didn’t need permission.”

A builder’s opinion is not necessarily a substitute for planning advice or confirmation from the relevant authority.

“The extension is small, so I don’t need planning permission.”

Size alone does not determine whether planning permission is required. Permitted development rules have specific limitations and conditions.

“My neighbour has done the same thing.”

Another property’s planning history does not automatically determine whether your development is lawful.

“I have planning permission, so everything is approved.”

Planning permission and Building Regulations are separate.

“The previous owner built it, so it isn’t my problem.”

If you own the property, missing documentation can still become your problem when you sell, remortgage or undertake further work.

“It was built years ago, so it must be legal.”

The age of development can be relevant, but you should establish the legal position rather than simply assume it.

Planning Approval and Completion Certificates: The Bottom Line

When undertaking building work, it is important to think beyond the question:

“Do I need planning permission?”

You should also ask:

“Do I need Building Regulations approval?”

and, once the project is finished:

“Do I have the appropriate completion documentation?”

Planning permission deals broadly with whether development is acceptable from a planning perspective, while Building Regulations concern the technical standards applicable to the construction.

If work has already been completed without the correct approvals, there may still be routes available to resolve the situation. These can include a retrospective planning application, a Lawful Development Certificate, Building Regulations regularisation, or other appropriate action, depending on the circumstances. (Planning Portal)

The most important thing is not to ignore the problem.

The earlier you identify missing approvals, the more options you may have for resolving them before they become an issue during a sale, remortgage, future extension or planning application.

Final Thoughts

Planning permission, Building Regulations approval and completion certification all play important roles in the property development process.

Before starting work, establish exactly what approvals are required. During construction, make sure the appropriate building control inspections take place. Once the work is finished, obtain and retain the relevant completion documentation.

And if you have already carried out work without planning permission or Building Regulations approval, don’t panic—but don’t ignore it either.

Start by investigating the planning history and building control records. Then determine whether the work was permitted development, whether a Lawful Development Certificate may be appropriate, whether retrospective planning permission is required, and whether Building Regulations regularisation is necessary.

Taking action early can help protect the value of your property and reduce the risk of complications when you eventually decide to sell, remortgage or carry out further development.

For official guidance, see the Planning Portal and GOV.UK Building Regulations guidance.