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Jane Rarok | 11th November 2020

Planning guide to extending your home


Jane Rarok | 11th November 2020

Planning guide to extending your home

This blog contains our planning guide for homeowners wishing to extend their property, construct an outbuilding or create an annex.

Are you considering extending your home or adding an outbuilding? Maybe you need more room to be able to work from home or want to provide an annex to accommodate an older or vulnerable member of your family?

Planning guide

This planning guide looks at what type of extension or outbuilding you require and what you could achieve using permitted development rights.

Consider the options for your home.

  • What do you want to use the space for?
  • What kind of space do you need: an extension, a loft or garage conversion, a granny annex, a home office in the garden?
  • Where could it be located?

Do you need planning permission for your extension or outbuilding?

Finding out whether planning permission is required for your extension or outbuilding is an important step when considering your options.

Permitted development rights

  • Many houses benefit from what are called ‘permitted development rights’. This is the right to undertake certain types of development without the need for planning permission.
  • Permitted development rights allow you to extend or add to your property, subject to specific criteria.
  • Different rules apply to listed buildings, flats and properties within certain protected areas for example conservation areas, areas of outstanding natural beauty or national parks.

Permitted development rights – Prior approval

  • Some permitted development rights, such as those for larger extensions or the new rights for additional storeys, require the prior approval of the local planning authority before you start any buildings works.
  • Prior approval cannot be sought retrospectively therefore it is imperative that work does not begin until the written approval of the local planning authority has been received.
  • Again, these permitted development rights do not extend to listed buildings or conservation areas, areas of outstanding natural beauty and national parks.

Changes of use/conversions

  • You may wish to consider creating more habitable accommodation by converting an existing garage to a home office, playroom or extra bedroom.
  • In many cases this will not require planning permission unless there is a restrictive planning condition on the use of the garage, it relates to a listed building or in some conservation area.


  • Permitted development rights can be removed by a local planning authority.
  • A restrictive planning condition may have been placed on the original planning consent for a dwelling (whether that’s a single dwelling or a housing estate) which removes some or all future permitted development rights or prevents a garage from being used for anything other than parking a vehicle and domestic storage.
  • Local planning authorities may also remove specific permitted development rights through an Article 4 Direction. This is more often associated with conservation areas and can include specified external alterations including changes to windows and doors, roof alterations, porches, fences and walls.
  • Exceptionally, a legal agreement may have been used to remove or restrict future developments on a site although this is likely to be relevant only to older properties.

Planning permission

  • Development which is not considered permitted development, will require planning permission. Your planning application will need to describe your proposal and include plans and drawings illustrating your proposal. It may be necessary to provide specialist reports which demonstrate the impact of your proposal on trees, ecology, parking and highway safety.

What to consider when planning your project

Understanding the potential impacts of your proposal on your surroundings and neighbours can help you to refine your plans. This could include considerations of location, layout and design.


  • Depending on your property and its location, and subject to detailed criteria, permitted development rights allow for a number of different types of extension.
  • If planning consent is required, you will need to consider matters such as the design and scale of your extension, as well as the visual impact to the character of your home and the wider area.
  • You will also need to consider the impact to neighbours, for example if there would be increased overlooking as a result of additional windows.
  • Depending on the nature of your proposal and your specific property, other planning considerations could include impact to trees, ecology and protected species, or parking requirements, for example as a result of additional bedrooms.

Home offices

  • Depending on your property and its location, and subject to detailed permitted development criteria, building a home office for yourself within your garden may not require planning permission.
  • If you are running a business from home, planning consent may be required for a change of use. This would depend on the nature of that business and the activities associated with it.
  • Where planning consent is required, you will need to consider similar issues to that of an extension, for example scale and design and impact on neighbours and trees.


  • Planning permission will be required to build an annex providing separate living accommodation in a garden.
  • Generally, annexes should be appropriate in scale and well related to the existing house, and should share some facilities with the main house.
  • There is complex case law around ancillary accommodation verses independent dwelling.

When considering your options, obtaining early planning advice will help identify which aspects of your project could be undertaken using permitted development rights and which will require planning permission.

What to consider when submitting a planning application

As well as national planning policy, your local planning authority will have specific planning policies for householder development such as extensions or outbuildings. The plans and details you submit for your application will be assessed against these policies as part of the planning application process.

It might be helpful to talk to your immediate neighbours about your plans before submitting a planning application as it will give you an opportunity to address any questions or concerns they may have at an early stage. Your neighbours will have an opportunity to comment on your proposals as part of the planning application process.

Obtaining early planning advice can help you consider the best options for the additional space you need whether that’s through exercising your permitted development rights or with a planning application. A planning consultant will carry out the necessary planning history research to identify any restrictive planning conditions on your property or in your area, and identify any local constraints. They will prepare and submit your application, liaise and negotiate with the local planning authority on your behalf. Planning consultants can also provide advice regarding lawful development certificates, for example to confirm that your proposal is permitted development, as well as providing advice on planning conditions and legal agreements.

For more information, please contact me on 023 8048 2101 or email jane.rarok@parissmith.co.uk.

To find out more on how we can help you with your planning needs visit our planning consultants and planning law page.

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