As mentioned previously, not all property developments require planning permission. However, it is important that you check with the local council planning department whether your planned extension requires permission, as it could be very costly if you carry out some building works which later have to be altered or even demolished because you failed to obtain the correct planning permissions. It is best to take the advice of an architect or planning consultant.

Planning Permission

The rules for when planning permission in England changed in October 2008. A complete list of the specifications is not covered within this section, however the list below can be used as general guidance.

Extension to a House

In England Planning Permission is not required as long as:

  • The proposed footprint does not exceed 50% of the total curtilage;
  • The height would not exceed the highest part of the existing roof;
  • The height of the eaves would not exceed the existing eaves height;
  • The elevation does not front a highway;
  • The maximum eaves height of the extension is less than 3m if it is within 2 metres of the boundary;
  • The proposed extension does not exceed 4m in height or have a width greater than half the width of the original house:
  • The proposed extension does not consist of –
    • the construction or provision of a veranda, balcony or raised platform;
    • the installation, alteration or replacement of microwave antenna;
    • the installation, alteration or replacement of a chimney, flue or soil and vent pipe;
    • the alteration of any part of the roof of the original dwelling house;
  • The materials used are similar to the existing house.

In Wales Planning Permission is not required as long as:

  • The proposed extension does not exceed 70 cubic metres in the case of a detached or semi detached house or 50 cubic metres in the case of a terraced house (these figures include previous extensions or additions within 5m of the original house);
  • The proposed extension does not exceed 4m in height and is within 2m of the boundary;
  • The proposed extension is not closer to any highway than the original property unless it is at least 20 metres away from such a highway. This includes any public right of way including bridle paths and footpaths;
  • Half the original amount of land surrounding the house is not coveredby additional buildings;
  • The extension is not higher than the highest point of the original house.

You should also be aware that if an Article 4 Direction has been issued in the area, or permitted development rights for your property have been removed, then planning permission will be required.
Seek Advice

For further details contact either your local council planning department, seek advice from a professional or visit the websites and links below:

General Information

The government’s Planning Portal is a great online resource for anyone who needs to know about planning permission.

Party Wall Act

Party Wall etc Act 1996

Are you affected by the Party Wall etc Act 1996? Find out the details and how to avoid any major problems with neighbours by visiting the article provided by Justin Burns BSc MRICS of Peter Barry. Read the Party Wall Act article »

Flats Extensions

Extensions to Flats and Maisonettes

Permission is required if you wish to build an extension, an outbuilding such as a garage, shed or greenhouse, as well as for any other work which would materially alter the appearance of the building. You will also need to apply for planning permission to create a hard surface such as a patio.

Building Demolition

Demolition of Buildings

Even though you may not need planning permission to demolish an existing building, you will almost certainly require permission to build on this newly available land.

Seek House Extension Advice

Always Seek Professional Advice

For further regulations affecting listed buildings or conservation areas please see the separate Listed Buildings & Conservation Areas section.

Before proceeding with any building on your property it is essential that you take time to consult either your local council’s planning department or a local architect/planner. Whereas the guidelines above apply to most situations, there may be specific local regulations that apply to your particular area of the country.

Certificates of Lawfulness

Certificates Of Lawfulness

If planning permission is not required, and the local authority, have confirmed informally that the project can go ahead then you may wish to consider submitting a certificate of lawfulness.

A Certificate of Lawfulness is similar to a planning application, but the outcome is based on fact and not on planning policy or a planning officer’s opinion.

You may wish to apply for a Certificate of Lawfulness if you want formal legal binding confirmation that your extension does not require planning permission, this can be particularly useful if you are planning to sell your house later on. An extension without planning permission will appear on the legal search and could cause problems and hold ups with your future house sale.

Certificates of Lawfulness can be made for a proposed development or made retrospectively with fees currently half that of a planning application for a proposed development and the full planning application fee for a retrospective Certificate application.

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