Planning Permission: A Complete Guide to Common Projects

When you need it, when you don’t need it, what are your permitted development rights and how to appeal a planning decision. We’ve got it here!

When Do I Need Planning Permission?

You will probably need planning permission if you are doing 1 or more of the following:

  • Building something new

  • Making a major change to an existing building e.g. Extensions etc.

  • Or if you are changing the use of a building

This article will cover the most common examples of when planning permission is and is not needed.

Do I Need Planning Permission for an Extension?

You will only need planning permission for an extension if it doesn’t adhere to permitted development rights.

You will need it if:

  • Your extension is 2-story and extends more than 3 meters from the original rear wall of the house.

  • Your 2-story extension is no closer to 7m to the rear boundary of the house.

  • Your single story extension is more than 8 meters (if your house is detached) or 6 meters (for any other type of house). The maximum height for a single storey extension can only be 4 meters or less.

  • Your single story side extension is not higher than 4m and the width is no more than half of the original house.

  • Your extension is not higher than the highest part of the roof.

  • Materials you are using are similar to that used in the rest of the house.

As you can see, in many cases these conditions are not likely to be met as we seek to make the most of our spaces. Read here for more a more detailed view of extensions and if you need planning or not.

Do I Need Planning Permission for a Garage Conversion?

Usually no. If your garage is attached to your house and you are not changing the exterior dimensions then it will fall under permitted development rights.

You will need planning permission if:

  • You intend to turn your garage into a separate house (no matter who intends to live in it).

  • Change of use - e.g. Outbuilding to Annexe

  • Sometimes permitted development may have been removed e.g. if you live on a new housing estate or in a conservation area.

  • You change the dimensions of the building.

Need some ideas for your garage conversion? Check out our garage conversion ideas to help get your project started.

Do I Need Planning Permission for a Conservatory?

Adding a conservatory to your house is deemed to be within permitted development rights, subject to the standard limits and conditions that apply to extensions on houses.

Do I Need Planning Permission for Outbuildings?


Thinking of erecting a shed, summer house or something along those lines?

Rules governing outbuildings apply to sheds, playhouses, greenhouses and garages as well as other ancillary garden buildings such as swimming pools, ponds, sauna cabins, kennels, enclosures (including tennis courts) and many other kinds of structure for a purpose incidental to the enjoyment of the dwelling house.

You will need planning permission if your project does not fall within the limits and conditions below:

  • Outbuildings (including garages) overall height cannot be greater than 4 meters with a dual pitched roof, or 3 meters for any other roof. The heigh to the eaves cannot be greater than 2.5m.

  • If the building is within 2 meters of a boundary then the maximum height of the building can only be 2.5m.

  • No verandas, balconies or raised platforms (a platform must not exceed 0.3 metres in height)

  • No more than half the area of land around the original house* would be taken up by the new building (and existing out buildings)

  • In National Parks, the Broads, Areas of Outstanding Natural Beauty and World Heritage Sites the maximum area to be covered by buildings, enclosures, containers and pools more than 20 metres from the house to be limited to 10 square metres.

  • On designated land** buildings, enclosures, containers and pools at the side of properties will require planning permission.

  • If you live in a listed building, any outbuilding will require planning permission.

*The term "original house" means the house as it was first built or as it stood on 1 July 1948 (if it was built before that date). Although you may not have built an extension to the house, a previous owner may have done so.

**Designated land includes national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites.

Do I Need Planning Permission for Internal Building Work?

You should not need to apply for planning permission for internal alterations including building or removing an internal wall.

If you live in a listed building, however, you will need listed building consent for any significant works whether internal or external.