Do I need planning permission for my extension?

How to extend without planning permission

Permitted development rights allow you to extend your home such that most sensibly sized extensions do not need planning permission.  Local authorities have the right to make certain changes to permitted development rights so it’s best to check on your local council’s website which will spell out the rules.

If you are planning to build an extension under permitted development rights, study the criteria carefully and apply for a certificate of lawful development from your local authority which shows your extension did not require planning permission.

When you will need planning permission for your extension

Prior to submission make sure you have gone through your plans thoroughly with an architect or builder that is familiar with the local planning council and their preferences.   An application can be rejected for a minor detail which the council believes it can’t approve. When building a more ambitious extension you will need planning permission if the extension is

  • half the area of your land
  • towards a road
  • increases the overall height of the building
  • more than six meters from the rear of a semi-detached house*
  • more than eight meters from the rear of a detached house*
  • taller than four meters if a single storey
  • to the side of the property and more than half the width of the house if a single storey
  • made of materials that differ from the original style of the house
  • you plan on building a balcony or raised veranda

Single storey extensions and two storey extensions

It is more likely to get planning permission for a one-storey extension.  If permission is given for two storeys, the space doubles but the costs don’t necessarily follow.  Single storey extensions can enlarge a kitchen-diner.  This can allow daylight to flood in through roof glazing and rarely create problems.  Restrictions in a first-floor space may require a designer to be more imaginative to use space effectively.’

Side extensions

In many cases, two-storey side extensions should not be a problem, but it’s a good idea to discuss your proposals with the planners before spending money on drawing up detailed plans, especially if you are extending over two storeys. They will consider:

  • Footprint – there are few limits on the size of your extension’s floor area unless it’s likely to cover more than half the garden (including any existing extensions and outbuildings).
  • Height – it’s not normally allowed to build higher than the existing house.
  • Overlooking Features – these can be problematic if they overlook neighbours.
  • Overshadowing – building a two-storey, or higher, extension too far out may overshadow neighbours, which will limit the permissible size.
  • Highways – if the proposed extension interferes with visibility for motorists, it will limit the extension.

Open plan spaces

Open-plan living suits most people’s modern lifestyle and enhances the sense and use of space within the home.  Its sensible to think about zones within the layout, distinguishing kitchen, dining and living areas. An interior designer can help with the look, feel and definition of your space using separators, floor finishes and the like.

Building regulations for extensions

All home extensions need to comply with the building regulations, which ensure that the structure is safe.  This will require the design to incorporate a structural engineer’s calculations, submitted together with drawings as part of your building regulations application.

‘An application can be made through local authority building control, or an independent firm of approved inspectors and there are two types of application, “full plans”, or the short-cut method known as a building notice.   For a major project, it makes sense to get the design approved with full plans before works commence.