Do You Need Planning Permission for an Extension?

by | Apr 11, 2022 | Extensions, Inspiration, Your Home

There is no denying the fact that a beautifully planned extension can transform your entire home. An extension offers the opportunity to add space, value and contemporary design –  an investment that definitely pays off.

Whatever your requirements may be, you should understand the specifications in regards to extension planning permission and extension building regulations, before starting your project.


Planning Permission or Permitted Development?

Gorgeous open plan kitchen

Planning permission gauges whether your extension plan aligns with local policies or whether it would cause unacceptable damage or impairment to the local area. Some extensions will not require planning permission, if they fall under the extension permitted development rules. 

Permitted development grants you permission to extend your property without having full planning permission – providing that your plans fall within government guidelines relating to the size and appearance of the extension. The requirements for permitted development are as follows:

  •       The extension should not take up more than half of the land  around your current home. 
  •       The height of a side extension should not exceed 4 metres.
  •       The width of a side extension cannot exceed more than 50% of the total width of the original property.
  •       A rear extension should not extend beyond the rear-end wall of the original property by 8 metres (for detached houses) or 6 metres (for semi detached and terraced properties). 
  •       If the extension is expected to be within 2 metres of the wall or boundary, the maximum height for the eaves should be 3 metres.
  •       The materials used for the extension should be similar in feel and appearance to the existing property and chimneys, balconies, verandas or any raised platforms aren’t permitted. 

If your extension plans aren’t considered to be permitted development, then you will need to apply for planning permission. The planning application process requires architectural extension drawings and an application form. It will normally take 8-10 weeks for a decision to be reached. Arkiplan can produce full architectural extension plans, submit the council application and liaise with the planning officer on your behalf (and this is all included in the quote you can get online).

Needless to say, an architectural designer can expertly advise on style and design for your extension plans, whilst keeping in line with government guidelines. 

Building Regulations for an Extension

Planning permission and building control have distinct rules and legalities and therefore, applying for one, doesn’t omit the need for the other. Building control covers the structural aspects of the proposed plan and the assessment of the build throughout the process. It is essential to obtain building regulation approval irrespective of whether or not your extension is classified as permitted development or not, so that the performance of the building can be assessed and signed off during and after construction. The given approval can be obtained via the council or paid for privately, and once signed off, states that your build is structurally viable, meets the stringent thermal performance regulations and amongst other things complies with existing fire safety rules.

The easiest way to make sure your extension plans meet all planning and building regulations, is to have your architectural designer prepare plans according to the correct procedures. They will be able to assess whether your proposed extension plans fall under permitted development or not and ensure that your project follows legislation – saving time and money in the long run. 


An architectural service such as Arkiplan will not only provide you with regulation-proof plans but will act as your agent and apply for extension planning permission and extension building control approval on your behalf.  Get started with us today.