Planning Information: Home Extensions

Conservatory / Single Storey Rear Extension

Under the new regulations that came into force from 1 October 2008, Planning Permission would not be required subject to the following limits and conditions:-

  • No more than half the area of land around the original house* would be covered by additions or other buildings.
  • No extension forward of the principal elevation or side elevation fronting a highway.
  • No extension to be higher than the highest part of the roof.
  • Maximum depth of a single-storey rear extension of 3 metres for an attached house and 4 metres for a detached house.
  • Maximum height of a single storey rear extension of 4 metres.
  • Maximum depth of a rear extension of more than 1 storey of 3 metres including ground floor.
  • Maximum eaves height of an extension within 2 metres of a boundary of 3 metres.
  • Maximum eaves and ridge height of extension no higher than existing house.
  • Side extensions to be single storey with maximum height of 4 metres and width no more than half that of the original house.
  • Roof pitch of extensions higher than 1 storey to match existing house.
  • No verandas, balconies or raised platforms.
  • On designated land* no permitted development for rear extensions of more than 1 storey; no cladding of the exterior; no side extensions.

* 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

What this means is:-

When planning a conservatory/single storey rear extension, the key points to think about are

  • Site Coverage
    Did you know that you will need planning permission if the proposed conservatory/single storey rear extension (when taken with existing extensions, outbuildings and decking for example), will cover more than 50% of the land around your home?
  • Location
    In terms of location, if your property fronts a road and you wish to put an extension closer to that road than the principal elevation, you will need planning permission.
  • Height
    Assuming the proposal is only single storey, its maximum height can be no more than 4 metres. Interestingly, if your proposal has an eaves and ridge height greater than that of your property, you will need planning permission. Also, if you are planning on putting an extension within 2 metres of a boundary, the eaves height cannot exceed 3 metres.
  • Depth
    If you live in an attached house (say a terraced or semi-detached house for example), the maximum depth you cannot exceed is 3 metres and 4 metres in the case of detached house.
  • Veranda
    You will require planning permission if you wished to add a veranda or raised platform to the structure.
  • Cladding
    Last but not least, if your house occupies designated land, you cannot clad it. What this means is not entirely clear but we will attempt to interpret this in future articles.

Conservatory