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Planning Permission & Building Regulations

Planning Permission for conservatories

(See also the temporary easing of size restrictions below)

From 1 October 2008 adding a conservatory to your home is considered to be a permitted development not needing an application for planning permission, subject to the following limits and conditions:

  • 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 three metres for an attached house and four metres for a detached house.
  • Maximum height of a single-storey rear extension of four metres.
  • Maximum depth of a rear extension of more than one storey of three metres including ground floor.
  • Maximum eaves height of an extension within two metres of the boundary of three metres.
  • Maximum eaves and ridge height of extension no higher than existing house.
  • Side extensions to be single storey with maximum height of four metres and width no more than half that of the original house.
  • Roof pitch of extensions higher than one storey to match existing house.
  • No verandas, balconies or raised platforms.
  • On designated land* no permitted development for rear extensions of more than one storey; no cladding of the exterior; no side extensions.
  • Where work is proposed to a listed building, listed building consent may be required.

*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.

The temporary easing of size restrictions

The limits and conditions above are the same except for increases to the size limits for single-storey rear extensions which apply between 30 May 2013 and 30 May 2016, during which period the limit is increased to 6m if an attached house and 8m if a detached house. These increased limits (between 3m and 6m and between 4m and 8m respectively) are subject to the Neighbour Consultation Scheme, details of which can be found at www.planningportal.gov.uk.

Building Regulations for conservatories

Conservatories with a 75% translucent roof and 50% glazed sides are exempt from building regulations provided that:

  1. They are built at ground level and are less than 30 square metres in floor area.
  2. The conservatory is separated from the house by external quality doors and windows.
  3. Any heating installed in the conservatory is separated from the house heating system.
  4. Glazing and any fixed electrical installations comply with the applicable building regulations requirements.

In August 2013 a document published by the Local Authority Building Control stated that solid roofed conservatories are acceptable as long as the said roof has the same thermal efficiency as that now required in a traditional new-build roof specification, with a u value of 0.18w/km2, and as long as the existing structure was not worsened in any way. This means that the existing building’s window frames and foundations have to be proved adequate to support the roof.

The solid roof and suitability of the frames and foundations requires approval under building regulations. Other elements of the design do not fall under building regulations provided that requirements 1, 2, 3 & 4 above apply.

Any new structural opening between the conservatory and the existing house will require building regulations approval, even if the conservatory itself is an exempt structure.