An illustration of a back garden showing conservatory, decking, outbuilding and lawn
Mini Guide

Conservatory

Conservatories fall under the same planning regulations as any extension or addition to a house. This guide is for typical, single-storey conservatories.

Adding a conservatory to a house is considered to be permitted development, not requiring an application for planning permission, provided certain limits and conditions are met.

This mini guide offers a visual walk-through of those limits and conditions.

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1. House within designated land – Cladding and side wall

On designated land*, cladding of any part of the exterior of a dwelling (including extensions/conservatories) with stone, artificial stone, pebble dash, render, timber, plastic or tiles is not permitted development.

The regime for larger single-storey rear extensions (see point 5) does NOT apply on designated land and sites of special scientific interest.

On designated land conservatories extending beyond any side wall of the original house* are NOT permitted development.

Definitions of terms used
  • Original house - 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 - Designated land (Article 2(3)) includes national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites.
  • Principle elevation - The most visible or prominent side of a structure, typically facing a street or public area. While often considered the 'front' of the building, it may not always contain the main entrance.
1. House within designated land – Cladding and side wall

2. Area permitted

Conservatories (including previous extensions) and other buildings must not exceed 50% of the total area of land around the original house*.

Sheds and other outbuildings must be included when calculating the 50% limit.

Definitions of terms used

  • Original house - 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 - Designated land (Article 2(3)) includes national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites.
  • Principle elevation - The most visible or prominent side of a structure, typically facing a street or public area. While often considered the 'front' of the building, it may not always contain the main entrance.

2. Area permitted

3. Principle elevation or fronting highway

Conservatories cannot be built forward of the 'principal elevation'* or, where it fronts a highway, the 'side elevation.

Definitions of terms used

  • Principle elevation - The most visible or prominent side of a structure, typically facing a street or public area. While often considered the 'front' of the building, it may not always contain the main entrance.

3. Principle elevation or fronting highway

4. Side conservatory width and height

Side conservatories must be single storey and not have a width greater than half the width of the original house*, with a maximum height of four metres.

On designated land* conservatories extending beyond any side wall of the original house are NOT permitted development.


Definitions of terms used

  • Original house - 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 - Designated land (Article 2(3)) includes national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites.
  • Principle elevation - The most visible or prominent side of a structure, typically facing a street or public area. While often considered the 'front' of the building, it may not always contain the main entrance.

4. Side conservatory width and height

5. Rear conservatory depth and height

Single-storey rear conservatories must not extend beyond the rear wall of the original house* by more than four metres if a detached house; or more than three metres for any other house.

Where not in designated land* or a Site of Special Scientific Interest, this limit can be increased to eight metres if a detached house; or six metres for any other house but will require an application for prior approval.

Single-storey rear conservatory must not exceed a height of four metres.

Definitions of terms used

  • Original house - 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 - Designated land (Article 2(3)) includes national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites.
  • Principle elevation - The most visible or prominent side of a structure, typically facing a street or public area. While often considered the 'front' of the building, it may not always contain the main entrance.

5. Rear conservatory depth and height

6. Eaves and roof height

The highest part of the conservatory should be no higher than the roof ridge line of the existing house.

Maximum eaves height should be no higher than the eaves of the existing house.

If a conservatory (at the side or rear) is within two metres of a boundary, eaves should be no higher than three metres to be permitted development.

6. Eaves and roof height

Building regulations

Conservatories are normally exempt from building regulations provided they meet a number of conditions. Read further guidance on Planning Portal.

Building regulations

Further information

Details of the house type this Mini Guide applies to, where to find more guidance and access to a downloadable PDF version.

Notes and disclaimer
Important note
  • The permitted development allowances described here apply to houses, not flats, maisonettes or other buildings.  
  • You should check with your local planning authority whether permitted development rights apply – they may have been removed by what is known as an Article 4 Direction.
  • Other consents may be required if your house is listed or in a designated area.
  • When planning work, you should read all the advice on the Planning Portal under ‘Your responsibilities'. As well as other important information, you will find guidance here on the permitted development regime.
Disclaimer
  • Please note, this is an introductory guide and is not a definitive source of legal information. Read full disclaimer.  
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Planning Portal

Apply online

Before starting your project, it's important to check whether you need planning permission, building regulations approval, or both. These are separate applications, you can apply for each through the Planning Portal’s online service.

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