Planning permission in Wales

Planning legislation allows for certain works to be exempt from the need for planning permission. This is called “permitted development”. The legislation is complex and this article seeks to explain its scope in clear terms. The content does not apply to Listed Buildings; houses in Conservation Areas and to flats and maisonettes: in these cases please contact the Development Promotion Section of your Council Offices.

Adding a conservatory to your house is considered to be “permitted development”, not needing an application for planning permission, subject to the limits and conditions listed below:

• If you live in a terraced house, or in a National Park, AONB or conservation area, you are allowed to develop up to an additional 50 cubic metres, or 10% of the cubic content of your original dwelling*, whichever is greater. This is cumulative, so any previous work needs to be taken into consideration.
• For all other properties it must be less than 70 cubic metres or 15% of the cubic content of your original dwelling*, whichever is greater.
• Extensions cannot exceed 115 cubic metres under permitted development rights.
• No part of the extension should exceed the highest part of the roof of the original dwelling*.
• No more than half the area of land around the “original house”* would be covered by additions or other buildings.
• No extension should be closer to a highway than 20 metres, or closer than the original dwelling, whichever is nearer.
• The extensions should not exceed four metres in height within two metres of the boundary of the dwelling
• You should not alter any part of the roof.
• Extensions are not permitted development within the curtilage of a listed building.

Additionally, if you live within a National Park, AONB or conservation area:

• Development of an outbuilding greater than 10 cubic metres, within five metres of a dwelling, is treated as an extension.
• You should not use cladding.

* 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.

An example of where building regulation approval may be required is a Kitchen / Conservatory Extension. We suggest you contact your local council – explain your intentions – they will be able to give you more specific advice.

Further reading on planning permission and regulations can be found here.

As a further guide conservatories that require building regulation approval will need glazing of the highest insulation quality i.e. – Pilkington K Glass (low E) with argon filled units.