Extensions to Residential Dwellings

Building Extensions and Permitted Development

The increased size limits for single-storey rear extensions that were previously time limited and due to expire on 30 May 2019 have now been made permanent by government. Any such proposals will still be subject to the associated neighbour consultation scheme. This requires that the relevant Local Planning Authority is informed of the proposed work via a prior approval application.

A building extension is often a cost effective method of adding value and function to a home. In order to erect an extension without Planning Permission, the following should be adhered to. It should be noted that any other design concept beyond these can still be accepted within reason.

Dimensionally

It must not cover more than half of the land surrounding the original house.
It must not be higher than the highest part of the original house.
It should not extend from the rear wall by more than 3 metres on an attached house or 4 metres on a detached house.
Maximum height is 4 metres.
Should the proposal be more than one storey, it should not extend by more than 3 metres.
Where the extension is within 2 metres of a boundary, the eaves height cannot exceed 3 metres.
The eaves and ridge height should not exceed the existing house.
Two storey extensions should not be within 7 metres of the rear boundary.

Site Context

Extensions in excess of one storey, should have a roof pitch that matches the existing.
Materials should match and be ‘in keeping’ with the existing dwelling.
No verandas, balconies or raised platforms.
Obscured glazing must be applied to floors above ground level and be 1.7 metres above the floor level.

Positioning

It can not be on an elevation fronting a highway.
Side extensions can be no more than single storey with a height no more than 4 metres and no more than half the width of the original house.

Note: This information has been checked against the content on the Planning Portal Website.

Last modified: 26 August 2019.

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