While many residential extensions in London can be built under permitted development rights without a planning application, larger or more complex extensions, those in conservation areas, and those affecting listed buildings will require a formal householder planning application. Understanding how the planning system works and how to present your scheme effectively can make a significant difference to the outcome.
Planning decisions for householder extensions are made against the policies in the council local plan, the National Planning Policy Framework, and where relevant the National Design Guide. The key considerations are the impact of the extension on the character and appearance of the host property and the street, the impact on the amenity of neighbouring properties, and any specific local design guidance that applies in the area.
The application package for a householder extension typically includes existing and proposed floor plans, existing and proposed elevations of all affected faces of the building, a location plan and site plan, a design and access statement for larger or more sensitive schemes, and a planning fee. Good quality, clearly presented drawings make a positive impression on planning officers and reduce the likelihood of delays from requests for additional information.
The design of the extension must respond to the context. In conservation areas, the council will expect the design to respect the character and materials of the local area. Even outside conservation areas, an extension that is obviously out of character with the host building or the street will attract objections from neighbours and negative comments from planning officers.
Neighbour consultation is a statutory part of the planning process. The council will notify neighbours of the application and allow a comment period, typically three weeks. Objections from neighbours that raise material planning considerations, such as loss of light, overlooking, or impact on a shared driveway, will be given weight in the decision. Demonstrating in your application that you have considered these impacts and mitigated them will reduce the likelihood of successful objections.
Pre-application advice from the planning authority, discussed elsewhere, is particularly valuable for applications that are near a policy boundary or involve a sensitive site. A positive pre-application response significantly increases confidence in the outcome of the formal application.
RCB Design and Build can advise on planning applications for extensions and coordinate with planning consultants and architects where specialist input is needed.