Policy information sourced from the Lewisham Local Plan
QD9 Building alterations, extensions and basement development
Strategic Objectives:
B Housing tailored to the community with genuinely affordable homes,
F Celebrating our local identity.
A Development proposals for building alterations, extensions and basements must be designed to a high quality standard and have regard to the Council’s Alterations and Extensions SPD.
B Development proposals for building alterations and extensions will only be supported where they:
- Respect and complement the form, proportion, setting, period, architectural characteristics and detailing of the original building and the site;
- Use high quality, durable and matching or complementary materials;
- Maintain and wherever possible enhance, and do not adversely impact on, the architectural integrity of a group of buildings as a whole, or cause an incongruous element in terms of the important features of an area’s character; and
- Do not adversely impact on, or result in the loss of, the amenity of neighbouring properties, including back gardens.
C Innovative and contemporary designs will be supported where they comply with (B) above.
D Roof extensions on the street frontage of a building, particularly within predominantly residential street, should be avoided in favour of extensions to the rear of the building. Development proposals for roof extensions on the street frontage will only be supported where it is demonstrated that there is a clear design rationale, a design options appraisal has been undertaken that demonstrates an extension to the rear of building is not feasible or appropriate, and other policies are satisfied.
E Residential extensions should retain an accessible and functional private garden area which is appropriate in size in relation to building and the intended number of occupants of the dwelling.
F New units created by a residential alteration or extension must meet and, where possible, exceed the housing quality standards outlined in Policy QD8 (High quality housing design).
Basement development
G Proposals for basement development must include a Basement Impact Assessment.
H Basement development will be permitted where it can be suitably demonstrated that the development:
- Is sensitively integrated into the site, proportionate to host building (including the original building in the case of a basement extension) and avoids harm to local and historical character;
- Will not adversely impact on the structural stability of the host building, neighbouring properties, infrastructure and the public realm, taking into account local geology;
- Will not result an increase to flood risk whilst ensuring users of the development will be safe from all sources of flooding.
- Will not adversely impact on the natural environment; and e. Will not adversely impact on the amenity of neighbouring properties on occupation and use,and minimise impacts on amenity during construction.
I Proposals for residential basement development extending beneath the garden area must demonstrate that:
- There will be no loss of or harm to trees of value, including amenity and townscape value; and
- The development will maintain adequate soil depth satisfactory for landscaping, taking into account impacts on and requirements of neighbouring properties.
J Development proposals for basements including habitable rooms for housing, or other sensitive uses, must ensure safe access and egress for all likely users of the development.
Light wells
K Development proposals for light wells must respect the architectural and historical character of the host building and its wider setting, and not adversely impact on the amenity of neighbouring properties. Light wells should be sensitively integrated and designed to avoid the loss of amenity space, including garden land. Proposals that will result in an excessive or harmful loss of amenity space will be resisted.
For more information and policy context please see the Lewisham Local Plan