Policy information sourced from the Kensington and Chelsea Local Plan

CL7 Basements

The Council will require all basement development to:

  • not exceed a maximum of 50 per cent of each garden or open part of the site. The unaffected garden must be in a single area and where relevant should form a continuous area with other neighbouring gardens. Exceptions may be made on large sites;
  • not comprise more than one storey. Exceptions may be made on large sites;
  • not add further basement floors where there is an extant or implemented planning permission for a basement or one built through the exercise of permitted development rights;
  • not cause loss, damage or long term threat to trees of townscape or amenity value;
  • comply with the tests in national policy as they relate to the assessment of harm to the significance of heritage assets;
  • not involve excavation underneath a listed building (including vaults);
  • not introduce light wells and railings to the front or side of the property where they would seriously harm the character and appearance of the locality, particularly where they are not an established and positive feature of the local streetscape;
  • maintain and take opportunities to improve the character or appearance of the building, garden or wider area, with external elements such as light wells, roof lights, plant and means of escape being sensitively designed and discreetly sited; in the case of light wells and roof lights, also limit the impact of light pollution;
  • include a sustainable drainage system (SuDS), to be retained thereafter;
  • include a minimum of one metre of soil above any part of the basement beneath a garden;
  • ensure that traffic and construction activity do not cause unacceptable harm to pedestrian, cycle, vehicular and road safety; adversely affect bus or other transport operations (e.g. cycle hire), significantly increase traffic congestion, nor place unreasonable inconvenience on the day to day life of those living, working and visiting nearby;
  • ensure that construction impacts such as noise, vibration and dust are kept to acceptable levels for the duration of the works;
  • be designed to safeguard the structural stability of the existing building, nearby buildings and other infrastructure including London Underground tunnels and the highway;
  • be protected from sewer flooding through the installation of a suitable pumped device.

A specific policy requirement for basements is also contained in policy CE2, Flooding.

For more information please see the Kensington and Chelsea Local Plan