Policy information sourced from Hammersmith & Fulham Local Plan

DC11 BASEMENTS AND LIGHTWELLS

New basements and extensions to existing basements will only be permitted where they:

  • do not extend into or underneath the garden further than 50% of the depth of the host building measured from the principal rear elevation;
  • do not extend into or underneath the garden further than 50% of the depth of the garden;
  • are set back from neighbouring property boundaries where it extends beyond the footprint of the host building;
  • do not comprise more than one storey. Exceptions may be made on large sites;
  • do not result in an unacceptable impact on the amenity of adjoining properties or on the local, natural and historic environment during and post construction;
  • are designed to minimise the risk of flooding to the property and nearby properties from all sources of flooding;
  • include a minimum of one metre of soil above any part of the basement beneath a garden;
  • ensure that the basement helps reduce the volume and flow of surface water run-off through appropriate use of SuDS and will provide active drainage devices to minimise the risk of sewer flooding;
  • ensure that lightwells at the front or side of the property are as discreet as possible and allow the scale, character and appearance of the property, street or terrace to remain largely unchanged;
  • are designed to safeguard the structural stability of the existing building, nearby buildings and other infrastructure;
  • provide a Construction Method Statement (CMS) (carried out by a qualified structural or civil engineer) to be submitted with planning applications for all basement projects; and
  • provide a construction traffic management plan as part of the CMS to ensure that traffic and construction activity does not cause unacceptable harm to pedestrian, cycle, vehicular and road safety.

New self contained basement flats will not be permitted in the Environment Agency’s Flood Zone 3 areas where there is a risk of rapid inundation by flood waters in the event of a breach of the river’s flood defences, unless a satisfactory means of escape can be provided.

For more information please see the Local Plan