Policy information sourced from Camden Local Plan

A5 Basements

The Council will only permit basement development where it is demonstrated to its satisfaction that the proposal would not cause harm to:

  • neighbouring properties;
  • the structural, ground, or water conditions of the area;
  • the character and amenity of the area;
  • the architectural character of the building; and
  • the significance of heritage assets.

In determining proposals for basements and other underground development, the Council will require an assessment of the scheme’s impact on drainage, flooding, groundwater conditions and structural stability in the form of a Basement Impact Assessment and where appropriate, a Basement Construction Plan.

The siting, location, scale and design of basements must have minimal impact on, and be subordinate to, the host building and property. Basement development should:

  • not comprise of more than one storey;
  • not be built under an existing basement;
  • not exceed 50% of each garden within the property;
  • be less than 1.5 times the footprint of the host building in area;
  • extend into the garden no further than 50% of the depth of the host building measured from the principal rear elevation;
  • not extend into or underneath the garden further than 50% of the depth of the garden;
  • be set back from neighbouring property boundaries where it extends beyond the footprint of the host building; and
  • avoid the loss of garden space or trees of townscape or amenity value.

Exceptions may be made on large comprehensively planned sites.

The Council will require applicants to demonstrate that proposals for basements:

  • do not harm neighbouring properties, including requiring the provision of a Basement Impact Assessment which shows that the scheme poses a risk of damage to neighbouring properties no higher than Burland Scale 1 ‘very slight’;
  • avoid adversely affecting drainage and run-off or causing other damage to the water environment;
  • avoid cumulative impacts;
  • do not harm the amenity of neighbours;
  • provide satisfactory landscaping, including adequate soil depth;
  • do not harm the appearance or setting of the property or the established character of the surrounding area;
  • protect important archaeological remains; and
  • do not prejudice the ability of the garden to support trees where they are part of the character of the area.

The Council will not permit basement schemes which include habitable rooms and other sensitive uses in areas prone to flooding.

We will generally require a Construction Management Plan for basement developments.

Given the complex nature of basement development, the Council encourages developers to offer security for expenses for basement development to adjoining neighbours.

For more information please see the Local Plan