Policy information sourced from the Hillingdon Local Plan: Part 2
DMHD 3: Basement Development
When determining proposals for basement and other underground development, the Council require an assessment of the scheme’s impact on drainage, flooding, groundwater conditions and structural stability. The Council will only permit basement and other underground development that does not cause harm to the built and natural environment and local amenity and does not result in flooding or ground instability. Developers will be required to demonstrate by methodologies appropriate to the site that their proposals:
- avoid adversely affecting drainage and run-off or causing other damage to the water environment;
- avoid cumulative impacts upon structural stability or the water environment in the local area;
Schemes should ensure that they:
- do not harm the amenity of neighbours;
- do not lead to the loss of trees of townscape or amenity value;
- do 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, for example through the introduction of front lightwells; and
- do protect important archaeological remains.
The Council will not permit basement schemes which include habitable rooms and other sensitive uses in areas prone to flooding.
The Council will not permit basement schemes in Listed Buildings and will not permit them in Conservation Area locations where their introduction would harm the special architectural or historic character of the area.
For more information please see the Local Plan: Part 2