With land values soaring in recent years in some inner cities particularly London and York developers and homeowners are looking to maximise the value of their properties and building plots by going down – one or even 2 storeys below ground level. Single, double and even treble basements are not uncommon in Chelsea, Kensington and Camden. Issues affecting development which need to be carefully considered are groundwater, foundation depths, stability of the building together with adjoining or neighbouring structures and the adjacent pavement and highway.
Where a proposed development includes a new or extended basement some Local Planning Authorities provide general guidance on meeting their terms. For example Camden Development Policy 27 suggest that the following processes be addressed to establish if a full Basement impact assessment is required:
Impact of proposals on surface flow and flooding
Impact of proposals on groundwater flow
Impact of proposals on structural stability
What information should be included when submitting applications for basement developments?
When submitting applications for basement developments, the level of technical information required will vary according to the type of the development, but is likely to include:
All technical reports should be prepared by a suitably qualified chartered engineer or chartered geologist, who is a member of the relevant professional body, refer to Section 6.7 of the ARUP Camden geological, hydrogeological and hydrological study for details. Section 8 of the ARUP study sets out a list of issues that need to assessed in the report.