With soaring property values in many parts of London, the excavation of basements below existing houses, and incorporation of basements in new builds, has become increasingly popular over recent years.
An assessment of the effects of basement construction on the stability of neighbouring properties, along with consideration of the potential effects on groundwater movements and surface water flows, has been required by Royal Borough of Kensington & Chelsea for a number of years. More recently, London Borough of Camden has published strict requirements for the way in which basements should be assessed as part of the planning process, and these requirements have been adopted to varying degrees by neighbouring Haringey, Westminster and Barnet.
GEA has carried out a huge number of this type of assessment and our technical staff hold appropriate qualifications required by the planning authorities for carrying out the work. In areas such as Hampstead, Highgate, Camden, Chelsea, Mayfair, Knightsbidge and Holland Park we have accumulated an extensive database of ground conditions and groundwater levels and are therefore able to provide clear advice on any new basement proposal at a very early stage. Our experience also allows us to advise on the likely requirements of the planning authority through our knowledge of local precedent and to confidently advise on the likely scale of ground investigation required.
Carrying out an initial basement appraisal as part of a desk study avoids duplication of activities, such as searches of historical Ordnance Survey maps and geological maps, and allows early contact to be made with the planning authority, which can be a valuable first step on sites that are likely to be sensitive with respect to planning.