Property subsidence assessment
Scale:PSA buildings: 1:50 000; PSA postcodes
Coverage:England & Wales
Format:PSA Buildings: GIS polygon data (ESRI, others available by request) PSA Postcode: Database csv tables
Subsidence hazards as a result of shrink–swell clay soils, inadequate foundation structures and tree presence/proximity, may lead to financial loss for anyone involved in the ownership or management of property, including developers, householders or local government. These costs could include increased insurance premiums, depressed house prices and, in some cases, require engineering works to stabilise land or property.
The BGS property subsidence assessment dataset uses a combination of best available geology, tree location and property (including age, drainage, building type and number of storeys) information to provide property- and postcode-specific information on ground movement (predominately due to shrink–swell) across England and Wales. The product enhances geological information obtained from the GeoSure insurance product and GeoSure, and includes a risk element for the housing stock at postcode and building level.
The BGS property subsidence assessment dataset identifies the risk of subsidence at property and postcode resolutions. There are two levels of data:
- BGS property subsidence assessment buildings: building-level vector GIS data with X,Y coordinates, built on OS Open Map Local, providing individual risk scores for:
- tree distance and density
- age of building (and likely foundation depth)
- potential drainage failure associated with the building
- number of storeys
- building type
- a combined hazard score
- BGS property subsidence assessment postcodes: postcode-level data, delivered as a .csv table, providing a combined hazard score for each postcode.