Geotechnical and
Environmental Services

Specialists in the investigation, assessment and reclamation
of development land.

Subsidence Investigations

If new cracks appear in your building then seek expert help from BRD. Working in partnership with your building surveyor or structural engineer / insurance company we can identify the cause of the building movement and more importantly the best solution.

Subsidence is the generic term for building damage caused by ground movements and can be caused by a variety of factors, such as:

  • As clay soils dry out they shrink causing downward ground movement i.e. subsidence.  This occurs naturally with seasonal weather variation, but can be exacerbated by trees and other vegetation. If foundations are not deep enough then the shrinking soils can damage building foundations.
  • Just as clay soils shrink when dried, they swell with added moisture which is known as soil ‘heave’. This can be triggered by cutting down trees or leaking water pipes/drains.
  • Mining activity can lead to subsidence as collapse of historic workings at depth migrate voids upwards to near the surface.
  • Some rocks, such as Chalk, can be susceptible to be dissolved by slightly acidic water leaving buried voids which in turn collapse. In areas prone to such movements this type of subsidence can be caused by leaking drains.

BRD can help identify the cause of the subsidence by studying the local geology and undertaking targeted ground investigations.  These typically involve excavation by hand to expose foundations and narrow diameter boreholes. The benefit of hand held or small tracked borehole rigs is that they can access existing garden areas without causing too much damage.

Often such works are undertaken in consultation with a building surveyor/structural engineer with BRD identifying the cause of the ground movement and then helping the surveyor/engineer develop plans for remedial repairs to the structure.