Causes of Subsidence

As well as water interference due to factors such as burst pipes, there are also several natural causes of subsidence including:

• Cohesive soil shrinking and swelling – Soils such as clay and silt are particularly susceptible to causing subsidence. Changes in weather cause the cohesive soils to shrink and swell leading problems within the foundations.

• Non-cohesive soils being washed away – Soils such as sand and gravel are susceptible to being washed away by water flow.

• Movement of soil structures – A combination of soil types underneath a buildings foundations can result in movement and subsidence.

• Soil decomposition – Natural soils such as peat can decompose and cause ground movement.

• Trees and other vegetation – Roots from nearby vegetation can absorb moisture from the soil, causing it to shrink. This is more common in dryer conditions where plants expand their roots in search of water.

Man-made Causes of Subsidence

• Damaged drains – Water from damaged drains can saturate and even wash away the soil beneath foundations. This is common in sandy or gravelly soils.

• Mine shafts – Open areas underneath the ground can lead to subsidence.

• Nearby traffic – Vibration from traffic can cause soil movement.

• Improper ground preparation – Inadequate preparation during the planning stages of construction can lead to a variety of problems including subsidence.

• Construction work – Nearby construction work can cause vibrations leading to movement of the soil underneath buildings.