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.
Causes of Subsidence
Subsidence poses an enormous risk to homeowners. There are a variety of reasons as to why subsidence might occur, however the most common cause is water interfering with the soil beneath the foundations.
Common Causes of Subsidence
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.