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Subsidence Risk and Why Insurers Assess It

Subsidence is a major problem affecting properties across the UK. It occurs when the ground underneath a building sinks, shifts, slips or heaves, causing the foundations to move and resulting in cracks and structural damage. According to the Association of British Insurers, subsidence claims cost insurers over £400 million per year.

We'll examine why subsidence occurs and why insurers take steps to assess subsidence risk when providing insurance cover.

Causes of Subsidence

There are several potential causes of subsidence in the UK:

  • Clay Soils - Much of the UK has clay-based soils which can shrink and swell according to weather conditions. Prolonged dry spells cause the clay to shrink, while excessive rain causes it to expand. This cycle of shrinking and swelling places strain on building foundations.

  • Tree Roots - Tree roots extracting moisture from the soil underneath properties is another major factor. As the roots take in water, they cause the soil to shrink.

  • Historical Mining Activity - Areas such as coalfields can be affected by the collapse of old mineshafts and tunnels. When the supporting pillars and walls deteriorate over time, the ground above sinks.

  • Broken Sewers/Pipes - Damage to underground sewers, drains or utility pipes can wash away soil, creating subsidence.

Why Insurers Assess Subsidence Risk

Due to the costs involved with subsidence claims, insurers will carry out risk assessments before providing cover. Factors they may consider include:

  • Location - Insurers are wary of areas prone to subsidence. Properties built on clay soil or former mining areas are most at risk.

  • Age of Property - Older properties with weaker foundations are more susceptible than modern homes.

  • Signs of Existing Damage - Insurers will look for cracks and other signs which may indicate ground movement.

  • Construction Type - Some house types are stronger than others. For example, compacted concrete pile foundations reduce risk.

  • Insurance Claims History - Previous claims for subsidence may make insurers reluctant to offer cover.

  • Tree Proximity - Large trees close to the property will be checked. Their roots could dry out the soil.

By carrying out these assessments, insurers can ascertain the level of risk and offer terms accordingly.

Homeowners and businesses concerned about subsidence should discuss their individual property with their insurance provider and take steps to reduce risk where possible.


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