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Subsidence: A Growing Threat to UK Properties

Lucion GroupLucion Group

Lucion Group

17th May, 2024

Subsidence, the gradual sinking or downward settling of the ground beneath a building, poses a significant threat to properties across the United Kingdom. As climate change continues to impact our environment, the risks of subsidence are only increasing, with an estimated 1.2 million additional homes expected to be at risk by 2050, according to a recent article in The Telegraph.

In this blog, Lucion Surveying & Geospatial Director Will Vennard explores the causes and consequences of subsidence, who is responsible for monitoring it, and how our team can help mitigate this growing problem.

What is Subsidence?

Subsidence occurs when the ground beneath a building begins to sink or collapse, disrupting the foundation and causing structural damage to the property above. This can manifest in various ways, such as cracks in walls, uneven floors, and misaligned doors and windows.

Subsidence is often caused by a combination of factors, including:

  1. Soil composition: Cohesive soils like clay are particularly susceptible to shrinking and swelling with changes in moisture content.
  2. Tree roots: Thirsty trees and shrubs can draw moisture from the soil, leading to shrinkage and instability.
  3. Leaking pipes: Damaged water pipes can wash away soil, creating voids and destabilising the ground.
  4. Mining activity: Properties built near old mine shafts may be at risk of subsidence due to the collapse of underground cavities.
  5. Construction Works: Excavations, vibration from construction machinery and equipment, groundworks and poor preparation before works commencing can cause subsidence to your property

The Impact of Subsidence on Asset Depreciation

Subsidence can have a significant impact on a property’s value, with some estimates suggesting that affected homes could lose up to 20% of their market value.

In addition to the direct costs of repairs, which can range from £5,000 to £50,000 or more, subsidence can also make a property more difficult to sell or insure. This is particularly concerning for homeowners, investors, and mortgage lenders, who may face substantial financial losses if subsidence is not properly addressed.

Who is Responsible for Monitoring Subsidence?

Under UK law, property owners have a legal duty to ensure that their buildings are safe and structurally sound. This includes monitoring for signs of subsidence and taking appropriate action to address any issues that arise. However, many property owners may not have the expertise or resources to effectively monitor for subsidence on their own.

Local authorities also have a role to play in monitoring subsidence, particularly in areas with a history of mining activity or other known risk factors. The Coal Authority, for example, maintains a database of coal mining reports and offers a subsidence claims service for properties affected by mining-related subsidence.

In addition, the Building Research Establishment (BRE) provides guidance and best practices for managing subsidence risk in both new and existing buildings. The Institution of Structural Engineers (IStructE) also offers resources and training for professionals involved in subsidence assessment and remediation.

The Costs of Getting it Wrong

Failure to properly monitor and address subsidence can have serious consequences for property owners, occupants, and the wider community. In addition to the direct costs of repairs and depreciation, subsidence can also pose safety risks if left unchecked.

In extreme cases, buildings may become uninhabitable or even collapse, putting lives at risk.

Moreover, subsidence can also have broader economic impacts, particularly in areas with a high concentration of affected properties. This can lead to reduced property values, decreased tax revenues, and a strain on local services and infrastructure.

Subsidence Solutions Provider

When it comes to protecting your property from the damaging effects of subsidence, building-level monitoring is a powerful tool that provides you with comprehensive data and insights. Unlike crack monitoring, building-level monitoring offers precise measurements of your foundation’s movement, revealing not only how much it is moving but also when and why these changes occur.

At Lucion, we understand the importance of accuracy and reliability in level monitoring. That’s why we strictly adhere to the guidelines outlined in BRE Digest 386, utilising state-of-the-art Topcon optical instruments that boast an impressive accuracy of up to 0.1mm. Our experienced team carefully places evenly spaced points on your building, typically around 300mm above ground level, and establishes a datum point in a stable area near the monitored structure.

As your building moves, these fixed points move with it, allowing us to track and measure any changes concerning the datum point. We take readings every 4-8 weeks over 6-12 months, ensuring you have a clear and comprehensive picture of your property’s subsidence over time.

By comparing the readings against the datum, we can provide you with accurate measurements of the subsidence affecting your property. This invaluable information empowers you to make informed decisions about the best course of action to protect your investment and ensure the safety of your building and its occupants.

With our level monitoring services, you can have peace of mind knowing that you have access to the most precise and reliable data available. Trust Lucion to help you navigate the challenges of subsidence and safeguard your property for years to come.

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