What is Subsidence?

Subsidence refers to the gradual downward settling (or sinking) of a building’s foundation, often resulting from shifts in the underlying soil. If left unaddressed, subsidence can manifest in a range of structural issues, including uneven floors and wall cracks, and may even compromise the building’s overall structural integrity.

It is typically triggered by changes in the soil composition beneath the property, such as the contraction of clay soil or the depletion of ground moisture by tree roots.

Should I care about subsidence?

Being aware of the risks associated with subsidence is crucial for making an informed decision when you’re in the market for your first home. It isn’t merely a geological issue; it carries tangible consequences for homeowners. Subsidence can substantially reduce your property’s value, it can also make your home unsafe to live in.

What are the signs and symptoms of subsidence?

Recognising the signs of subsidence early on can save you from future headaches. Here are some common indicators:

Internal Signs

• Cracks in foundations, floors, walls, ceilings of buildings: These usually start small and get wider over time as subsidence continues. The cracks may be diagonal, horizontal, or vertical and often taper from top to bottom.
• Sagging floors, separation of walls from ceilings, or door frames out of alignment: Changes in floor levels can also indicate subsidence.
• Doors and windows that stick or jam: This occurs when the building structure shifts due to uneven sinking of the ground.
• Unexplained ripples in wallpaper not caused by dampness: This could be a subtle indication of underlying issues.

External Signs

• Cracks in the brickwork, particularly near windows and doors: These can be a red flag and should be taken seriously.
• Cracks or bumps in patios, roads, pavements: Subsidence can cause buckling, sagging, or the development of depressions. Cracks often form along edges or weak spots.
• Leaning telephone poles, trees, or walls: Uneven ground settlement can make vertical structures tilt to one side.
• Sunken or lower spots visible in the garden: These depressions indicate localized sinking and are more apparent after rainfall.

Additional signs

• Gaps where walls meet floors, cracks in patios, leaning fences, and changes in the soil condition around the property.
• Survey reports may also highlight potential subsidence issues

What are the Causes of Subsidence?

Subsidence can be triggered by a myriad of factors, each requiring its own specific treatment. Here’s a look at the known causes:

Soil -related causes

• Clay Soils: These types of soils are prone to shrinking, cracking, and shifting, especially during dry weather, which can result in foundational movement.
• Loose or Sandy Soils: Such soils are inherently unstable and can easily shift, particularly if disturbed.

Vegetation and Trees

• Tree Roots: Large, mature trees can absorb significant amounts of water from the soil, causing it to contract.
• Planting Trees Too Close to Property: While young trees may not pose an immediate threat, they can become problematic as they grow.

Water -Related Causes

• Leaking Drains and Pipelines: Excessive water from leaks can soften the soil, leading to its compression under the weight of the building.
• Drained Lakes or Reservoirs: When large bodies of water are drained, the ground may sink due to the loss of water pressure support.

Building Related causes

• Inadequate Foundation Depth: Poor construction practices may result in shallow or weak foundations, unable to support the building adequately.
• Aging Infrastructure: Over time, building materials can deteriorate, and older foundations may not meet current construction standards, contributing tosubsidence

Human Activities

• Mining: The collapse or compression of old mining tunnels can cause the ground above to sink.
• Nearby Construction: The use of heavy machinery and excavation can disrupt the soil’s stability.
• Agricultural Activity: Large-scale farming activities, such as Irrigation and Water Extraction can affect the stability of the ground.
• Vibration: Ongoing vibrations from heavy traffic, trains, or industrial activities can contribute to soil movement.

Natural Factors

• Freezing and Thawing: This cycle can cause the soil to shift, affecting the building’s stability.
• Earthquakes: Seismic activities can destabilise the ground.
• Land Slips: These are often triggered by a combination of gravity and water saturation, causing layers of earth to slide downhill.

Addressing each of these causes often involves a multi-disciplinary team of experts, including engineers, surveyors, and contractors, to diagnose and remediate the issue comprehensively.

What to do if you suspect subsidence: Tips for First-Time buyers

1. Ask Questions: Don’t hesitate to ask sellers or estate agents about any history of subsidence.
2. Seek Expert Opinion: Before making a purchase, consider hiring a chartered surveyor to assess the property for subsidence risks. They can offer a detailed report and solutions for treatment.
3. Get Repair Estimates: Get estimates for potential repairs like underpinning, which could be very expensive.
4. Get Legal Advice: Engage a solicitor to guide you through the legalities of buying a property with subsidence. Consider adding protective clauses to your offer in case future issues arise.
5. Mortgage Concerns: Consult with mortgage providers, as they may be reluctant to approve loans for properties with subsidence.
6. Get home insurance quotes: Securing insurance for a property with subsidence history can be costly or challenging. Investigate this before making any decisions.
7. Consider resale Value: Keep in mind that even after you’ve addressed subsidence issues, the property may have a lower resale value.
8. Monitor: Even after purchase, keep an eye on your property for any signs of subsidence.

Key Takeaways 📚

1. Subsidence is the gradual sinking of a building’s foundation due to shifts in the underlying soil, leading to structural issues like cracks and uneven floors.
2. Early signs of subsidence include cracks in walls and foundations, sticking doors and windows, and visible changes in the garden or surrounding area.
3. Various factors can trigger subsidence, such as soil composition, tree roots, water leaks, and human activities like mining and construction.
4. Addressing subsidence often involves a multi-disciplinary team of experts and can be costly, impacting both the property’s market value and insurability.
5. Before buying a property, it’s crucial to consult experts like chartered surveyors, get repair estimates, and consider the implications for mortgages and insurance.