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What is subsidence?
The definition of subsidence is the gradual sinking of the earth’s surface beneath or around the property, which can be caused by various factors.
Most common places for subsidence to occur in the UK
The most common place for subsidence to occur in the UK is in the South-East, including, London properties which are especially renowned for being high subsidence areas. Also, islands such as the Isle of White and any coastal town in the UK.
What is the difference between subsidence, landslip, settlement, and heave?
The impact of ground movements such as subsidence, landslip, settlement, and heave on a property can be significant. If the ground movements are large enough, they can cause damage to structures on the property, as well as to the property itself.
Before we deep dive into subsidence, it is important to take a look at the types of ground movements.
Settlement
Settlement is the gradual sinking of a structure, such as a house, caused by the weight of the building or the pressure of the earth around it within ten years of construction.
Heave
Heave is the sudden, uncontrolled upward movement of earth, often caused by a burst of energy, such as an earthquake.
Landslip
Landslip is the downward movement of sloping ground. Landslips can be caused by a number of factors, including erosion, earthquakes, and landslides.
What causes subsidence?
There are many reasons why subsidence can occur. Some of the most common reasons are listed below:
- The extraction of groundwater or oil and gas can cause the ground to subside as the water or oil is removed.
- The construction of large buildings or other infrastructure can cause the ground to subside as the weight of the structure is added.
- The natural settling of the earth’s surface can also cause subsidence over time.
- The movement of water through the soil
- The drying out of the soil
- The movement of the earth’s plates
Besides the previously mentioned causes of subsidence, homes built on clay are particularly susceptible to subsidence during long, dry summers because trees and shrubs suck all the available moisture from the soil, causing buildings to shift on their foundations.
How to spot subsidence?
Spotting subsidence can be tricky to do. Often we can confuse subsidence with humidity and changes of temperature in a home that gives rise to hairline cracks.
To help you spot signs of subsidence, our expert team has prepared a list of exterior and interior signs of subsidence to help confirm your suspicions.
Exterior signs of subsidence
You may be able to see subsidence in your garden or exterior by looking for the following signs:
- Cracks in walls, floors or ceilings
- Doors and windows that are difficult to open or close
- Sticking doors and windows
- Bricks that are no longer in line with each other
- Uneven surfaces
- Dry or cracked plaster
- Gaps between skirting boards and floors
Interior signs of subsidence
It might be difficult to spot interior signs of subsidence as it can manifest itself in a variety of ways, depending on the underlying cause. However, some of the most common interior signs of subsidence include:
- Cracks in plaster or paint
- Doors and windows that are difficult to open or close
- Bowing or cracking of walls
- Sinking of the floor
- Misaligned walls or ceilings
What should I do if I spot signs of subsidence?
If you suspect that your property is suffering from subsidence, we recommend that you get in touch with a qualified surveyor to carry out a survey to determine the cause of the subsidence and further actions.
Can subsidence be prevented?
Subsidence can catch property owners off guard as subsidence can be caused by a variety of factors, many of which are outside of our control. As always, prevention is better than the cure, however, it is difficult to do with subsidence.
When able, the most common way to prevent subsidence issues is during property renovations when a homeowner can underpin the property to strengthen its foundations.
Other effective ways to prevent subsidence are to reduce the amount of groundwater pumped from an aquifer and to manage land use in a way that minimises the amount of stress placed on the ground.
How much does subsidence devalue a property?
Subsidence does not so much devalue a property as it renders a property extremely difficult to sell. Mortgage lenders will require the peril of subsidence covered as a prerequisite for a mortgage offer. If subsidence cover is not included on a building insurance policy, the mortgage lender will most likely withdraw the offer.
Our team has seen this happen on many occasions, which causes heartbreak as people lose out on their dream homes. To best avoid this pitfall, make sure you do your research on your potential purchase to understand the subsidence history.
How long of history do you have to declare subsidence for insurance?
When insuring the property, the question that is asked on the statement of fact is ‘Has your property ever suffered from subsidence, landslip or heave?’. We would strongly advise that if you are aware of a subsidence history, then you have to declare it.
That said, some insurers will not take previous subsidence history into account if the subsidence event happened more than 10 years ago. To have access to such insurance products, you need to get in touch with specialist insurance brokers like Stanhope.
Subsidence projections for the next 50 years
According to GeoClimate UKCP18 projections data illustrated below, we can expect to see an increasing number of homes in the UK affected by subsidence as well as other types of ground movements driven by climate change.
Insure your home with subsidence insurance – take advantage of our tailor-made insurance solutions by contacting our specialist insurance broker team.