Hamilton Fraser Guide to Subsidence

How to minimise the risk and spot the signs

Subsidence is regarded as a property owner’s worst nightmare, often with good reason. After all, when the ground underneath a property begins to collapse, taking the building’s foundations with it, both the structural safety and the resale value of a property are obviously going to be affected.

Although rare, subsidence can be potentially devastating for any property owner, so it is important that landlords are aware of the signs and willing to take prompt action to implement preventative measures.

Fortunately, thanks to modern remedies such as underpinning, subsidence is less of a crisis than it used to be, and in many cases the causes of subsidence can be addressed and the property can be stabilised without the need for more costly structural work. But remedial works of any kind will of course incur expense, highlighting the need for landlords to make sure they are adequately insured, to ease the financial burden as well as the stress.

This article, written by NRLA Property Insurance provider, Hamilton Fraser Total Landlord Insurance, will explore how you can spot the signs of subsidence, what causes subsidence and how you can minimise the risk.

What is subsidence

Subsidence is the downward movement of the ground beneath a property, resulting in instability and reduced support underneath part or all of the foundations. Although it’s often confused with settlement, the two are quite different and it’s actually fairly easy to distinguish between them.

Subsidence refers to the downward movement of the building’s foundations that is not caused by the weight of the building, but rather by movement of the soil beneath the building’s foundations.

Settlement, on the other hand, is the downward movement of the site on which the building stands, due to the ground compacting beneath the property as the ground adjusts to accommodate the increased load. Settlement is more common in newer buildings and manifests itself in thin cracks due to changing temperatures, which cause walls to expand and contract.

Heave, meanwhile, also known as swelling, is the opposite to subsidence, resulting in an upward movement of the ground beneath the building. Similarly to subsidence, heave causes the foundations of a property to become unstable. It can occur when nearby trees are removed and the moisture previously absorbed by the tree stays in the ground, causing it to swell and ‘heave’ the property upwards.

How can you spot subsidence?

A crack in the walls of your property is not necessarily anything to worry about. Cracks are often harmless, but if they increase over time they should be investigated, particularly if they are over 15mm wide.

Top tips for spotting the signs of subsidence

• Diagonal cracks that are wider at the top than the bottom
• Cracks that appear in plaster and brickwork, particularly after long periods of hot weather, around door frames and windows, or where an extension joins the house
• Cracks that are thicker than the edge of a 10p coin (3mm wide)
• Cracks that are visible both internally and externally
• Doors and windows that are sticking and don’t fit their frames
• Ripples in the wallpaper that are not a result of damp

What causes subsidence?

Hot weather and clay soil conditions are the two factors which have the most impact on subsidence. Clay soil changes a lot dependant on the weather - when it is hot and dry it can shrink, crack and shift, making the ground unstable and resulting in a greater risk of it sinking.

Tree roots can also cause clay shrinkage, so as vegetation growing close to a building draws moisture from the soil it can also impact the ground underneath the nearby property.

UK insurers faced a surge in subsidence following the long hot summer of 2018, particularly in the South East of England, where many properties are built on subsidence-prone clay soil. The third quarter of that year saw the number of claims jump from 2,500 to 10,000, rising in value from £14 million to £64 million, an increase of 350% and the highest quarter on quarter jump since records began more than 25 years ago.

But it’s not all doom and gloom. Despite these alarming figures, even in London and the South East of England, the areas most affected, only one in 50 houses has suffered subsidence problems over the last 30 years.

Is a surge in subsidence likely?

Subsidence is difficult to predict and the two factors which have the most impact – weather and clay soil - are generally out of a landlords’ control. But taking care to make sure that your rental property is structurally sound should be your main priority as a landlord, and it will also help to minimise the risk of damage caused by subsidence.

Top tips for reducing the risk of damage cause by subsidence

• Clear gutters and down pipes and make sure drainage systems are well maintained, to prevent water leaking into the soil beneath the property
• Do not plant any trees or shrubs close to the property – make sure that they are at least 5-10 metres from the building
• Regularly prune the branches on existing trees and remove any that are too close to the property
• Investigate any cracks in the walls
• Carry out regular inspections so that you identify cracks early, particularly following hot spells
• Check the surveyor’s report for signs of subsidence before buying a buy to let property

What to do if you need to make a claim for subsidence

In the event that you need to make a claim for subsidence, you should:

• Take photos of all the damage
• Report the damage to your insurer, if you are a Hamilton Fraser Total Landlord Insurance customer you can call 0345 310 6370, who may appoint a loss adjuster or structural engineer to assess the damages
• Ensure the property is made safe. Depending on the severity of the damage, it may be necessary to prevent access to the public

What does good subsidence insurance look like?

A comprehensive landlord insurance policy such as NRLA Property Insurance provider, Hamilton Fraser Total Landlord Insurance’s policies, will cover all of the costs to repair the building. In a recent claims case, a policyholder was awarded a total of £37,000 for repairs to the porch and main building for damage caused by subsidence. In this instance the property was unsafe and the tenants had to move out. Fortunately, under their Premier policy, the policy holder was also covered for loss of rent.

The claims team at Hamilton Fraser Total Landlord Insurance points out that structural cracks can also occur as a result of movement to the property for reasons that are not classified as subsidence, for example, lateral or thermal movement, general settlement, roof spread of a property and lintel failure. These are not considered under subsidence on an insurance policy.

Siobhan O’Reilly, Property Manager at Hamilton Fraser Total Landlord Insurance, advises, “if you are looking to buy a property to rent, it’s always best to have a homebuyers survey carried out to assess the risk of subsidence so that you know what you are getting into. If the survey uncovers a subsidence issue, then we would strongly recommend commissioning a structural engineers report to understand the full extent of the problem. We also advise that you contact your insurer to understand whether they can cover the property.”

VIDEO: Q & A with Steve Barnes, Associate Director of Hamilton Fraser Total Landlord Insurance of subsidence