Published 19 May 2025
How to spot subsidence in your home…
- Cracks in the walls, which are the most noticeable indicators of subsidence.
- Wallpaper that’s ripped without any signs of dampness.
- Doors and windows that don't close properly, stick unexpectedly, or close easily in winter but not in summer.
- Diagonal cracks near windows or doors, inside or outside, especially if they vary in width.
- Floors that appear to be sinking.
What is subsidence?
Damage from subsidence happens when the ground under a building sinks downward, usually due to unstable soil.
What causes subsidence?
There are four main causes of subsidence:
- Trees and other vegetation which takes moisture from the soil.
- Mining activity.
- Clay soil shrinking after long spells of dry weather.
- Leaking drains, which can wash away the subsoil below your foundations.
Is my home suffering from subsidence?
Cracks are the most obvious indicators of subsidence. Although not every crack will be a concern, pay attention to diagonal cracks that form around windows and doors - these cracks are usually wider at the top and can be hard to miss.
Cracks can appear both inside and outside and may extend past the damp proof course (DPC) down to the foundations. They often show up after long periods of dry weather.
Also, look out for wallpaper which has torn without any signs of dampness, doors and windows that don't close properly, and any signs of sinking floors.
How can you prevent subsidence?
Although there isn’t much you can do about the soil type underneath your house, there are steps you can take to reduce the risk of subsidence and avoid the need to underpin your house.
- Regularly prune trees and large shrubs near your house, like wisteria. Trees with high water needs can dry the soil up to the same height of the tree.
- For large, established trees, hire professional tree surgeons to help manage their growth. This can help avoid cutting the tree down in the future.
- Check water pipes and gutters regularly to ensure they’re not blocked or leaking. This is especially important for older homes where tree roots might grow through old clay pipes.
- Improve drainage around your home by replacing concrete or tarmac driveways and patios with more porous materials, such as gravel or grass.
How to treat subsidence
Once the subsidence has been officially confirmed on the building, there are a few things that can be done to help counteract.
-
Trees
-
Wall ties
-
Damaged pipes
-
Underpinning
-
Reconstruction
Trees
Managing mature trees near your home can be a simple solution to subsidence. In the most severe cases they can even be removed.
Wall ties
These can be used between the inner and outer walls to help strengthen the structure.
Damaged pipes
Repairing any damaged pipes can be simple fix as waterlogged soil can become easily washed away.
Underpinning
This usually done as a last resort. This process is where an additional base is added to the foundations. For more details on underpinning, check out our article on underpinning.
Reconstruction
In rare cases, this may be required where the existing structure cannot be repaired.
Does home insurance cover subsidence?
Your Allianz Home Insurance covers subsidence and heave for your property, so there’s no need to seek specialist cover.
Only a small number of houses actually suffer from subsidence, and some new homes may go through a phase known as 'settlement,' which is different from subsidence but can have some similar symptoms. Settlement occurs when the weight of the house settles into the foundations during the first few years and might cause some cracks in the plasterwork. If you’re worried, there’s no harm in getting a professional opinion.
Can you claim for subsidence on your home insurance?
If you suspect your property is suffering from subsidence, and you have home insurance with us, it's very important to let us know as soon as possible.
An expert might be sent to your property to assess the damage and decide the best course of action. This could involve monitoring the property for a period to understand how much it moves and what's causing the subsidence. As your insurer, we’ll cover the cost of the expert investigation, even if it turns out to not to be subsidence related.
We can then verify whether the damage in question is due to subsidence, and the expert will suggest what needs to be done next.
Before any repairs start, you'll need to pay the excess stated in your home insurance policy. There's typically a compulsory excess for subsidence work, which can be higher than the voluntary excess you chose when setting up your policy.
Once the work is agreed upon and the excess is paid, we’ll cover the repair costs and may also cover the cost of temporary relocation if you need to move out during the repairs.
Can you sell your home in the middle of a subsidence claim?
If you’re in the process of selling your home and need to submit a claim for subsidence damage, your insurer can transfer the claim to the new owners of the property. Once the sale has been completed, the property can be repaired. You just need to make sure you agree who has to pay the excess. The new owner can more often than not request a quote from the existing insurer.
So, make sure you look out for the signs of subsidence, and if you’re an Allianz Home Insurance customer and you’re concerned about damage to your home caused by subsidence, we’re here to help.
