What Are The Main Signs of Subsidence?
Understanding the early signs of subsidence can help people take action before the situation worsens. It's a serious issue that can cause costly repairs if not addressed early.
If you have such concerns, we can undertake the necessary reporting and investigations for you, whether you choose to go through insurers or look to resolve privately. Please see the subsidence section of our website, and other blogs on the topic, where our process is explained in detail.
First of all, however, let’s get a handle on what subsidence is, why it happens. We’ll then move on to the key signs to look out for in both your home and garden.
What Is Subsidence?
Subsidence refers to the downward movement of the ground beneath a structure, which can lead to the settling or sinking of buildings and other structures.
Subsidence can be defined by Insurers in the UK as the sinking of the ground beneath a building, which pulls the property's foundations down, or causes the foundations to move down.
This can occur for various reasons, including:
Soil shrinkage
Clay soils expand when wet and shrink when dry, causing movement.
Why this can happen to small extents under normal circumstances, this seasonal movement gets progressively more in the presence of trees.
A soil moisture deficit occurs when more water is lost through evaporation and plant transpiration than is added through rainfall and irrigation. This causes the soil to dry out. Soil moisture deficits are common in the UK during spring and summer.
Monitoring soil moisture deficits can help assess the potential impact on soil health and plant development. It can also help assess the vulnerability, resilience, and drought tolerance of ecosystems.
In May 2023, soil moisture deficits across England increased due to higher temperatures and below-average rainfall. The deficits were particularly high in the western areas of England.
Tree roots
Large trees can absorb significant amounts of water from the soil, leading to shrinkage.
Where the recovery of the soil, through hydration in the winter, does not equal the shrinkage in the summer, progressive seasonal damage can occur due to a persistent soil moisture deficit.
A persistent soil moisture deficit occurs when the soil’s field capacity, or the total amount of water it can hold, is not replenished during a winter and worsens in the following summer. This is rare in the UK.
Water issues
Excessive moisture from heavy rainfall or plumbing leaks can erode soil or wash it away.
Groundworks
Nearby construction or excavation can disturb the ground and affect stability.
Natural settling
Over time, buildings can settle into the ground, especially if they were built on unstable soil such as made ground.
They could also settle due to the water issues noted above.
Early Signs of Subsidence
If you’re concerned about subsidence in your home or garden, here are some key signs to watch for:
Cracks in Walls (and Foundations)
Vertical Cracks
Look for vertical cracks in the walls, particularly those that are wider at the top than at the bottom, typically at the junctions of walls.
Vertical cracks around windows and doors may also be an indicator but, depending on the property, may just be a symptom of normal building movements.
These can indicate that the building is settling unevenly.
Cracking in render may just be due to normal thermal movement of the property so always look for any other indicators to corroborate any concerns.
Diagonal Cracks
Diagonal cracks that widen at the top or bottom can be a more serious sign of subsidence.
Cracks in the Foundation
These are harder to note as the foundation should be buried below the ground and so may only be discovered during excavations such as trial pits.
If you notice cracks in the foundation itself, this is a significant red flag. Pay attention to any cracks that are wider than 5mm.
In all instances, the cracking tends to occur suddenly, without warning. However progression of pre-existing damage may also be a sign.
Doors & Windows
Sticking Doors and Windows
If doors or windows that used to open and close easily suddenly become difficult to operate, it could be a sign that the structure is shifting.
Gaps
Look for gaps between the frames of doors and windows and the surrounding walls. If you notice gaps that weren’t there before, it’s worth investigating further.
Uneven Floors
Sloping or Bouncy Floors
If you notice that your floors feel uneven or bouncy, this could indicate that the foundation is settling unevenly.
Pay attention to any areas where the floor feels noticeably lower or higher than others.
Older properties will likely inherently have slightly bouncy or sloping floors.
Key indicators of subsidence, in this instance would be the slope accompanied by gaps under, or cracking of, the skirting boards.
Garden and Landscaping Issues
Sunken Areas:
Look for any areas in your garden that appear to be sinking or settling.
This could be due to soil erosion, settlement of backfilled areas (such as drainage trenches) or other issues related to subsidence.
Tree Health:
If you have large trees nearby, monitor their health and the condition of the soil around them.
If the soil appears to be drying out, it could be affecting the ground stability.
If the tree is showing signs of stress, it may not be drawing enough water and nutrients from the soil suggesting the underlying soil may be desiccated.
Other Potential Indicators
Pavement Cracks
If you have paved areas in your garden or driveway, look for cracks or uneven surfaces. These can be signs that the ground beneath is shifting.
This could be due to normal ground movements or the paving founded on inappropriate sub-base but could also be related to subsidence.
Water Drainage Issues
If you notice that water is pooling in certain areas of your garden, or around your home, it could indicate that the ground is settling.
This could be as a result of a drainage leak causing settlement or tree root ingress affecting (damaging) the below ground drainage.
What to Do If You Suspect Subsidence
If you notice any of these signs, it’s important to take action promptly, both so the cause can be identified and treated, and so any potential claim process is not unduly affected.
Document the Issues
Take photos and notes of any cracks or changes you observe. This documentation can be helpful if you need to consult with professionals or insurers later.
Consult a Structural Engineer
Reach out to a qualified structural engineer such as ourselves, who has significant experience with subsidence. We can assess the situation and provide expert advice on the next steps.
Monitor the Situation
Keep an eye on the signs you’ve noticed. If they worsen, whether rapidly or over time, it’s crucial to seek professional help sooner rather than later.
Consider Professional Help for Trees
If we suspect that tree roots are contributing to the problem, we will liaise with an arboricultural consultant or tree surgeon, especially if the offending tree is on private third party land or is owned by a Local Authority. They can assess the situation and recommend appropriate action.
Check for Water Issues
If you suspect that water is contributing to the subsidence, check for leaks in plumbing or drainage issues. If necessary, we will get a specialist drainage company to undertake a CCTV survey and / or check the pressure of the incoming mains. Addressing these problems can help mitigate further damage.
Conclusion
Being aware of the early signs of subsidence can save homeowners a lot of stress and potential costs down the line. By keeping an eye out for cracks, uneven floors, and changes in your garden, you can take proactive steps to address any issues before they escalate. If you notice any concerning signs, don’t hesitate to consult with a structural engineer who can provide the expertise needed to assess and address the situation.
Remember, early detection is key! If you have any more questions or need further clarification, feel free to ask. Your home is your sanctuary, and it’s important to keep it safe and sound!