Maintaining Your Property
Subsidence is a serious issue for homeowners and buyers alike. It affects the structural integrity of a property and can cause a major drop in value if it is left unchecked. Understanding what subsidence is, what causes it, how to spot it early and how to prevent it can save thousands of pounds in repairs and protect the long-term stability of your home.
Why it matters
Up to 20%
Subsidence is widely reported to knock as much as a fifth off the value of a property, and it puts off a good number of prospective buyers before they ever make an offer.
£17,264(as per the first half of 2025)
The Association of British Insurers puts the average cost of repairing subsidence at around this figure — higher again where underpinning is genuinely needed.
Two types
Active movement is ongoing and carries real financial consequences. Historic movement has stopped or been repaired and is treated far more leniently.
What is subsidence
Ground movement that is still happening and still causing problems. This is the version that matters most at the point of sale or remortgage, because a lender or buyer will want to know the cause has been identified and dealt with, not simply patched over.
Movement that has stopped, or that was repaired at some point in the past. It is considered much less of an issue, though it can still affect what a property is worth — which is why professional repairs and a structural engineer's report carry weight when you come to sell.
What causes subsidence
Clay soil shrinks, moves and cracks in hot dry weather, then expands again when it gets wet. That cycle makes the ground unstable and raises the risk of movement beneath the foundations.
Large trees and shrubs draw moisture out of the soil through their root systems, causing shrinkage and ground movement close to the building.
Leaking water washes away the soil supporting the building and weakens the foundations. It is one of the more common causes, and one of the more fixable ones.
Period properties can be at greater risk than modern ones, because older homes may sit on shallower foundations that are more prone to movement. The counterweight is that brick and lime mortar construction is more flexible and copes better with ground shifts.
Homes near quarries or old mining pits can be vulnerable, because the material used to fill the site moves as it deteriorates. Mining is one of the most common causes of subsidence in the UK.
Older properties, and those built on made-up ground, are more exposed to movement than homes on well-consolidated natural ground.
Spotting the signs
Doors and windows that catch, or no longer open and close cleanly, can be the result of walls distorting as the foundations sink or move.
Floors that slope or appear to be sinking can point to subsidence. Gaps opening up between the floor and the skirting board are worth noting too, though those more often indicate inadequate consolidation of the fill below the floor.
Wallpaper that ripples or crinkles at the joint between wall and ceiling can be a sign of movement. So can cracking where an extension meets the main property.
How to prevent subsidence
1
Keep an eye on trees and shrubs near the property. Roots spread, draw moisture from the soil and can damage drains and foundations. Avoid planting large species such as oak, elm, horse chestnut and poplar close to the house, and prune what is already there regularly so the soil does not dry out.
2
Fix leaks promptly. Escaping water erodes and moves the soil supporting the building, and a small unrepaired leak is a slow route to a much larger problem.
3
Upgrade drainage and downpipes so rainwater is carried away from the foundations rather than soaking into the ground immediately around them.
4
Watch small cracks in walls and floors and record how they change over time. Photographs with a date are more useful than memory. Changes are the early signal worth acting on.
5
Chartered surveyors and structural engineers know what to look for. A survey can pick up the warning signs and set out preventative action before the problem turns into a structural one.
Subsidence vs settlement
The Financial Ombudsman Service defines it as when the ground beneath a building sinks, pulling the foundations with it. Most home insurance policies cover subsidence, landslip and heave.
Downward movement caused by the weight of the building compressing the soil within ten years of construction — sometimes called consolidation or compaction. It is generally not covered by home insurance, which is exactly why the distinction matters.
The impact depends on the nature and severity of the damage to the foundations. Many sources suggest subsidence can knock up to 20% off a property's value and deter prospective buyers. The Association of British Insurers estimates the average repair cost at £17,264(as per the first half of 2025), rising significantly where major underpinning is required — though most homes affected by subsidence do not need underpinning at all. Buyers remain wary of properties with a history of movement, so professional repairs and certification, such as a structural engineer's report, are important when it comes to selling.
What we look at
Pattern, width, direction and location tell you far more than the presence of a crack on its own. We look at whether what we are seeing is consistent with foundation movement or with something far more ordinary.
We assess the things around the building that drive movement — proximity and species of trees, the condition of drains and gutters, where rainwater actually goes, and what the ground is likely to be doing beneath it.
The single question that changes the financial picture. We report on what the evidence supports and, where further investigation by a structural engineer is warranted, we say so plainly rather than leaving you to guess.
Common questions
Subsidence is when the ground beneath a property sinks or collapses, pulling the foundations down with it. The movement shows up as cracks in walls, uneven floors, and doors and windows that stick.
The Financial Ombudsman Service defines subsidence as the ground beneath a building sinking and pulling the foundations with it. Settlement is downward movement caused by the weight of the building compressing the soil within ten years of construction. Most insurers cover subsidence, landslip and heave, but not settlement.
Many sources suggest subsidence can reduce a property's value by up to 20%, and it deters some buyers entirely. The actual impact depends on the nature and severity of the damage to the foundations, and on whether the cause has been identified and repaired.
The Association of British Insurers estimates the average repair cost at around £17,264(as per the first half of 2025). That figure rises significantly where major underpinning work is required — though most properties affected by subsidence do not need underpinning.
No. Cracks are often caused by the building shrinking and expanding with seasonal and temperature change, by plaster drying out in a new-build or replastered room, or by an extension that was never properly bonded to the main structure. What matters is the pattern and whether it changes over time.
Large, thirsty species are the ones to be careful with near a house — oak, elm, horse chestnut and poplar among them. Their roots draw moisture from the soil, causing it to shrink, and can also damage drains and foundations directly.
Yes. Historic subsidence that has stopped or been properly repaired is treated far more leniently than active movement. Buyers are understandably wary, so professional repairs and documentation such as a structural engineer's report matter both at purchase and when you come to sell.
A survey reports on the condition of the property and flags evidence of movement, what is likely to be causing it and whether it appears active or historic. Where the findings warrant it, we recommend further investigation by a structural engineer so the cause is confirmed before you commit.
Any questions?
Our surveys are carried out by Professionally qualified surveyors and help buyers and owners identify issues like subsidence before they commit. Findings can support a renegotiation on price, help you budget for repairs, or tell you when to walk away.
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