4th Floor
Silverstream House
45 Fitzroy Street
London
W1T 6EB
Silverstream House
45 Fitzroy Street
London
W1T 6EB
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4th Floor, Silverstream House, 45 Fitzroy Street, London, W1T 6EB
E: info@kelpstudio.co.uk
T: 020 3835 2633
M: 07561 417319
Subsidence, heave or settlement? How to tell the difference
23 October 2026 · Blog
When a house moves, people often call it subsidence. But engineers separate ground movement into three types, and the difference matters: each has different causes and fixes, and insurers treat them differently.
Subsidence: the ground drops away
Subsidence is when the ground under the foundations moves downwards. Common causes in the south east are:
• Clay soils shrinking as they dry out, often made worse by nearby trees and shrubs drawing moisture from the ground.
• Leaking drains washing out or softening the soil under the foundations.
• Old mine workings or soft ground, which are less common in our area.
Cracks are often wider at the top, run diagonally from the corners of windows and doors, and can open in dry summers and close again in wet winters.
Heave: the ground swells
Heave is the opposite. Clay soil takes on water and expands, pushing the foundations upwards. It often follows the removal of a large tree, as the ground slowly rehydrates over several years. Cracks from heave tend to be wider at the bottom.
Settlement: the building beds in
Settlement is the ground compressing under the weight of a new building or extension. It usually happens in the first few years, then stops. Small cracks where an extension meets the original house are common and often stable. Settlement is generally not covered by home insurance.
Why the difference matters
Subsidence and heave are often covered by home insurance, while settlement usually isn’t, so check your policy and report suspected subsidence to your insurer. The fix also depends on the cause: repairing a leaking drain, managing a tree, monitoring the cracks, or in more serious cases, underpinning. Getting the cause right first avoids spending money on the wrong repair.
How we can help
We inspect the cracks, look at the soil, trees and drains around the property, and tell you which type of movement is most likely and what to do next: no action, monitoring, repair or further investigation.
Guide prices: specific inspection £950 + VAT, general inspection approx. £1,700 + VAT. We can usually visit within 3 working days.
Our subsidence and crack reports →
Is this crack serious? →
Book an inspection or call 020 3835 2633
Settlement is the ground compressing under the weight of a new building or extension. It usually happens in the first few years, then stops. Small cracks where an extension meets the original house are common and often stable. Settlement is generally not covered by home insurance.
Why the difference matters
Subsidence and heave are often covered by home insurance, while settlement usually isn’t, so check your policy and report suspected subsidence to your insurer. The fix also depends on the cause: repairing a leaking drain, managing a tree, monitoring the cracks, or in more serious cases, underpinning. Getting the cause right first avoids spending money on the wrong repair.
How we can help
We inspect the cracks, look at the soil, trees and drains around the property, and tell you which type of movement is most likely and what to do next: no action, monitoring, repair or further investigation.
Guide prices: specific inspection £950 + VAT, general inspection approx. £1,700 + VAT. We can usually visit within 3 working days.
Our subsidence and crack reports →
Is this crack serious? →
Book an inspection or call 020 3835 2633