What is the difference between subsidence, settlement and heave?
Subsidence, settlement and heave all describe ground movement — but they are not the same thing.
Understanding the difference is important. Each has different causes, different risk levels, and different solutions.
In simple terms:
- Subsidence = the ground moves down
- Settlement = the building compresses into the ground
- Heave = the ground pushes up
Let’s break that down clearly.
If you’re unsure what subsidence is in general, start with our guide: What is subsidence?
What is subsidence?
Subsidence is the downward movement of ground beneath foundations.
It usually happens because:
- Clay soil shrinks during dry weather
- Trees remove moisture from the soil
- Drains leak and wash away fine particles
- Ground defects or voids develop
When one part of the foundation moves more than another, the building can crack.
Common signs include:
- Diagonal stepped cracks
- Doors and windows sticking
- Gaps forming internally
Subsidence often requires investigation to determine whether movement is ongoing.
Learn more here: Signs of subsidence
What is settlement?
Settlement is the natural compression of soil under a building’s weight.
It usually:
- Happens within the first few years after construction
- Is vertical and uniform
- Slows down and stops
- Does not continue indefinitely
Almost all buildings settle slightly after they’re built. This is normal.
When is settlement a concern?
Settlement becomes problematic if:
- It is uneven (differential settlement)
- It continues long after construction
- It causes widening cracks
Most older properties have already completed settlement.
What is heave?
Heave is the upward movement of the ground beneath foundations.
It is effectively the opposite of subsidence.
Heave typically occurs when:
- Trees are removed from clay soil
- Clay rehydrates and expands
- Moisture levels increase significantly
Instead of foundations dropping, they are pushed upward.
Why clay soil matters in the UK
The UK has large areas of shrinkable clay.
Clay soil:
- Expands when wet
- Shrinks when dry
- Moves seasonally
This seasonal cycle is why subsidence and heave are often linked to weather patterns.
Settlement, however, is unrelated to seasonal moisture — it’s about initial ground compression.
Key differences at a glance
|
Type of movement |
Direction |
Typical cause |
Ongoing? |
Common in UK? |
|
Subsidence |
Downward |
Clay shrinkage, drains, trees |
Can be |
Yes |
|
Settlement |
Downward |
Initial soil compression |
Usually stops |
Yes |
|
Heave |
Upward |
Clay rehydration, tree removal |
Can be |
Yes (clay areas) |
How can you tell which one is affecting your home?
The pattern and timing of cracks often provide clues.
Subsidence indicators:
- Cracks after dry summer
- Diagonal stepped cracking
- One side of building affected
Settlement indicators:
- Property is relatively new
- Vertical hairline cracks
- Movement stabilises
Heave indicators:
- Occurs after tree removal
- Upward floor movement
- Doors binding at top
However, visual signs alone are not enough for diagnosis.
Learn more here: How is subsidence diagnosed?
Yes.
If a large tree near a property is removed without professional assessment, clay soil can rehydrate and expand — causing heave.
This is why tree removal should always be carefully managed.
Usually not.
If settlement is historic and stable, no structural intervention is needed.
Monitoring may be recommended if there’s uncertainty.
No.
Traditional underpinning is sometimes used, but modern ground improvement techniques can:
- Strengthen soil
- Stabilise foundations
- Avoid excavation
- Reduce disruption
You should consider professional assessment if:
- Cracks are widening
- Movement is seasonal but worsening
- Doors and windows distort suddenly
- Tree removal has recently occurred
Understanding the type of ground movement prevents unnecessary work — and unnecessary stress.
Get in touch
If you have a subsidence issue and would like a free assessment, plese get in touch.
