What Is Tree Subsidence? Causes, Warning Signs & Solutions

Tree subsidence isn’t usually the first thing homeowners think about when they see cracks in a wall or a door that suddenly won’t shut properly but in many parts of the UK especially areas with clay-rich soils subsidence linked to nearby trees is a growing problem. Left untreated it can lead to costly repairs insurance headaches and long term damage to your property.

At Gradwell Ecology, we specialise in Tree Subsidence Reports and surveys that help you understand what’s really happening beneath your home and how to fix it in the most sustainable way. In this blog, we’ll explore what causes tree subsidence the warning signs to watch for and the solutions that work.

What Causes Tree Subsidence?

Tree subsidence happens when the ground under your property starts to shrink because nearby tree roots are sucking up moisture. It’s most common on shrinkable clay soils, which contract during dry spells. When roots from thirsty trees like oak, willow, poplar or leylandii stretch towards your foundations the soil can’t hold its structure and your building starts to move.

A few key risk factors include:

• Soil type Clay soils are the biggest culprit.
  
  
• Tree size and species Mature high water-demand trees pose more risk.
  
  
• Foundation depth Older homes often built with shallow foundations, are especially vulnerable.
  
  
• Climate change Longer hotter summers are making subsidence more common across the UK.
  
  

To put it into perspective: in the late 1980s, insurance claims for subsidence soared to around £550 million during a single hot summer up from just £70 million a few years earlier. That’s the scale of the problem when weather and tree roots collide. 

Warning Signs You Shouldn’t Ignore

Not every crack means your home is sinking but spotting subsidence early can save you a lot of stress (and money). Common warning signs include:

• Diagonal cracks in walls often wider at the top than the bottom.
  
  
• Cracks wider than 5mm especially if they keep growing.
  
  
• Doors and windows that stick or suddenly don’t close properly.
  
  
• Uneven or sloping floors inside your home.
  
  
• Gaps appearing between walls skirting boards and ceilings.
  
  

If you notice these signs, especially during or after a long dry summer it’s worth getting a professional survey to rule out tree-related subsidence.

Why Acting Quickly Matters?

A small crack might not look serious but delaying action can turn a manageable issue into a costly one. According to Building Research Establishment (BRE), cracks up to 15mm wide may be repairable without major structural work but leave them and underpinning or foundation repairs could follow.

There’s also the issue of insurance many providers are cautious about properties with ongoing subsidence and multiple claims can make premiums skyrocket or even result in cover being withdrawn. 

How Gradwell Ecology Can Help?

This is where Gradwell Ecology’s expertise makes all the difference we combine ecological knowledge with practical solutions ensuring that both your property and local biodiversity are protected. Our services include:

• Tree Subsidence Reports Detailed surveys assessing the risk from nearby trees and soils.
  
  
• Arboricultural Impact Assessments Advising developers and homeowners on how trees interact with buildings.
  
  
• Building Surveys Blending ecological and structural expertise to keep projects compliant and sustainable.
  
  

Explore more about our Tree Subsidence Reports and Arboricultural Impact Assessments.

Our aim is always to provide balanced evidence-based advice that means selective pruning installing root barriers or recommending foundation adjustments.

Solutions and Preventative Measures

Every case is different but here are some common approaches we recommend:

• Root barriers Placed between trees and foundations to limit root spread.
  
  
• Tree management Phased pruning or in some cases careful removal.
  
  
• Foundation solutions Deeper or piled foundations for new builds in clay-rich areas.
  
  
• Ongoing monitoring Especially important during dry spells.
  
  
• Regular surveys Preventative checks to identify risks before they become serious.
  
  

The best solution depends on the specific property soil type and tree species which is why an expert survey is so important.

FAQs

Q. Is every crack subsidence?

 No Many small cracks are cosmetic or seasonal. Subsidence cracks are usually wider, diagonal and keep growing.

Q. Can I just cut the tree down?

 Not always. Removing a mature tree suddenly can cause the soil to swell back making the problem worse. A phased approach is safer.

Q. Which soils are most at risk?

 Shrinkable clays like London Clay are the most problematic. Other soil types such as sand or gravel rarely cause subsidence unless drains are leaking.

Q. Will my insurance cover it?

 Some policies do but excesses are often high. Insurers may also require evidence from a professional report before approving claims.

Final Thoughts

Tree subsidence is one of those hidden problems that many homeowners don’t think about until it’s too late. The good news is with expert advice and proactive action it can be managed effectively without sacrificing your trees or your home’s stability.

At Gradwell Ecology, we’re here to help homeowners developers and businesses navigate the challenge with science-led practical solutions from tailored subsidence reports to full ecological surveys our team is ready to protect your property while respecting the environment. If you’ve noticed warning signs or simply want peace of mind, get in touch with us today.