Approximately 50% of homes in the UK are built on clay soil that can shrink due to the influence of tree roots. When this happens underneath building foundations, structural damage can occur. This is known as tree-related subsidence. The opposite problem of clay soil swelling after trees are removed is called ground heave and we have a separate page on this subject. Identifying if a building has moved is the job of a structural engineer. Where subsidence is suspected or identified, we can advise you on whether the damage could be tree-related and make recommendations for how to proceed. We can determine if enough evidence has been presented by the affected party to prove (on balance of probability) if trees are implicated, and if their proposed remedy is a reasonable and / or effective course of action.
For trees and subsidence issues we specialise in cases that involve defending tree owners from claims made by neighbours and other third parties who have structural damage issues. Our services in this regard can include:
- Surveying the site and recording trees which could cause or contribute to subsidence.
- Determining which recorded trees are most likely to be part of the subsidence problem.
- Identifying the risk of ground heave damage from removing trees
- Making Tree Management recommendations for mitigating property damage;
- Meeting third party tree owners to resolve conflicts where their trees are implicated in a subsidence
Please note: We do not take on cases involving:
- property owners suffering from suspected tree-related structural damage
- Property owners suffering from subsidence caused by trees owned by the local authority or highways department.
Resolving trees and subsidence issues can be particularly difficult where trees are legally protected, or owned by a third party. Tree Reports Ltd are experienced at working with property owners, engineers, local authorities and insurers to resolve subsidence and ground heave claims.
What is ground heave? Ground heave is the opposite of subsidence, and can often afflict soft soils such as clay. Typically it occurs when trees within influencing distance of a building are removed. The result is that the soil has to “re-wet” and gather moisture, which then causes the ground to swell up under building foundations, resulting in structural damage. This is a particular risk where trees are older than the damaged building. The risk of heave can rule out some tree management options, such as tree removal, especially if any tree pre-dates the building (this is because the building’s foundations accommodate the ground with the tree in it and won’t be able to properly handle any changes to the ground. Other causes of ground heave can often be related to tree roots growing into drains, resulting in excess moisture entering the ground.
An important consideration is that trees are often not the sole cause of any subsidence of heave upon a property, and that aiming to aleviate the problem by removing the suspected tree may often make matters worse.
Resolving heave issues can be much more challenging than subsidence, and therefore it is a very important consideration in mitigating subsidence claims.