What are Subsidence Reports?

Tree subsidence reports identify the cause of any tree related subsidence. This includes pinpointing which tree is potentially causing the subsidence and offering recommendations.

Subsidence can be caused by clay soils, which can expand or shrink depending upon the moisture content, this is called ‘Ground heave’. This usually occurs due to the trees drawing water from the soil during a dry period of the year, which makes the soil shrink. Similarly, when the clay based soil becomes saturated it can expand. This causes the soil to either shrink or expand depending upon the conditions. As a result, the foundations of any neighbouring properties move and cracks can start to appear.

The four trees most likely to cause tree related subsidence are Oak, Ash, Poplar and Willow. In fact, an Oak can draw up around 58 gallons (219 Litres) per hour on a sunny afternoon in the summer. This is a huge amount of water, and you can clearly see why it can have a significant impact on the soil with this much water being absorbed.

The most common causes of subsidence are trees, large bushes or hedgerows. These amount to 60 % of recorded cases, with a further 15% of recorded cases being caused by drainage problems.

When would you have a Tree Subsidence Report?

There are typically three different occasions in which you would require a tree subsidence survey. The first is if you are buying a new house and there are trees in the near vicinity of the property. These trees may even be on neighbouring properties but may be close enough to cause an issue.

The second reason to commission a Tree Subsidence Survey is for insurance purposes. Often insurance companies want to mitigate their risk and there is a high chance of subsidence being caused by trees on a property, even if there is no sign of it at the present time.

The third reason is if you already have subsidence. This is evidenced by cracks in walls that are typically greater than 3mm. The size of these cracks can reduce in the winter as the soil expands, they also can grow and become quite significant when the soil shrinks, causing significant damage.

What is included in our Tree Subsidence Reports:

We would carry out an initial tree survey to the BS 5837:2012. This forms the basis of the report, identifying the tree(s) involved along with other key information;

As part of this detailed report we additionally calculate the ‘Root zone’. This is the area occupied by the actual roots of the tree.
We then calculate “Trees ‘zone of influence.’ We typically calculate this to be up to 3x the radius of the root zone.
We also typically take two soil samples and have these tested so we can analyse what the soil type is. The soil type is based on the following Soil Triangle:

Finally, we write a report with our conclusions and recommendations to mitigate the influence the tree is having on the property. Each case is individual and is influenced by the type of tree, its age and the soil type along with other physical influences.

Next Steps:

We are happy to work with a wide range of clients including home owners, insurance companies, solicitors, surveyors, local authorities and loss adjusters. Upon receiving your enquiry, we will then book one of our arboricultural consultants to complete the survey on site at a mutually convenient time.

Please give us a ring on 01782 479479 (Head office) or email us at: [email protected] and we can then get you booked in for your survey.

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Please see below for a breakdown of what you will receive upon completion of the Subsidence Report.

Please contact a member of our team to find out more information.

Tree Subsidence Reports

What are Subsidence Reports?

When would you have a Tree Subsidence Report?

Next Steps:

A digital (in the form of a PDF) pack including: