Rachel Waller from Bishop & Sewell advises on this common dispute.
If you have large trees close to your property, during the recent hot weather you might have enjoyed the shade they cast, but their proximity could spell trouble, particularly if you live in London or another area with clay soil.
How does damage occur?
Clay soils, because of their structure, are able to absorb moisture, causing them to swell, and they can also give up moisture, causing shrinkage. This is typically seasonal, with expansion during the wetter winter months and shrinkage during summer. The shrinking and swelling of the soil can cause movement and damage to buildings, known as subsidence. This process can be exacerbated by the action of tress, as they take in moisture through their roots to replace the moisture that evaporates through their foliage, with most moisture being extracted during the spring and summer months when growth rates are at their highest. Some trees, such as Willows, Poplars and Oaks have higher water demands than others.
Insurance protection for homeowners
Until 2013 homeowners were not generally considered liable for damage caused in this way by tree roots because they lacked the necessary foresight. However, a decision in 2013, Khan and Khan v Harrow Council and Kane, raised doubts about that view. Most tree root subsidence disputes between neighbours are dealt with by their insurers, and where the respective insurers are signatories of the ABI Domestic Tree Root Agreement (DTRA) claims are, in practice, not brought. However, where the homeowner’s insurer is not a signatory to DTRA, or where the homeowner is not insured, the decision in Khan v Kane gives a green light to insurers to issue claims against homeowners for damage to neighbouring properties caused by tree roots, even if the homeowner was personally not aware of the risk of damage. As a result, the recent hot weather, and predicted increases in temperatures generally, could give rise to increasing numbers of such claims.
But does the decision in Khan v Kane really set a such a precedent?
Khan v Kane is fact specific, and liability in that case was established on the basis of Mr Justice Ramsey concluding that it was reasonably foreseeable to a prudent landowner that the tree-roots of a 10 meter high cypress hedge located half a meter from the Khan’s property presented a real risk of damage due to the “general risk, the location, size and condition of those trees”, including that “they dominate[d] that side of the property”. However, he also concluded that it was not reasonably foreseeable that an oak tree, a particularly thirsty species, of some 25 to 30 meters in height but located 10 meters away, presented such a risk. The oak tree did not have “any particular feature” that “would put a reasonably prudent landowner on notice”.
An issue of foreseeability
Furthermore, there is a significant difference of opinion with regard to the issue of foreseeability in Khan v Kane, and in the Court of Appeal decision in Berent v Family Mosaic Housing, 2012 WL 2500538 (2012). In Berent, the Court of Appeal upheld the lower Court’s finding that damage caused by tree roots could not have been reasonably foreseeable before the Claimant had put the Defendants on notice of the damage. It is of note that this finding was made after considering the specific knowledge that a Local Authority would have had in light of the resources available to it (i.e. not an individual landowner), and the joint experts’ view that “there is no reliable methodology for predicting precisely which trees will cause damage to which buildings” (para 35).
Therefore, it seems that claims seeking to rely on Khan v Kane should be assessed on the basis of the specific fact of those individual cases. In particular, the location of the subject tree relative to the property in question, whether the tree is a particularly thirsty species, and its overall height. In addition, the presence of other trees will likely be relevant and, per Berent, it may not be reliable to apply a level of methodology to determine risk.
Conclusion
The result of Khan v Kane is that landowners should be aware that they could be liable for damage caused by their trees, even if they themselves do not think there is any risk, and they should seek the advice of a specialist to determine any risk. If you have noticed subsidence that you think is caused by a tree on neighbouring land, or attached to a ground floor flat if you own upper floors, or if your neighbour alleges that they have suffered subsidence as a result of a tree on your land, you should seek legal advice as soon as possible.
Rachel is an Associate Solicitor in the Bishop & Sewell Dispute Resolution team.
