With tree-related insurance claims, explains NFU Mutual senior underwriter Ian Perry, subsidence often lies at the root of the problem.

Ian has worked in NFU Mutual’s underwriting team for more than six years.

He’s an expert in household buildings and contents insurance, especially when it comes to protecting customers from the perils of unpredictable weather.

So he often finds himself dealing with one of the main risks inherent in having trees on your property: subsidence.

“There are many misconceptions about what subsidence is,” he says. “What some people believe is subsidence caused by trees is actually the result of some other problem, like a flaw in the structural integrity of the house.”

So how do you know if your subsidence is caused by the trees on your land? Geography is the biggest clue, explains Martin.

“If you were to draw a line from Bristol in the West to The Wash in the East, then properties located to the South and East of that line are theoretically more vulnerable to tree subsidence, because of the predominance of clay soil.”

Despite the wide geographical area, there are only three main tree types which cause the greatest risk of subsidence. These are Willows, Poplars and Oaks which all have roots that grow laterally, and therefore can extend underneath buildings during the growing season, particularly when the summer is dry as opposed to other trees which have roots that tend to extend down into the ground, in search of water.

Usually there’s only one way to fix the problem following an insurance claim: removing the tree that caused the subsidence in the first place. Other options are available as well though.

Managing subsidence

Ian explains the options available for dealing with problematic trees.

“Subsidence is when a property ‘sinks’ due to a breakdown or loss of soil beneath it. The first sign of possible subsidence is usually cracks in the structure of the building, and a tell-tale sign is when the crack is wider at the top than at the bottom.

“If your tree is over 10 metres high, it needs to be at least 10 metres away from the building, and even further in the case of Willows, Poplars and Oaks. In certain circumstances, trees can’t be removed though and may be subject to what’s known as a tree preservation order. If that’s the case then we advise a root barrier together with a very strict maintenance regime for that particular tree.”