Which Trees Are Most Likely to Cause Subsidence?

Trees might seem like a harmless, green and interesting addition to any garden, but when they’re planted too close or become too big, they can cause structural damage to any neighbouring properties, including your home. If you’re thinking about planting some trees or large shrubs in the vicinity of your house, then there are some to steer clear of, no matter how far away you plant them. In this article, we’ll be explaining what subsidence is, why trees pose such a threat and which trees to look out for if you’re worried about your home falling victim to subsidence. So let’s take a closer look at the correlation between some of nature’s giants and subsidence:

What is subsidence?

Subsidence occurs when the foundations, or the ground that sits underneath your foundations, become compromised. This could be down to a number of reasons, including soil shrinkage and swelling, damaged foundations, tree roots, pooling water, clay soil and more. If you think that your home might be experiencing subsidence currently, there are plenty of signs to look out for, such as:

• Cracks around windows and doors
• Exterior cracks that run in a zig-zag pattern
• Cracks that you can fit your little finger inside of 
• Doors and windows jamming or becoming difficult to close 
• An extension coming away from the rest of the house
• Sloping floors or ceilings
• The property is noticeably leaning to one side 

There are plenty of things that can be done to prevent subsidence from occurring. They include fixing leaking drain pipes or gutters and making sure that trees and shrubs aren’t planted too close to your property. However, there are some trees that can cause subsidence issues no matter how far away they’re planted, but how? 

How can trees cause subsidence?

Trees can cause subsidence for many reasons. The first is the tree roots themselves. A tree’s root system can span out to an incredibly wide vicinity. As they grow, the tree roots will continue to creep further and further towards neighbouring structures, including your home. They’re often strong enough to penetrate brickwork and mortar lines, together with the materials used to construct your house foundations. 

As well as being able to grow wide, they can also grow deep into the ground, often surpassing your building’s foundations and into the ground that sits beneath. The next job of a tree root is to find water and nutrients, ensuring the tree will live and thrive. Where will the roots get much of that? The soil. 

As the tree roots spread, they will extract as much moisture as possible from the ground, including the soil that sits underneath your house foundations. This, in turn, causes soil shrinkage and it can be even more risky if you live in a clay soil zone. The soil shrinkage will cause movement, thus causing the structure that sits on top to move with it. This is, primarily, why trees are considered the culprits behind subsidence problems, particularly for domestic homeowners.

Which trees are most likely to cause subsidence issues?

There is a wide range of trees that can cause subsidence. The risk is increased further if they’re planted close to your property. If you’re looking to add some greenery to your garden, there are some tree species you should avoid. The following trees can be troublesome and present subsidence issues for property owners:

• Willow trees – these thrive in damp conditions and need 1,000 litres of water a day. Willow trees are notorious for extracting excessive moisture levels from the soil under your home, thus causing shrinkage. In addition, their roots can span extensive areas, putting any building at risk
• Poplar trees – with a fast growth rate and invasive roots that can penetrate any material, poplars will stop at nothing to find the moisture they need. This is the case even if they have to delve deep under your foundations
• Oak trees – oak trees can cause subsidence for much the same reasons as the previous two tree species. Growing to considerable heights and widths, the roots need to find water and nutrients from somewhere, including underneath your home
• Ash trees – a fast-growing, large tree species, the root system will spread far and wide extract moisture, making any nearby property a target

Geobear are pleased to offer sterling, non-disruptive subsidence and underpinning solutions that will stand the test of time. With the innovative geopolymer injection method, underpinning your property has never been more mess-free and time-effective. If you would like further information about how the experienced team here at Geobear can remedy instances of subsidence, then get in touch with us today – we’re always pleased to hear from you.