Subsidence: What’s The Crack?


Have you noticed cracks in your walls?  Is your wallpaper crinkling at wall or ceiling joints?  Are your doors or windows sticking?  If so, then there’s a good chance your property is suffering from subsidence.

Subsidence is a major problem, affecting thousands of homes across the UK.  However, if spotted early, measures can be taken to save your home from permanent damage.

In this blog, we take a look at the tell-tale signs of subsidence, the causes and what you can do to save your home.


What is Subsidence – Root Causes

Subsidence occurs when your foundations start to sink, due to movements in the earth below your property.  The stress caused by such movement weakens the overall structure, resulting in unsightly cracks and other structural problems.


What causes the foundations to move?

The most common cause of subsidence is tree roots that have grown too close to a property’s foundations.  The roots sap water from the surrounding soil causing it dry out and shrink.  This shrinkage causes the foundations to shift and cracks to appear.

Other causes include leaky drains and soils that are susceptible to changes in weather: 

·         A leaky drain has the potential to weaken the soil around your foundations or, worse still, cause it to wash away;


·         Certain soils, such as clay soil, can dry out and shift during long periods of hot, dry weather

Subsidence as a result of clay soil is particularly common in the South-East of the UK.  Houses in this area are built on what is known as London clay, a soil type that can shrink and swell rapidly.


Spotting the Tell-Tale Signs of Subsidence

As mentioned earlier, cracks in walls is a major warning sign.  However, not all cracks are a result of subsidence –  hairline or “egg shell” type cracking can occur in dried out plaster, for example.

You may want to call upon a professional if the cracks in your walls are wider than 2mm, are diagonal and wider at one end than the other.

You should also be concerned if they appear near windows and doors and are visible internally as-well as externally.  As previously mentioned, be wary if your wallpaper is crinkling at wall or ceiling joints or your doors and windows stick when you try to open or close them.


General rule of thumb:

Keep an eye on all noticeable cracks and contact a structural engineer, such as HLN Engineering, if you start to experience any of the above problems.


Think your house has been affected by Subsidence? Act Fast!

If caught early, the effects of subsidence can be treated although you need to act fast – whilst your house may already be affected, acting early can help prevent any further damage.

Start by contacting a reputable structural engineer to survey your property and determine if subsidence is indeed occurring.  This is also important if you’re thinking of purchasing a property you think may be affected by subsidence.

If subsidence has been detected, the solution will very much depend on the cause.  For instance, if trees are the root of the problem, simply removing them could alleviate the issue altogether.  Pruning branches to limit water uptake from the ground can also work, if tree removal is not an option.

If subsidence is caused by leaky drains or a broken water main, stemming the leak at the source will do the trick.

Finally, and this is a worse-case scenario, underpinning may be the only option if your foundations have shifted significantly.  A lengthy, disruptive and costly procedure, underpinning is the process of strengthening the foundation of a structure.  This is most commonly achieved with screw piles and brackets.


Top tips for preventing subsidence

When it comes to subsidence, prevention is the best cure.  Follow these top tips to minimise the risk:

–          Avoid planting trees close to your house;

–          Regularly prune existing trees to minimise water removal form the soil;

–          Keep an eye on the drains and pipework surrounding your property, ensuring they are well maintained

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