Chimney against blue sky


Dealing with Subsidence

The merest hint of subsidence can see panic set in amongst homeowners – the expense and upheaval it can cause is well-documented.

Here we look at some of the reasons for subsidence, how to identify it and ways in which you can deal with the problem. 

What exactly is subsidence?

Subsidence is essentially the downward movement of earth. The ground beneath us is constantly moving, but significant problems arise when earth below a property is moving at an uneven rate.

Identifying subsidence

Subsidence can be difficult to diagnose, as most of the tell-tale signs could quite easily be caused by other factors.

The most common indication that you may have a subsidence issue is the appearance of fresh cracks in plaster work– or the expansion of existing ones. Small cracks are fairly common in new-build homes however, so fears of subsidence may well be unfounded.

Other indicators could be cracks in your exterior brick work, or doors which start to ‘stick’ for no apparent reason. Look for alternative explanations – if you can’t find any, err on the side of caution and bring in an expert.

Chartered surveyors should be able to identify a subsidence problem, while structural engineers may also be required.

Even with professional help, a definite diagnosis can take months. You may need to monitor (and measure) the cracks for as much as a year before the picture becomes entirely clear.

Why does subsidence occur?

Subsidence is usually caused by factors outside the homeowners’ control – but not always.

Seemingly harmless practices, such as planting a tree too close to your property, can be to blame.

Trees and other plants draw moisture from the soil, causing the soil to shrink. When in desperate need of water, plants may extend their roots under your property – and it’s then that problems can arise.

Other causes can be leaking drains that damage the ground beneath your home, or simply dry clay soil that shrinks due to its low moisture content. 

Dealing with subsidence

Identifying the cause of subsidence is the first step to its solution. If thirsty tree roots are to blame, removing the tree (or pruning it) may be enough to help stabilise your home.

Similarly, if drainage is at fault, repairs to the damaged pipe work could provide the remedy.

If subsidence has taken hold more significantly, underpinning may be required. Underpinning is an expensive, drawn out procedure to stabilise the foundations of a property, but is fortunately required in only a quarter of all subsidence cases.