Causes of Subsidence

Subsidence can be a costly problem to put right and is something we deal with often. As such, people are always interested to know why it has happened to them and why it seems to be so common in parts of the UK. It also flairs up at certain times of the year and under specific weather conditions. Therefore, here are some of the most common causes of subsidence.

Weather

Do you remember a few years ago there was a very dry summer where all the grass seemed to turn brown? Marc dealt with a huge increase in subsidence cases after that because droughts are a major cause of subsidence. This is due to clay based soil expanding when it gets wet and shrinking when it dries out. Normally, it does this naturally throughout the year without causing major issues but during prolonged periods of dry weather, it dries out more than it usually does and thus shrinks more and results in subsidence. Conversely, some areas with sandy or gravely soil can suffer subsidence when the soil is washed away by floods.

Trees

We all like trees on or near our property as a rule but they can sometimes be the cause of subsidence. Thirsty trees suck moisture from the soil and cause it to shrink which can result in the kind of ground movement which causes subsidence.

Water Leaks

As soil can be washed away, a broken pipe or drain leaking water can erode earth under foundations after time and make the building begin to subside.

Old Mines

Although not an issue we see a huge amount of in Sussex, it’s still a cause of subsidence in the UK. Extensive coal mining meant that lots of tunnels are left under the earth which are no longer maintained and weren’t filled in. These can eventually collapse resulting in serious issues on the surface.

Inadequate Foundations and Earthworks

It seems obvious to say that if foundations aren’t adequate for the type of building or soil, they can fail and allow a building to subside. Less obvious examples of this include things like, as Marc witnessed recently, earth supporting a building being held in place by a brick retaining wall which was beginning to fail and bow out. This caused the earth to shift and the building to subside.

All of these factors and many others can cause subsidence. Always keep your eye out for cracks which may indicate that it is beginning to happen to avoid it creating too much damage. Marc has a great deal of experience in diagnosing the cause of subsidence and advising on the best ways to deal with it. If you have any concerns regarding subsidence, don’t hesitate to get in touch on 01273 281624 or by email at info@tatesurveyingservices.co.uk.