What causes subsidence?
An enormous problem for homeowners, ground subsidence can strike anywhere for a variety of different reasons. Potential building and home buyers should be aware of the possible causes of subsidence to help them avoid problems in the future.
Often subsidence is related to the moisture content of the soil underneath the foundations. Certain soil types are more susceptible than others. However, there are several man-made factors that have an impact, too.
Natural Causes of Subsidence
- Cohesive soils shrinking and swelling.
Cohesive soils such as clay and silt are particularly likely to cause subsidence, since they shrink and swell depending on their moisture content. This means that the weather can have an enormous impact on their composition. Clay soil is found extensively across England and Wales, so this is a problem that will affect lots of people. - Non-cohesive soils being washed away.
Non-cohesive soils, like sand and gravel, are less susceptible to shrinkage and growth, but they are more susceptible to being washed away by water flow (such as when a water pipe is damaged).Our UK subsidence map to shows which areas of the country are most affected by subsidence. - Movement of varying soil structures. If there are different soil structures underneath a building’s foundations, then their movement can result in subsidence.
- Soil decomposition.
Some natural soils, such as peat, can decompose and cause ground movement. - Trees and other vegetation.
As much as that nearby tree or bush adds to the charm of where you live or work, there is the possibility that it could be causing subsidence to occur. Vegetation near the foundations can be a cause because roots suck moisture from the soil, causing it to shrink. This is more of a risk during long periods of dry weather as thirsty plants push their roots through building foundations in search of water. Oak, willow and poplar trees all absorb a lot of moisture from the soil.
Man-Made Causes of Subsidence
- Damaged drains.
Water escaping from damaged drains can sometimes soften, or even wash away the ground beneath the foundations, resulting in ground movement and, therefore, building movement. This issue usually affects sandy or gravelly soil. - Historic mine shafts.
Mines are another cause of subsidence. Areas where there was heavy coal mining will have several open areas underneath the ground, which can lead to subsidence. - Nearby traffic.
If a building is near to an area of heavy traffic, the resulting extended vibration can cause soil to move. - Improper ground preparation.
If a building or structure has been built on compressible clay soil and no ground preparation has been carried out, this will often lead to subsidence. - Construction work.
Vibrations & moving of soil at nearby excavations for can have negative effects. - Bad foundations.
Incomplete/poor quality foundation works can cause subsidence problems later down the line, especially if they have incurred water damage.
We Are Here To Help
If you are suffering from the effects of ground subsidence, or believe you are, then call in the Geobear team to sort the problem quickly and with no fuss. Call us on 0800 084 3503 or use our contact form to discuss your concerns. We are committed to providing a comprehensive solution for your problems.
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