Essex is renowned for its rich clay base in its soils, the bottom layer of which was transferred throughout the UK in heavy swaths by a subtropical sea approximately 50 million years back. This ‘London Clay’ (as it’s better known as) has yielded innumerable fossil finds throughout the years which illustrate the diversity of animals which inhabited our soils prior to us. The excavations from the cement industry in Harwich, throughout the 18th and 19th Centuries, discovered several remarkable fossils that document some of the earliest incarnations of mammalian life. Even now, Walton-on-the-Naze is known to be one of most worldwide acclaimed sites for fossil excavations well known locations for fossil hunting| internationally; while the London Clay deposits have some of the finest preserved bird fossils from the Tertiary age ever found.
But it does not stop there. On top of the London Clay sits an additional (more sandy) clay known as the Claygate Beds. The plateau of Boulder Clay that currently covers a substantial proportion of northern Essex had been dispersed here far later. Some 450,000 years back, a severe cold period triggered a giant ice sheet to disperse south across the valley of the early Thames. At first, the Thames took a more northerly course (passing through Chelmsford, Colchester, Harlow) ending at the sea at Clacton, where it had been intersected by the River Medway. When the Anglian glacial ice sheet moved across the county, it redirected the path of the Thames in to its present location (pretty much, although at Southend it still flowed north to Clacton) which left the significant layer of surface till (Boulder Clay) daubed across Essex in its aftermath.
In conclusion – Essex consists of layer after layer (upon layer) of clay based soils. This can explain precisely why Essex is more susceptible to subsidence compared to most locations in the UK. But it is more complicated than this, to talk about the full geological history of the soil spanning the Essex area would take much longer. Subsidence problems were never a problem for the original human occupants of Essex, of which we understand to have lived here approximately 400,000 years back (due to the worked flints found in Clacton-on-Sea, currently termed as Clactonian tools as a result), but modern houses are certainly at risk. Just how can we stop our mighty houses from turning into the subject of archaeological study in yet another half a million years? The simple response is: we won’t.
What we are capable of doing, is attempt to prevent our houses from being swallowed up by the Essex clay whilst we continue to be residing in them. One of the main causes of subsidence is the extraction of moisture from soils along with the fact that clay is far more susceptible to this than other soil types, people in Essex have to be especially wary. Warm dry periods can lead to thirsty trees to travel further afield, spreading out root systems to take in more moisture than usual and causing the soil to reduce in size beneath the foundations of our homes. When you notice cracks appearing on interior or exterior walls, or doors and windows beginning to stick strangely, these could possibly be signs of subsidence. Subsidence cracks will typically be tapered in appearance, spreading diagonally, usually emanating from door or window support frames and failing to close up by themselves over time.
Investigations to look for the cause of a subsidence issue are generally carried out by chartered surveyors.
Clacton property owners must seek the help of a surveyor as soon as they notice any of the tell tale warning signs of subsidence. Surveyors within Clacton are able to manage inspections into the reason behind your subsidence, seeking specialist advice where needed from arboroculturists and / or soil technicians. When the root cause has been diagnosed, your surveyor will be capable of recommending a strategy to eliminate the cause and/or perform restorative works to set right any deterioration already done.
For anyone who’s unlucky enough to discover a subsidence issue, you are normally permitted to employ your own personal surveyor (for example, Clacton surveyors) to help you with your insurance claim and recover the expenses from your insurers.