Essex is renowned for its rich clay base in its soils, the lowest layer which was transferred all over the county in heavy swaths by a subtropical sea roughly 50 million years back. This \’London Clay\’ (as it\’s better known as) has produced innumerable fossil finds through the years that demonstrate the diversity of creatures which lived on our soils prior to us. The excavations of the cement industry in Harwich, all through the 18th and 19th Centuries, found a number of notable fossils that chart the earliest incarnations of mammalian existence. To this day, Walton-on-the-Naze is known to be one of most internationally recommended locations for fossil hunting acclaimed locations for fossil excavations| internationally; where the London Clay deposits store some of the finest preserved bird fossils of the Tertiary age ever uncovered.
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 stop our houses from getting swallowed up by the Essex clay whilst we are living in them. One specific primary cause of subsidence is the removal of moisture content from soils and also because clay is far more susceptible to this than other soil types, people who live in Essex have to be especially wary. Warm dry periods could cause thirsty trees to travel further afield, dispersing root systems to withdraw more moisture than normal, resulting in the soil to shrink below the foundations of our properties. If you see cracks appearing on internal or external walls, or windows and doors starting to stick strangely, these could possibly be warning signs of subsidence. Subsidence cracks will typically be tapered in aspect, spreading diagonally, often coming from door or window frames and failing to seal up by themselves as time passes.
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.