Subsidence is the gradual sinking of a section of land or property. Terrain moves naturally in very small increments and has very minimal or no impact on properties on the surface of that terrain. However, this downwards movement is quicker and has the potential to damage properties.
Subsidence does not happen overnight and is a slow process just like the natural movement of terrain. However, it has more severe consequences on the structural integrity of foundations. Any movement of terrain under and around a foundation causes negative effects on properties leading to small issues such as cracking of wall plaster to more severe concerns such as loss of structural integrity.
There are many causes for downwards movement of terrain as well as many ways to spot signs of it. The most common time is during the summer, these long periods of dry weather can drastically change the terrain around a property. This dry ground heats up quicker than normal wet and healthy terrain causing an inwards shift of terrain.
Other causes include the type of soil combined with the quantity of clay, clay is sensitive to changes in weather and temperature causing issues such as subsidence as well as upwards movement of terrain named heave.
Damaged drains near the foundation of your property also have an impact on the rate and severity of subsidence. Damaged drains can create continuous water pressure on your foundation, this may cause damage such as erosion of foundations. These drains can also work to soften the terrain around your foundation due to the increased flow of water.
Signs of Subsidence
Signs of subsidence range from obvious to obscure so it can be hard to spot damage in a property and know if you have subsidence.
An obvious sign of subsidence is the drop of flooring in a property. Flooring will appear to sink downwards into the foundation. Both skirting boards and uneven surfaces around a property will also crack and create gaps. These cracks can be caused by other environmental factors so do not assume every crack is subsidence. You should only contact an expert surveyor to check your property if your property contains many of the issues listed here.
Largely sized cracks can appear around your property, these cracks can appear near extensions to your properties. These cracks, as well as warping, should start the show around window and door frames. These warps are another telltale sign of subsidence and should be visible from the interior and exterior of a property.