Subsidence is defined as the gradual caving in or sinking of an area of land. Natural ground subsidence is unfortunately uncontrollable, there are ways to combat subsidence but essentially you are fighting against mother nature.
Depending on the ground that your property is built on you may be experiencing natural ground subsidence, the majority of properties that are built are either on rock, chalk or clay. As time passes the structure of the ground beneath your property changes, in some cases it compacts and sinks and in other cases it shifts in different directions.
There are multiple ways to combat against natural ground subsidence and choosing the correct method is essential to keep your property healthy.
In order to find out what the best method, a structural engineer has to carry out a structural survey, the surveyor looks at every aspect of the natural ground subsidence. This includes your properties surrounding area, drainage, trees, a geological map and much more. Once the surveyor has completed the survey they will have a good understanding of the issue.
If the surveyor has deemed the case of ground subsidence as minor, the movement has ceased and your property won’t suffer any further then a method called crack stitching is used. Crack stitching involves cutting into the walls of the affected area, adding in restraint bars and using epoxy resin to seal them in. In essence they stitch the wall back together, the cuts are then repointed and the wall is then painted so it looks as food as new.
If the surveyor believes that the subsidence is still active they will need to install a monitor to the affected area, the monitor will provide them with crucial information about which direction the ground is moving. Once the monitor has collected enough data to make the engineer aware of the grounds situation then they can put in place counter measures. The method most particularly used is called underpinning, this process involves extending your properties foundations to a further depth. With the extra depth your property structure should be able to withstand any extra movement. Crack stitching is also used to repair the visible damage.
If you believe that your property may be built in an area that’s experiencing natural ground subsidence, then feel free to give us a call and our engineers will do our best to provide adequate protections.