Have you experienced garden wall failure as a result of subsidence? Subsidence occurs in many soil types and can be attributed to many things like the weather for example. A wet winter followed by a hot summer followed by a wet winter on clay soil (As most of Greater London is built on) often wreaks havoc with the foundations of a property. Clay is a strange soil in that it is sticky when wet, can be rock hard when dry and when baked hard with sunlight can refuse to reform into its roiginal state. When this happens say under a foundation or a wall, we have subsidence.
Usually where garden wall failure subsidence is encountered, traditional underpinning is the best way to proceed. A section at a time, we will dig under the foundation after propping the house or garden wall first. This keeps the house in place whilst we start work on the structure. We then create a form into which concrete is poured – a form is literally the shape of a foundation usually built with a heavy duty plywood or steel sheeting. Once the concrete is cured, the form is removed and the support or propping is removed leaving your property well supported. The repair is virtually invisible once the removed subsoil is replaced.
As in the pictures below, where there is garden wall failure due to subsidence or ground movement, other areas will be affected too. A patio may manifest itself as uneven, cracks may even form across paving slabs as the support is simply not there – especially in areas where the footfall is high. Garden wall failure such as this, could also be caused by tree roots which often cause havoc in rigid structures such as houses or offices. Any good structural engineer should pick these issues up well before they happen, sadly in many cases a regular person will not recognise the signs, often until it is too late.