When developing established properties, you may be required to underpin existing foundations to allow for improvement works to be carried out or to fix any problems such as subsidence. This is done by increasing the depth of the existing foundation in order to spread the load of the building.
Why underpin existing foundations?
A Structural Engineer should carry out an appraisal of the existing building and its foundations. If there is structural damage, the following should be included;
In the most cases where movement is the cause, it is important to investigate the depth of the existing foundations. This will involve testing the soil types below in order to establish an adequate stabilising depth of underpinning and should be carried out by an industry expert or engineer.
The operatives who complete the underpinning work should be competent; this will ensure that the workmanship is to the required level. The Association of Specialist Underpinning Contractors (ASUC) is a specialist contractor association who provide useful information on their website for underpinning works www.asuc.org.uk/.