A. If you have noticed cracks either within the interior or on the exterior of the property you may have subsidence. The cause for this occurrence is often poor soil conditions or where further weight has been added to the building such as added story’s or heavier roof coverings etc, leaving the foundations unable to hold the extra weight. As suggested you should in the first instance employ the services of a structural engineer who will survey the property and maybe put a monitoring program in place. He may advise though that the problem is shrinkage cracks or fractures due to roof spread etc.
If the property is deemed to have subsidence then it will need to be underpinned. Again the structural engineer would normally oversee this work in conjunction with a building control officer from the local authority with a reputable contractor actually carrying out the underpinning process.
Most building insurance policies will cover subsidence and underpinning work although the excess may be quite high. Check your policy before you commence any works.
When the work has been successfully completed you will receive a report from the structural engineer and a sign off certificate from your local authority. These are important documents and should be safely kept as these will be required if and when you sell the property. They will also be required by your insurer.