Mr. Michael Horan:

The issue with subsidence, particularly in Cork city, where it has been a long-standing problem, is that it is due to the effect of naturally occurring water and leakage from the underground pipes on the limestone, which is characteristic of the area. The problem is exacerbated by the fact the underground pipes are made of clay and are susceptible to cracking when development takes place. This results in underground erosion, which causes downward movement of the ground supporting the existing properties. As I said, there is a particular problem in this regard in Cork.

In terms of remedial measures, with flooding, a flood defence can be put in that will protect a whole area, whereas with subsidence, the remedial measure is specific to the individual house. What needs to be done in general is to remove the cause of the damage, ideally, and then monitor for a period to make sure the movement of the property has stopped. Then, when one is sure the property has stabilised, underpinning work is carried out. Where subsidence has happened and underpinning work has been done, individual insurers would generally look favourably on this. As to whether the overall cause in Cork city can be removed, one of the issues there is the fact these clay pipes are cracking. In terms of removing the cause, I would have thought it would be a case of the local authority replacing the pipes, but I am not aware it has any plans to do that.