Building Insurance & Neighbour Property Damage

We plan to redevelop an investment property. The location of this property is waterfront so ground/foundations largely made up of sand. The neighbours request that we pay for a structural engineer to inspect their property before + after the build as well as pay for any damage found arising from these reports. The neighbours houses are very old + already have foundation sinking issues. Would we the owners be liable or would such damage be covered by the builders insurance???