One of the duties of the engineer is to decide when the works can be considered complete. Most contracts require that the works are substantially complete before the engineer can issue his certificate of substantial completion. Unless the contract has specific requirements to be met, substantial completion does not require that every last item is finished, but it is generally taken to mean that most of the works are done and the project can be put to safe and effective use by the employer. There will no doubt be some items outstanding and conditions, such as ICE (7th edition), allow for this while requiring that any outstanding work is completed as soon as practicable during the defects period or to an agreed timetable. Items left to be finished later would be those which do not affect operation, such as painting; or may even include minor structures, such as a gatehouse not essential to use of the works.
A shrewd contractor will be looking to get his certificate of completion as early as possible and may apply to the engineer as soon as he thinks he has any chance of it being allowed. Clause 48 of the ICE conditions (7th edition) allows for such an application which must, however, be accompanied by an undertaking to finish outstanding work. The engineer must then either issue a certificate, or state what needs to be done to complete. The resident engineer must advise the engineer of matters still to be completed and say if he considers the contractors application for completion is too early. Before the engineer issues his certificate of completion he will need to check with the employer to ensure that he has staff available to take over completed works.