Last edited 16 Mar 2018

Progress of construction works

Most construction contracts will include a date by which the works described in the contract must be completed. This is either by means of a defined completion date, or a commencement date and a specified period for the works. This date may be varied during the works, for example if an extension of time is granted, or if the works are accelerated.

If no date or period is defined, a term will be implied that the contractor must complete the works in a reasonable time, that is, the time it would ordinarily take, plus an allowance for any extraordinary circumstances.

Unless the contract includes express provisions requiring that the works are carried out in a particular way, the contractor can achieve the completion date in whatever manner they choose, for example, by starting slowly and then speeding up, or by working sporadically. There is no implied term requiring that the works are carried out to a specific timetable.

However, many contracts include express terms requiring that the contractor proceeds ‘regularly and diligently’ with the works, irrespective of whether they are likely to achieve the completion date. They cannot work sporadically, or slow down if it becomes apparent that they will beat the completion date. Sub-contracts may include similar obligations, requiring sub-contractor progress to be reasonably in accordance with the progress of the main contract.

The term ‘time at large’ refers to a situation in which there is no date for completion, or where the date for completion has become invalid. The contractor is then no longer bound by the obligation to complete the works by a certain date. They may however still be bound by an obligation to proceed regularly and diligently or to complete the works within a reasonable time.

Designing Buildings Wiki includes a number of articles providing more information about construction progress and its measurement: