Last edited 04 Sep 2020

Prolongation in construction contracts

As per the definition contained in the Society of Construction Law Delay and Disruption Protocol the term ‘prolongation’ refers to 'the extended duration of the works during which time-related costs are incurred as a result of a delay' - usually recognised as the additional projected time required to complete a contract extending beyond the contractual completion date.

Prolongation costs are the additional costs that a contractor has incurred as a result of the completion of the works being delayed by an event that is the responsibility of the other party (usually the Employer). Such events might include; failing to give the contractor possession of the site on the date specified in the contract; delays in giving instructions, and so on.

The contractor may incur additional costs as a result of having to remain on site for longer than anticipated, for example, additional labour costs, plant costs, off-site overheads, fluctuations, and so on.

Prolongation is sometimes described as being synonymous with ‘loss and expense’, however, this is incorrect. Loss and expense is a wider term that refers to matters which are the responsibility of the client that materially affect the progress of the works. This includes matters that disrupt, rather than delay the progress of the works, but still entitle the contractor to make a claim for additional costs incurred. Claims for disruption result from the additional cost of adopting inefficient working methods as a result of the disruption.

For more information, see Disruption claims in construction.

Prolongation and disruption therefore are two separate elements that might result in a claim for loss and expense. The prolongation element is dependent on the completion date being delayed.

Depending on the terms of the construction contract, prolongation might relate to the project as a whole, or to a specific aspect of it.

Generally a disruption event is easier to prove than a critical delay prolongation event i.e. a failed critical delay prolongation claim will often be used as proof of disruption. However, prolongation costs are often considered easier to demonstrate than disruption costs.

For more information see: Loss and expense.

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