Construction Law/Idle Cost Claim


Dear Sir
Please comment, what type of method(s) shall be used for calculation of delay cost claim?
Is it logically not correct to use Day Work Schedule for Labour and Equipments rates, in respect of calculation of idle cost claim? Because these rates are given in the contract.
Is it necessary to use Construction Equipment Ownership and Operating Expense Schedule of U.S. Army Corps of Engineers for idle equipment cost claim?


Dear Jawaid,

Thank you for this question.

As is so often the case, the starting point is your contract. Some contracts define the term "cost"; for example, under a FIDIC Red Book contract "Cost" (capitalised C) is defined but "cost" (not capitalised) is not and, therefore, the two have different meanings.

As a general principle and subject to any contractual definition the measure of damages is the actual cost or loss incurred by the claiming. Daywork schedules or the US Army Corps. of Engineers' schedules are not costs; they are generalisations, intended for limited purposes.

Labour costs will be the actual basic cost incurred plus any allowance for necessary additional expenditure, such as but not limited to  insurances or taxes. The list of extra costs can be extensive.

Equipment costs will be different if hired than if owned; or if standing rather than working. The cost of hored equipment can be demonstrated easily from purchase invoices, but the cost of owned equipment can be very different depending upon the age of the equipment and its projected usage. For equipment the explanation for calculation is, unfortunately, too extensive for this forum.

The assessment of a cost addition (or reduction, depending upon the starting point) is easier as most manufacturers publish performance data and the  extra cost of running equipment can often be assessed from their statistics for fuel usages, and maintenance items.

I hope that this assists you.

Kind regards,
John Dowse

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John Dowse


Legal; contract interpretation; quantum; delay analysis. Practitioner in arbitration, adjudication and mediation.


Thirty-three (33) years experience in building and construction, at all levels both within contracting and consulting organisations. Practising arbitrator, adjudicator, and mediator. Faculty approved trainer for the Chartered Institute of Arbitrators. Lecturer on construction contract forms and dispute resolution practices.

Chartered Institution of Civil Engineering Surveyors Chartered Institute of Arbitrators Institute of Directors Society of Construction Arbitrators

Various UK and International construction and legal publications.

LLB (Hons), Pg Dip (Legal Practice), MCInstCES MCIArb MIOD Barrister

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