Extension of Time or Prolongation Cost? Two Claims That Arrive Together

A contractor asking for more time is asking for one thing. A contractor asking to be paid for that time is asking for another. Treat them separately.

An extension of time moves the completion date, which protects the contractor from late completion damages. Prolongation cost is money for the additional period they remain on site. They rest on different tests, and awarding one does not automatically mean awarding the other. Owners who treat them as a single request usually give away money they did not owe.

Extension of time at a glance

A change to the contractual completion date because an event for which the contractor is not responsible has delayed the works. The test is whether the event affected the critical path. Granting it removes your right to late completion damages for that period, but it does not by itself create any payment obligation.

Prolongation cost at a glance

Payment for the time related costs of remaining on site longer: site staff, accommodation, temporary facilities, plant standing, insurance and supervision. The test is what was actually incurred as a result of the delay, which means records rather than a rate multiplied by weeks.

The question being answered

Extension of time: Did the event move the completion date?

Prolongation cost: What did the extra period actually cost the contractor?

Evidence required

Extension of time: A programme analysis showing the event on the critical path.

Prolongation cost: Timesheets, invoices, hire records and site establishment costs for the period claimed.

Effect if you grant it

Extension of time: You lose the right to late completion damages for the extended period.

Prolongation cost: You pay real money now, and it is rarely recoverable later.

Common contractor tactic

Extension of time: Bundling several unrelated events into one large request so causes cannot be separated.

Prolongation cost: Claiming a daily rate for the site establishment rather than the cost genuinely incurred.

Common owner mistake

Extension of time: Refusing all extensions, which can undermine your own damages position later.

Prolongation cost: Paying a lump sum to close the file without seeing a single record.

When it should be decided

Extension of time: As close to the event as the contract allows, so the analysis is still possible.

Prolongation cost: After the time entitlement is settled, never before it.

When extension of time wins

• Events clearly outside the contractor control, such as a variation you instructed.
• Delay caused by late owner approvals, late free issue items or late access.
• Situations where you want the completion date to reflect reality so damages stay enforceable.
• Cases where the contractor is late but you also contributed, and the record needs to show it.

When prolongation cost wins

• Delay events where the contractor can evidence the resources genuinely retained.
• Long single delays, such as a suspension you instructed, where the cost is easy to trace.
• Cases where refusing a legitimate cost would push the contractor into cash trouble on your site.
• Negotiations where paying a fair time cost buys back goodwill and cooperation.

How to decide

Deal with time first and money second, in that order and in separate letters. If the event was not your responsibility, refuse the extension with reasons. If it was, grant the time that the programme supports and no more, then ask for the cost records that justify the prolongation claim and assess them line by line. Where the delay was partly yours and partly theirs, agree the apportionment in writing rather than leaving it to be argued at the end.

The single most useful document in either claim is the contemporaneous record: site diaries, the monthly programme updates, dated correspondence and photographs. A claim assembled a year later from memory tends to collapse under questions, and so does a defence assembled the same way. Because the consequences reach into contract rights, have your position on any substantial claim reviewed by a licensed adviser before you respond in writing.

Domira designs, builds and manages projects across Saudi Arabia for owners who are based abroad: land appraisal, feasibility, design, construction, handover and asset management under one accountable contract. Send us the plot or the brief and Domira will put the numbers in front of you before you commit.