Concurrent Delay on Ontario Projects: Time, Money and the Gap Between Them

Concurrency is often asserted loosely to mean that the other party also had problems. Analytically it means something narrower: two or more delay events, the responsibility for which lies with different parties, each independently causing critical delay to completion, with effect in the same period.

Two events in the same month, one of which is on the critical path and one of which is consuming float, are not concurrent. Neither are events where one is simply the consequence of the other. Distinguishing genuine concurrency from sequential or derivative delay is most of the analytical work.

The practical consequence of concurrency is asymmetric. Where an employer-risk event and a contractor-risk event concurrently delay completion, the contractor will commonly obtain relief from liquidated damages for that period, while recovery of prolongation cost for the same period fails: the contractor would have incurred that time-related cost in any event because of its own delay.

That asymmetry is why a claim built solely around cost recovery can collapse while the same facts would have supported a sound extension of time application. Deciding which relief actually matters to the project, before drafting, avoids that outcome.

Contract wording changes the answer. Some agreements are silent, leaving the position to be argued on general principles. Others contain express concurrency provisions that allocate time and cost explicitly, and some standard-form amendments used on Ontario infrastructure work reduce or remove relief where contractor delay is concurrent.

Where the contract addresses concurrency directly, the analysis method should be chosen to answer the question the contract poses — typically a windows or time-impact approach applied period by period, rather than a single global comparison of planned and actual completion.

We set out, for each window, what was critical, which events affected the critical path, whose risk each event was, and what relief follows for time and for cost separately. A reviewer should be able to disagree with one window without discarding the whole analysis.

Overstating concurrency as a defence is as damaging as ignoring it as a claimant. Both invite a tribunal to treat the analysis as advocacy rather than evidence.