Concurrent Delay in Construction

What genuine concurrency is

Concurrent delay, in the strict sense, is where an employer-risk event and a contractor-risk event each independently affect the completion date over the same period. The key word is independently: if either event alone would have delayed completion, and they overlap in time, you have genuine concurrency. Much of what is loosely called “concurrent” is not — it is simply two things happening at once, only one of which was actually driving the finish.

Why it matters

Concurrency is where entitlement to time and entitlement to money can diverge. A common outcome is that the contractor may be entitled to an extension of time (relief from liquidated damages) but not to prolongation cost for the concurrent period, because its own delay would have caused the overrun anyway. Getting this distinction right is central to a fair EOT assessment.

Assessing it

There is no single universally accepted approach, and contracts and jurisdictions differ. What consistently matters is:

• establishing the true critical path through each period;
• testing whether each event independently delayed completion;
• being honest about which delay was actually driving, rather than assuming concurrency to bridge a gap in the analysis.

This is where disciplined delay analysis and the SCL Protocol’s principles earn their place.

Records decide it

As with all delay questions, the answer is found in the contemporaneous record, not in argument. Whether concurrency genuinely existed — and what it did to the completion date — is a matter of evidence. A claim that leans on concurrency to explain away its own delay rarely survives scrutiny.

This is a general explanation of professional practice, not legal or contractual advice.