Concurrent delay means two or more delay events whose effects on the completion date overlap in time. Whether it exists, and what it means for time and money, depends on the schedule record, the analysis method and the contract. The calendar alone does not decide it.
What concurrent delay actually means
Concurrent delay is not established simply because two events occur in the same month. An analysis has to show that the events affected the same completion path during the same period. Industry guidance such as the SCL Delay and Disruption Protocol treats true concurrency as narrower than simple overlap, and analysts often disagree about where the line sits.
Questions that drive the analysis
- Which events occurred, and exactly when?
- Was each event on the critical path when it occurred, or did it only affect non-critical work?
- Was there more than one critical path at that time?
- What did the contemporaneous schedule update show, and who was responsible for each event under the contract?
- Do the contract terms define entitlement, float ownership or concurrency differently?
Why method selection matters
The same facts can produce different answers under different methods. A Time Impact Analysis measures the effect of each event on the schedule as it stood. A windows analysis divides the project into periods and identifies which path was driving in each one, which is the approach most often used to test for concurrency. As-built methods work back from what actually happened. The choice between them should follow the project record, not the result someone wants.
Whatever the method, it should be applied consistently. Switching methods midway because another one produces a better number is the quickest way to lose credibility with a reviewer.
Concurrency and pacing are different things
Pacing means deliberately slowing non-critical or non-driving work in response to a delay another party is responsible for. It can be a legitimate response, but it is generally only accepted when it is supported by contemporaneous evidence that the decision was made at the time. It cannot be credibly asserted after the fact.
A simplified illustration
Suppose an owner releases a work area 20 working days late in March, and in the same window the contractor's steel delivery slips 15 working days. If the steel activities were critical and the work-area release only affected work with 30 days of float, the owner's event used up float without delaying completion, and the steel delay alone drives the finish. If both chains were critical, the two delays overlap and the contract terms decide what follows. The dates are identical in both cases. Only the schedule shows which one applies. This example is hypothetical and simplified.
How the contract and law shape the outcome
How concurrent delay is treated varies. Some contracts and jurisdictions allow time but no money when both parties contributed. Others apportion, or treat the question differently. Notice requirements, float ownership clauses and limits on delay damages can all change the result. Those are legal questions for counsel. A schedule analyst's job is to establish, from the record, what happened and what it did to the critical path.
What to preserve during the project
- Every schedule update with its narrative, in native file format
- Daily reports, meeting minutes, RFIs and submittal logs
- Written notices of delay, with dates
- Photos and records that fix actual start and finish dates
A record that was kept as the project ran is what makes any of these methods possible. If you are already in a dispute, HADVEN's forensic delay analysis and extension of time claim support start with an inventory of what the record can and cannot support. For the schedule fundamentals behind all of this, read our guide to critical path analysis.