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Concurrent delay

When owner and contractor delays overlap — the most contested question in delay analysis.

Working definition

Concurrent delay generally concerns two or more independent delay events—often allocated to different parties—whose effects on completion occur in the same period. The definition and remedy vary by contract and governing law. The SCL Protocol’s English-law-oriented guidance treats true concurrency narrowly, allows an employer-risk event to support time relief despite concurrent contractor delay, and does not make compensation automatic.

Key takeaways

  • Under the SCL Protocol formulation, each event must be an effective cause of delay to completion, with the effects felt at the same time.
  • Pacing is when one party deliberately slows its own work because the other party’s delay has made haste pointless — the classic example is a contractor decelerating trailing trades while awaiting an owner-caused redesign.
  • A period-by-period analysis can establish where the controlling path ran, place each event against that path, and test whether each event was an effective cause of completion delay.
01

True concurrency is narrower than it sounds

Under the SCL Protocol formulation, each event must be an effective cause of delay to completion, with the effects felt at the same time. Calendar overlap alone is therefore insufficient. Other contracts and jurisdictions may frame concurrency differently, so the analyst should state the adopted definition, trace each event to the relevant path and milestone, and reserve the legal consequence for the authorized decision-maker.

02

Pacing: the deliberate look-alike

Pacing is when one party deliberately slows its own work because the other party’s delay has made haste pointless — the classic example is a contractor decelerating trailing trades while awaiting an owner-caused redesign. Pacing is a defense against a concurrency finding: the slowdown was a response to the delay, not an independent cause of it. Distinguishing pacing from genuine contractor delay turns on evidence of intent and timing — which, again, means the contemporaneous record.

03

How analysts untangle it

A period-by-period analysis can establish where the controlling path ran, place each event against that path, and test whether each event was an effective cause of completion delay. The selected method must fit the available records, information date, contract, and purpose; reliable status updates make that analysis more transparent, but the analyst should disclose gaps rather than manufacture precision.

Sources and scope

Follow the reference trail.

This guide is original educational commentary. Kairos reference records identify the source organizations, editions and scope behind this guidance. The original publishers retain their publications and rights.

10S-90: Cost Engineering TerminologyAACE International · checked 2026-08-01Recommended Practice 29R-03: Forensic Schedule AnalysisAACE International · checked 2026-08-01Delay and Disruption Protocol, second editionSociety of Construction Law · checked 2026-08-01