Concurrent Delay

Concurrent delay occurs when an Employer-risk event and a Contractor-risk event both delay the same period of project time. Under English law, the treatment of concurrent delay is one of the most contested areas of construction contract practice. The conventional position — known as the Malmaison approach — is that the Contractor is entitled to an extension of time for the Employer-caused delay even if a Contractor-caused delay would have produced the same effect. But this is not universally applied, and contracts can (and increasingly do) include specific clauses that allocate concurrent delay risk differently.

The distinction between concurrent delay (where both events are on the critical path simultaneously) and pacing delay (where the Contractor deliberately slows work to match an Employer-caused delay) is important in dispute. Pacing is generally not concurrent delay — the Contractor was not being delayed; they chose to match the pace. Getting this classification right typically requires detailed contemporaneous schedule evidence and is often where delay expert reports disagree.

The SCL Delay and Disruption Protocol discusses concurrent delay at length and recommends express contract drafting on how it should be handled, because implicit treatment through default law produces disputes. For project controls, the practical implication is that delay records and schedule updates need to capture not just what happened but when each event became critical, so the analyst can determine whether the events were truly concurrent or sequential. Weak contemporaneous records make concurrent delay determination impossible to defend.