Concurrent delay claims arise when two independent events, one the owner’s fault and one the contractor’s, both push the project’s completion date later during the same stretch of time. The usual outcome is that the contractor receives an extension of time but no money for delay costs, and the owner loses the right to collect liquidated damages for the overlapping period. Whether that default holds in your dispute depends almost entirely on whether a forensic schedule analysis can separate each party’s delays, and on what your contract says about delay damages.
What Counts as a Concurrent Delay
The word “concurrent” has a specific meaning in construction disputes. Two or more delays caused by different parties must both affect the project’s completion date during the same period, and each must independently be capable of pushing the finish date later. One is typically an owner-risk event like failing to deliver approved drawings or denying site access. The other is a contractor-risk event like insufficient workforce or poor subcontractor coordination.
The delays do not have to start and stop on the same calendar dates. True calendar-day alignment is rare. What matters is overlap in effect on the critical path, the longest chain of dependent tasks that determines the earliest possible completion date. A delay that hits only a non-critical activity with enough float to absorb the impact doesn’t move the finish date, so it doesn’t count toward concurrency no matter when it happens.
This is where many claims collapse. A party will point to an event that happened during the same week as the other side’s delay, but if the event affected a task with three weeks of float, it was never driving completion. The overlap has to be real and path-critical, not just a chronological coincidence.
The Default Outcome: Time for the Contractor, No Money Either Way
The most widely applied rule for true concurrent delay is that the contractor gets an extension of time but no financial compensation for delay-related overhead. The logic is straightforward. Since the contractor would have been delayed anyway by its own fault, it cannot prove that the owner’s delay caused the additional costs it incurred for site trailers, equipment rental, and supervision staff. Those costs would have accrued regardless.
The flip side protects the contractor. The owner cannot enforce liquidated damages for a period when its own actions also drove the delay. Courts call this the prevention principle: a party cannot penalize the other side for late completion when it contributed to that lateness. The practical effect is a standoff. Neither side recovers for the overlap. The contractor avoids liquidated damages, and the owner absorbs its own losses from delayed revenue or occupancy.
The money at stake is often substantial. Liquidated damages clauses set a predetermined daily rate the contractor owes for each day of late completion. On large commercial projects, those rates can run from several hundred dollars to tens of thousands of dollars per day, so even a few weeks of concurrent delay can represent significant financial exposure for either party.
This default sits at the intersection of the three basic delay categories. Owner-caused delays are normally excusable and compensable, giving the contractor both time and money. Weather, epidemics, and strikes are excusable but non-compensable, giving time but not money. Contractor-caused delays are non-excusable, giving neither. Concurrent delay is what happens when an excusable delay and a non-excusable delay land on the critical path at the same time, and the dominant answer in both U.S. and English law is that the contractor still gets the time extension but typically cannot recover delay costs.
How U.S. Courts Split the Delay When They Can
U.S. courts have moved through two approaches, and the difference drives how you build your case.
The older, traditional rule holds that when both parties contribute to the overall delay and the effects cannot be separated, neither side recovers. Courts reasoned that they should not take on the impossible job of dividing an intertwined delay. Under this approach, the owner cannot collect liquidated damages and the contractor cannot collect delay costs.
The modern rule, now followed by most federal courts and the U.S. Court of Federal Claims, allows recovery when the delays can be segregated. A party may recover damages, but only when clear apportionment of the delay attributable to each party has been established. The party seeking recovery carries the burden of separating its delays from delays chargeable to the other side. If that separation cannot be made, the delays are treated as concurrent and neither party recovers.
This is not a comparative-fault percentage split. Courts apportion days, determining how many days of delay each party caused, rather than assigning a percentage of blame for a single event. The practical consequence is that the quality of your schedule analysis often determines the outcome. If your forensic expert can isolate specific windows where only the owner’s actions drove the critical path, those days become recoverable even if other periods were truly concurrent. The inability to separate delays is what triggers the no-recovery default, so the investment in rigorous schedule analysis pays for itself.
The Malmaison Approach in English and International Disputes
If your contract is governed by English law, or if your dispute goes to international arbitration, a different framework may apply. English courts developed the Malmaison approach in Henry Boot Construction (UK) Ltd v. Malmaison Hotel (Manchester) Ltd. It holds that when two concurrent causes of delay exist and one is an employer-risk event under the contract, the contractor is entitled to an extension of time for the employer delay regardless of the concurrent effect of its own delay. The contractor-caused delay does not cancel out the owner’s responsibility for its portion of the problem.
Later decisions reinforced the point. In De Beers UK Ltd v. Atos Origin IT Services UK Ltd, the court confirmed that the contractor gets the time extension but cannot recover costs for delay where it would have suffered the same loss due to causes within its own control. The same logic appeared again in Thomas Barnes & Sons plc v. Blackburn with Darwen Borough Council in 2022.
The Society of Construction Law’s Delay and Disruption Protocol, widely referenced in international construction disputes, endorses a similar position. It states that where contractor delay occurs concurrently with employer delay, the contractor’s concurrent delay should not reduce any extension of time due. The Protocol deliberately takes no position on whether the contractor can recover prolongation costs during concurrent delay, noting that this depends on the contract terms and governing law.
U.S. practitioners should know Malmaison because many cross-border construction contracts are governed by English law, and arbitrators familiar with the approach may apply similar reasoning even under U.S.-governed contracts.
When a “No Damages for Delay” Clause Changes the Answer
Many construction contracts include a “no damages for delay” clause that limits the contractor’s sole remedy for any delay to a time extension, regardless of cause. Under the standard AIA A201-2017 general conditions, the contractor receives no financial compensation for delay or hindrance of the work, and the owner is not liable for any damages arising from delay regardless of its source. The contractor’s only remedy is more time.
Courts generally enforce these clauses, but they are not bulletproof. Four judicially created exceptions can override them:
- Active interference or bad faith, where the owner deliberately hindered the work through willful misconduct rather than ordinary negligence or passive failure.
- Unreasonable duration, meaning a delay so extreme it essentially destroys the purpose of the contract. There is no bright line, but courts have found that a 90-day delay was not unreasonable while a two-and-a-half-year delay was.
- Delay not contemplated by the parties, meaning the type of delay was not reasonably foreseeable when the contract was signed. Some courts reject this exception entirely, reasoning that the clause itself contemplates all delays.
- Breach of a fundamental obligation, rarely invoked but available when the owner violates a core contractual duty.
In a concurrent delay scenario, these clauses add another layer. Even where the contractor could otherwise argue for compensable delay damages, a no-damages-for-delay provision may shut the door completely. Roughly a dozen states have statutes voiding these clauses in public construction contracts, and a handful extend the prohibition to private contracts as well. Whether your contract is governed by one of those states can dramatically change the financial calculus.
The AIA A201-2017 suspension clause adds its own wrinkle. If the owner suspends work for convenience, the contractor gets both time and cost adjustments, but not to the extent the delay would have occurred anyway from a cause the contractor is responsible for. That carve-out is essentially a concurrent delay provision built into the standard form.
Pacing Is Not Concurrent Delay
One of the most common misidentifications in delay disputes is confusing a pacing delay with a concurrent delay. A pacing delay happens when one party deliberately slows its work to match the pace of a delay caused by the other side. If the owner’s late design approval pushes the critical path by six weeks, and the contractor consciously scales back its crew to align with the new timeline rather than sitting idle at full staffing levels, the contractor’s reduced output is a pacing delay, not independent concurrent delay.
The distinction matters because pacing is a voluntary, rational response to someone else’s delay, while concurrent delay involves two genuinely independent causes. A contractor who paces should not lose its right to claim the full period of owner-caused delay. But if the owner can recharacterize the contractor’s reduced output as an independent delay, the contractor’s claim shrinks. Proving that a slowdown was deliberate pacing rather than independent poor performance requires contemporaneous documentation showing the contractor’s decision and its link to the owner’s delay.
Proving the Claim: Forensic Schedule Analysis
Proving or defeating a concurrent delay claim depends almost entirely on technical schedule analysis. Several recognized methods exist, each with different strengths depending on the quality of available project records.
Critical path analysis is the foundation. The critical path is the longest continuous chain of dependent activities from project start to finish. Any delay to a critical activity delays the entire project by the same amount, while delays to non-critical activities can be absorbed by float, the slack time available before that activity becomes critical. Identifying which path was critical at the time the delay occurred is the first step in any forensic analysis.
The “but-for” test asks a simple counterfactual: would the project have finished on time but for this party’s actions? It works well when delays are sequential, but it breaks down when two independently sufficient causes overlap, which is exactly the situation in concurrent delay. When the but-for test fails, analysts turn to more sophisticated methods.
The collapsed as-built method starts with the actual project timeline as it was built and removes specific delay events to see how the schedule would have looked without them. By selectively removing owner events, then contractor events, the analyst can measure how many days each party’s delays contributed to the overrun. AACE International’s Recommended Practice 29R-03 classifies this as a “modeled subtractive” method and recognizes it as one of several legitimate analytical approaches.
Time impact analysis works in the opposite direction. It starts from the baseline schedule and inserts delay events one at a time in chronological order, measuring the effect of each event on the critical path as it existed at that moment. This method is generally considered the most rigorous because it captures the dynamic nature of the schedule as delays shift the critical path over the life of the project.
Window analysis divides the project into discrete time periods and analyzes critical path delays within each window separately. This approach is particularly useful for concurrent delay because it can reveal that delays were concurrent in one window but sequential in another, allowing for partial apportionment.
No schedule analysis can overcome bad records. The baseline schedule is the starting reference point, capturing the original planned sequence of work, activity durations, logic ties, and the critical path as it existed before any changes. Updated schedules submitted during the project document how the plan changed over time, capturing new critical paths as delays accumulated. Daily logs should record weather conditions, crew sizes, equipment on site, work performed, and any disruptions encountered. Correspondence between the parties fills the gaps, creating a timeline of who knew what and when.
Notice Deadlines That Can Kill the Claim
Most construction contracts require written notice of delay events within a specific number of days, often ranging from 7 to 21 days depending on the contract form. Under AIA A201-2017, a contractor must provide notice of a claim for additional time in accordance with the contract’s claims procedures, and the claim must include an estimate of cost and probable effect on the progress of the work. ConsensusDocs agreements require “prompt written notice,” which is generally interpreted as faster than the notice periods for regular change orders and means notifying the owner as soon as a potential delay event is identified rather than waiting to quantify the impact.
Missing these deadlines can bar the claim entirely, even if the delay was real and well-documented. Sending a generic notice preserves your rights. Waiting until you have perfect information risks losing them.
Whichever contract form governs, the concurrent delay question ultimately comes back to the same two inquiries: can the delays be separated, and if so, how many days belong to each side? The contract form determines what categories of delay entitle the contractor to relief. The schedule analysis determines whether the specific facts meet those categories. Getting both right is what separates a successful claim from an expensive lesson.