Concurrent delay in construction happens when the owner and the contractor each cause a schedule slip during the same window on the project’s critical path, and the usual result under the most widely applied rules is that the contractor receives a time extension but no delay damages, while the owner loses its liquidated damages for that overlapping period. That outcome is not universal. The jurisdiction, the exact contract wording, and the quality of the schedule evidence each side produces can shift the result from a clean split to a total loss for whichever party carries the burden of proof.
What Actually Counts as Concurrent
Two problems happening at the same time are not automatically concurrent in the legal sense. For concurrency to exist, both events must independently affect the project’s critical path during the same period. If a supply shortage holds up framing while a design error stalls electrical rough-in, they are concurrent only if both of those activities sit on the longest chain of dependent tasks controlling the completion date. A delay to a non-critical activity with available float is just a delay. It does not create concurrency, and it does not entitle the contractor to anything.
Decision-makers use two tests to sort causation. The But-For test asks whether the project would have finished late even if one of the competing events had never happened; if removing either event still leaves the project behind because of the other, the delays are concurrent. The Dominant Cause test asks which event had the greatest practical impact and lets that answer drive the outcome, setting lesser factors aside.1ASCE Library. Concurrent Delays in Construction: International Legal Perspective The choice matters. But-For tends to produce shared outcomes. Dominant Cause can pin the whole result on one party.
The Delay Categories That Collide
Concurrency only becomes a fight because the individual events fall into categories with different financial consequences. Construction contracts recognize four:
- Excusable delays: events beyond the contractor’s control such as severe weather, strikes, government actions, and epidemics, which entitle the contractor to more time without financial penalty. Federal construction contracts under FAR 52.249-10 list qualifying causes including natural disasters, government acts, quarantine restrictions, and unusually severe weather.2eCFR. 48 CFR 52.249-10 – Default (Fixed-Price Construction)
- Inexcusable delays: contractor-caused problems like poor workforce planning, equipment breakdowns, or subcontractor mismanagement, which expose the contractor to liquidated damages or termination for default.
- Compensable delays: owner-caused problems such as late site access, slow permit approvals, or mid-project design changes, which entitle the contractor to both time and money for extended overhead and disruption costs.
- Non-compensable delays: events that earn the contractor more time but no money. Force majeure typically lands here.
The concurrent delay question sharpens when events from different categories overlap. An excusable delay running alongside an inexcusable one, or an owner-caused delay overlapping with a contractor-caused one, forces someone to decide which category controls. The contract’s changes clause, force majeure provision, and any concurrent delay language usually dictate that priority.
How Courts and Tribunals Split the Fault
Three frameworks dominate the allocation question, and each produces meaningfully different financial results.
The Malmaison Approach
The 1999 English case of Henry Boot Construction (UK) Ltd v Malmaison Hotel (Manchester) Ltd set the most widely applied rule in common-law construction disputes. Where true concurrent delay exists, the contractor receives a full extension of time but no delay costs.3CICES. Concurrency and the Prevention Principle The result is a stalemate. The owner cannot collect liquidated damages for the concurrent period. The contractor cannot recover extended overhead or lost productivity. Neither side profits from a delay both helped create.
This approach appeals because it is simple. It draws a clean line: time yes, money no, no need for a granular assessment of degree of fault. Its weakness is that it treats a 90/10 owner-heavy delay the same as a 10/90 one.
The City Inn Apportionment Approach
The Scottish case of City Inn Ltd v Shepherd Construction took the opposite path. Where no single dominant cause can be identified, the tribunal apportions the delay between the parties based on how significant each event was and the degree of culpability each party bears.4IRBnet. Apportionment and City Inn: Save it for the Scots A judge might find the owner 70% responsible and the contractor 30% responsible, then adjust liquidated damages and delay costs by that ratio.
Apportionment produces outcomes that feel fairer where fault is lopsided, but it is expensive. Both sides need detailed forensic schedule analysis and expert testimony to support their proposed split, and reasonable experts routinely disagree.
The Traditional U.S. Rule
American courts have historically taken a harder line. Under cases such as Blinderman Construction Co. v. United States and Essex Electro Engineers, Inc. v. Danzig, when concurrent delays are so intertwined that the parties cannot separate their respective contributions, neither side recovers delay damages. The party seeking recovery bears the burden of proving which delays belong to the other side. If that separation is impossible, the claim fails entirely. Depending on the contract and the facts, the contractor may lose not just delay costs but the time extension too. Modern CPM tools have softened this in practice, because it is now often possible to isolate the effects of individual events in ways older courts considered impossible.
The Prevention Principle
Sitting underneath all of this is the prevention principle: an owner cannot enforce a deadline, or collect liquidated damages for missing it, if the owner’s own actions prevented the contractor from finishing on time. When owner-caused delay runs concurrently with contractor-caused delay, the principle sets a floor. Even if the contractor contributed, the owner’s contribution can block the owner from collecting delay penalties unless the contract provides a mechanism for extending time.3CICES. Concurrency and the Prevention Principle This is why well-drafted contracts always include an extension-of-time clause. Without one, the owner risks losing its liquidated damages remedy entirely the moment any portion of the delay traces back to its own actions.
Pacing vs. True Concurrency
One of the most contested issues in delay analysis is separating a pacing delay from a genuinely concurrent one. Pacing happens when the contractor deliberately slows work on one activity because an owner-caused delay has already pushed the completion date beyond reach. The logic is straightforward. If the owner’s late design revision has already delayed the project by two months, there is little reason to rush an independent activity that now has slack.
Courts and boards have recognized that contractors are not required to race toward a completion date the owner has already made impossible. A contractor who paces work in response to an owner delay is not creating a new concurrent delay. The contractor is adjusting to reality.
The danger is in the proof. If the contractor cannot show that the slowdown was a deliberate response to an identified owner delay, the owner’s schedule analyst will recharacterize the pacing as contractor-caused concurrent delay, which typically kills the delay damages claim. The difference between “we slowed down because acceleration was pointless” and “we fell behind on our own” comes down to contemporaneous documentation: meeting minutes, letters to the owner, and updated schedules showing the reasoning.
What a No-Damage-for-Delay Clause Does to All of This
Many construction contracts include a “no damage for delay” clause, which bars the contractor from recovering financial compensation for owner-caused delays. The contractor still gets time extensions but cannot claim extended overhead, lost productivity, or escalation costs. In a concurrent delay dispute, the clause eliminates the contractor’s primary financial remedy before the fault analysis even begins.
Courts have carved out several exceptions where the clause will not be enforced even when the language is unambiguous:
- Bad faith or active interference by the owner. This is the most widely recognized exception.
- Unforeseeable delays, in some jurisdictions, where the delay was not reasonably foreseeable when the contract was signed.
- Abandonment, where delays are so extreme in duration that the owner has effectively walked away from the project.
- Fundamental breach, where the owner’s actions did not just slow the project but made performance impossible.
Several states have gone further and enacted statutes that void no-damage-for-delay clauses on public construction contracts, and some extend the prohibition to private contracts. Enforceability varies enough that a clause valid in one state may be void next door. Read the clause and the governing law together before assuming it controls.
What the Fault Finding Actually Costs
The practical result of a concurrent delay determination comes down to three financial levers: the time extension, liquidated damages, and delay cost recovery.
Time Extension, No Delay Costs
Under Malmaison and the Society of Construction Law’s Delay and Disruption Protocol, the most common outcome is more time and no money. The Protocol defines true concurrent delay as requiring both events to affect the critical path during the same period, and takes the position that contractor concurrent delay should not reduce any extension of time the contractor would otherwise receive. The extension moves the contractual completion date, which protects the contractor from default termination and shields against liquidated damages during the concurrent period. But the contractor absorbs its own extended overhead: field office costs, supervision, insurance, equipment rental. For the owner, the liquidated damages clock stops for that period. On a project running daily LDs in the thousands, that is a real financial hit.
Liquidated Damages Under Apportionment
Where an apportionment framework applies instead of Malmaison, liquidated damages may be reduced proportionally rather than waived. If a tribunal finds the owner 60% responsible for a 100-day delay, the contractor might face LDs for only 40 of those days.
Home Office Overhead and the Eichleay Formula
Contractors on delayed projects often seek unabsorbed home office overhead, which is the ongoing cost of running the main office that the delayed project was supposed to help cover. The Eichleay formula is the standard method for calculating this recovery on federal contracts. It requires the contractor to show that the delay was caused by the owner and that the contractor was on standby, unable to take on replacement work. Concurrent delay usually breaks that chain. The contractor’s own contribution to the delay defeats the causation showing Eichleay demands.
The Duty to Mitigate
Whoever caused the delay, both parties have to take reasonable steps to reduce the financial damage. Owners often argue that the contractor should have reassigned idle workers and equipment to other projects during the delay. In practice, that is rarely simple: workers may not be interchangeable, mobilization costs money, and commitments to other owners limit flexibility. A contractor who made no effort at all will still see any damages award reduced. The duty runs the other way too. An owner that caused a delay and then refused to approve a reasonable acceleration plan or a resequencing of work may find its own failure to mitigate reduces or eliminates its liquidated damages claim.
Evidence That Decides the Case
Concurrent delay disputes are won on documentation. The party with better records controls the narrative. The party without contemporaneous evidence usually cannot meet its burden.
Critical Path Method Analysis
The single most important piece of evidence is a forensic analysis of the project schedule using the Critical Path Method. CPM identifies the longest chain of dependent activities that controls the completion date. If any activity on that chain slips, the whole project slips.5Federal Highway Administration. CFL Guidelines for Developing Critical Path Method Schedules A delay to an activity off the critical path, however painful it felt in the field, does not delay the project as a whole. Forensic analysts compare the original baseline schedule against periodic updates and the as-built record to trace exactly when and why the critical path shifted, showing which events pushed the completion date and by how much. Without that specificity, the claim collapses into a general assertion that things went wrong, which decision-makers consistently reject.
Contemporaneous Project Records
Beyond the schedule, parties need daily field logs recording weather, labor counts, equipment on site, and tasks completed. Inspection reports, RFI logs, and submittal tracking fill in the gaps between schedule updates. Meeting minutes are especially valuable because they create a real-time record of when problems were first raised and what each party committed to do. Timestamped photographs corroborate the written record. The absence of these records does more than weaken a claim. It can make the parties’ respective delays impossible to separate, which under the traditional U.S. rule means neither side recovers.
Notice Deadlines
Nearly every construction contract requires the contractor to give written notice of a delay within a specific window. Commonly it is 14 days of the event or of first recognizing the condition, with a detailed written claim following within 21 days. Federal contracts under FAR 52.249-10 impose a 10-day written notice window.2eCFR. 48 CFR 52.249-10 – Default (Fixed-Price Construction) Missing the deadline can forfeit an otherwise valid claim. Some jurisdictions enforce notice strictly, so a notice sent on day 15 instead of day 14 waives the claim regardless of merit. Others apply a substantial compliance standard that looks at whether the owner suffered prejudice from the late notice. The safer move is to give notice immediately and in writing, even before the full scope of the delay is clear. A preliminary notice stating that an owner action appears to be affecting the critical path, with specifics to follow, preserves the right while the analysis catches up.