Concurrent delay occurs whenever two or more separate events – at least one of which is an employer risk event and at least one a contractor risk event – independently delay the critical path of a project.
The substantial majority of standard form construction and engineering contracts are silent as to either the definition of or apportionment of responsibility for concurrent delays, and it is generally rare for parties to seek to include language to that effect by way of bespoke amendment. This reluctance to legislate for concurrent delay in contracts probably reflects the inherent difficulty in formulating language that would adequately address what is always a complex and necessarily heavily fact-dependent issue.
Nevertheless, the consequence of this widespread lack of contractual language is that issues concerning concurrent delays are usually left to be determined by the law of the contract.
Traditionally, the cases raising concurrency in the Courts of England and Wales have concerned concurrent delays by a contractor that is claiming an extension of time against an Owner. In the seminal case, Henry Boot Construction (UK) Ltd v Malmaison Hotel (Manchester) Ltd  70 Con. L.R. 32, the Court recognized that in such a situation the Contractor would be entitled to an extension of time but not to prolongation costs.
The determination of what is required for two delays to be concurrent under English law, however, has remained unclear.
The preferred approach, the “dominant cause approach”, assigns liability to whichever delay is the “effective, dominant cause” of the critical path impact. If there is such a dominant cause, the delays are not concurrent; concurrency occurs only when both delays are of “approximately equal causative potency.” North Midland Building Ltd v Cyden Homes Ltd  EWCA Civ 1744; H. Fairweather & Co Ltd v London Borough of Wandsworth  39 BLR 106 (OR).
A contrary line of cases, however, has resolved apparently concurrent delays based on a first-in-time approach under the reasoning that a subsequent concurrent delay does not actually effect the completion date of the Works: Royal Brompton Hospital NHS Trust v Frederick A Hammond & Ors . Under this approach, true concurrency would require that “both events in fact cause delay to the progress of the works and the delaying effect of the two events is felt at the same time.” Id. Note that this approach does not require the events themselves to be concurrent, only the effects of those events.
This view has seemingly been dominant in recent years, having been adopted in Adyard Abu Dhabi v SD Marine Services  EWHC 848 (Comm) (11 April 2011) and Saga Cruises BDF Ltd v Fincantieri SPA  EWHC 1875 (Comm) (29 July 2016).
This approach has also been recommended in the Second Edition of the Society for Construction Law’s Delay and Disruption Protocol, but was condemned by Scotland’s courts as “unnecessarily restrictive and [an approach] which would militate against the achievement of its obvious purpose of enabling the architect, or other tribunal, to make a judgment on the basis of fairness and a common-sense view of causation.” City Inn Ltd v Shepherd Construction Ltd  CSOH 190 (30 Nov. 2007) – a judgment that was itself criticized in Walter Lilly & Co. Ltd v Mackay  EWHC 1773.
The contrasting approaches adopted by the Courts in this regard undoubtedly reflect the fact that whilst the Courts recognize that this is an area that requires judicial guidance, it is also heavily fact-dependent, such that an approach adopted in one case may not be appropriate with a different set of facts.
Insofar as it is possible to establish overarching principles, they are likely to be those summarized in Saga Cruises v Fincantieri and drawn from Henry Boot v Malmaison:
- Where an employer risk event actually causes a delay to completion, the contractor will always be entitled to an extension of time notwithstanding any concurrent contractor risk events. This is based in part on the principle that an employer cannot hold a contractor to an obligation that the employer himself has prevented the contractor achieving (the “prevention principle”).
- The delay caused by an employer risk event must be actual, not notional or theoretical.
- Where a contractor risk event has caused concurrent delay, the contractor’s claim for prolongation costs arising from the employer risk event is likely to fail for want of causation.
- In cases of concurrency, the Courts (and therefore contract administrators) should be very cautious to attempt to apportion critical delay between two or more concurrent events.
Notwithstanding these principles, the treatment of concurrency remains uncertain, especially under international contracts where the law of England and Wales is being applied by an external tribunal or arbitrator.
It is thus noteworthy that last week the TCC rendered a decision addressing concurrent delays: Thomas Barnes & Sons PLC v Blackburn with Darwen Borough Council  EWCH 2598 (TCC) (17 Oct. 2022). The Borough Council for the borough of Blackburn with Darwen (“Blackburn”) contracted with Thomas Barnes to construct a bus terminal under the terms of a Joint Contracts Tribunal agreement. The subsequent litigation stemmed from Blackburn’s denial of Barnes’ extension of time claims and termination of the Contract based on delays to the Works.
Barnes’ extension of time claim was based on structural steel defects (deflection under load) for which Barnes was not contractually responsible. Completion of the structural steel work was necessary to allow pouring of the concrete topping, which in turn was required for exterior wall construction and interior finishing thereafter. While the structural steel delays were ongoing, Barnes independently suffered delays to its roof works, which were also a required prerequisite to interior finishing. The roof delays, however, arose after the structural steel delays, and were resolved prior to the construction of the exterior walls, and therefore did not independently cause delay to the critical path.
The Court found that these roof delays, although subsumed entirely within the critical path impact of the structural steel delays, were concurrent, writing:
“In my judgment this is a case where these causes were concurrent over the period of delay caused by the roof coverings. That is because completion of the remedial works to the hub structural steelwork was essential to allow the concrete topping to be poured and the hub SFS to be installed, without which the hub finishes could not be meaningfully started, but completion of the roof coverings was also essential for the hub finishes to be meaningfully started as well. It is not enough for the claimant to say that the works to the roof coverings were irrelevant from a delay perspective because the specification and execution of the remedial works to the hub structural steelwork were continuing both before and after that period of delay. Conversely, it is not enough for the defendant to say that the remedial works to the hub structural steelwork were irrelevant from a delay perspective because the roof coverings were on the critical path. The plain fact is that both of the work items were on the critical path as regards the hub finishes and both were causing delay over the same period.”
The Court held that Barnes was entitled to an extension of time based on the delay caused by the steel frame deflection, but was only entitled to prolongation damages for the periods of delay that were not concurrent with Barnes’ own delays to the roof works.
Even given the diversity of approaches taken by the Courts on concurrency this is a curious decision. On the facts as given in the judgment, it appears that the dominant cause of delay was the completion of remedial works to the hub structural steelwork, and that this is therefore not an instance of true concurrency. However, the Court does not discuss the dominance of these works, and it is possible that this issue was not raised in submissions before it. The Court also appears to have ascribed at least some significance to the parties’ contemporaneous evaluation of the critical path impacts of the two delays, a consideration that has not played a prevalent role in prior decisions addressing concurrent delays.
It is not currently known whether this decision will be appealed. Nevertheless, in the meantime this case only increases the uncertainty surrounding the definition of “concurrent delay” under the law of England and Wales.
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