One significant cause the claimant cannot exclude can sink a global claim in Australia

Every commercial manager has felt the temptation. The project lost money; the principal caused chaos all year; untangling which event caused which dollar looks impossible. So the claim becomes: here is everything that happened, here is our total overrun, the connection is obvious. That is a global claim, and in Australia it is the closest thing claims practice has to a known losing strategy. Understanding precisely why tribunals reject them is the best available training in what a winning claim looks like.

A global claim alleges a composite loss from multiple events without demonstrating the causal link between each event and any specific portion of the loss. In John Holland Construction & Engineering Pty Ltd v Kvaerner RJ Brown Pty Ltd (1996) 8 VR 681; 82 BLR 81, Byrne J urged “a great deal of caution, even distrust” in approaching a total cost claim (at [23], as quoted in Mainteck at [192]). The commonest species of global claim is the total cost claim: actual cost minus tender, with the whole gap attributed to the other side.

Kvaernerremains the leading Australian statement. Global claims are not absolutely prohibited, but they attract close scrutiny, and the total-cost variant requires the claimant to prove four things: that it could reasonably have performed within its tender allowance; that the defendant's events caused additional cost; that actual costs exceeded the allowance; and, the killer, that the defendant's events were the only causally significant factor in the overrun.

The New South Wales Court of Appeal hardened the position in Mainteck Services Pty Ltd v Stein Heurtey SA[2014] NSWCA 184: there are no special causation rules for construction cases, the claimant must exclude all other operative causes, and it cannot recover the whole claim, or an apportioned share, merely by proving that some breaches caused some loss ([182]). In a global claim, “a significant cause of loss not attributable to the defendant is fatal” ([205]). DM Drainage & Constructions Pty Ltd v Karara Mining Ltd [2014] WASC 170 makes the logic explicit: without excluding alternative causes, the causal inference simply cannot be drawn (at [59]).

This is materially stricter than the English position. In Walter Lilly & Co Ltd v Mackay [2012] EWHC 1773 (TCC), Akenhead J held a claimant-caused contributing event merely reduces the global sum rather than dooming the claim. In Australia, post-Mainteck, the contaminating cause can defeat the lot. Importing Walter Lilly optimism into an Australian dispute is a category error.

And the attack can come before trial. Wharf Properties Ltd v Eric Cumine Associates (No 2) (1991) 52 BLR 1 is the case usually cited for striking out an unparticularised global claim (see Walter Lilly at [476]). Built Environs WA Pty Ltd v Perth Airport Pty Ltd [No 2] [2019] WASC 76 struck out causation paragraphs of a design-deficiency claim as embarrassing (at [56]); in Built Environs WA Pty Ltd v Perth Airport Pty Ltd [No 3] [2019] WASC 399 the court refused leave to replead, because the deficiencies were still not linked to extra hours or costs (at [101] to [111]).

Global claims can succeed. In Decor Ceilings Pty Ltd v Cox Constructions Pty Ltd (No 2) [2005] SASC 483, a subcontractor held on site some 22 weeks beyond its 15-week contract period ran global claims. On appeal, the estimator's own evidence of his tender build-up was enough to prove the first element, and all four elements were made out ([98] to [99], [101]). The exception is instructive: it succeeded because it stopped being lazy.

Strip the doctrine away and global claims fail for four practical reasons.

1. 01

   The causation gap. The inference from “many events” to “this loss” collapses the moment the respondent points to any cause the claimant owns: weather, its own rework, an underpriced tender.

2. 02

   Self-contamination. In a total cost claim, the claimant's own inefficiencies are necessarily buried in the global sum, and in Australia that can be fatal rather than merely deductive.

3. 03

   The unproven baseline. The tender must itself be proved adequate: the very thing a money-losing project makes doubtful.

4. 04

   Forensic surrender. Presenting a global claim tells the tribunal the claimant either lacks the records to do better or chose not to use them. Walter Lillyitself warns tribunals may be “more sceptical” where direct linkage was available and not deployed.

The alternative is not heroic. It is structural, and it starts during delivery, not at claim time.

• Disaggregate by cause, not by month. Build the claim event-by-event: this RFI delay, these affected activities, this window of prolongation, these costs. Where events genuinely interact, group them into the smallest defensible clusters and explain the interaction. A reasoned composite for two intertwined causes is a different animal from a project-wide global sum.
• Run the delay-event register from day one. Cause ownership assigned in real time (principal-risk, contractor-risk, neutral) is precisely the evidence that lets you exclude alternative causes later: the Mainteck requirement that kills claims assembled retrospectively.
• Segregate costs while they're being incurred. Cost codes per event or work front for disrupted work, daywork records for changed work, time-related preliminaries tracked by period. The measured-mile and prolongation methods we cover separately all depend on this granularity.
• Prove the baseline early.Keep the tender build-up, productivity allowances and their basis. If the claim ever has to defend the proposition “we would have made money but for these events”, the estimator's contemporaneous workings are the foundation (Decor succeeded on exactly this).
• If cornered into a composite claim, do it the hard way. Plead the claim type honestly, identify every causative event, demonstrate the exclusion of your own causes item by item, and carve out everything that can be directly linked. The Built Environs strike-out is the cost of skipping those steps.

Get advice before you serve or plead a claim that rolls several events into one overrun, when you are asked to answer one, and early in delivery when the records that will have to prove cause and cost are being set up. The answer turns on your contract, your records and the forum.