The judgment in Piperhill Construction Limited v Northern Ireland Housing Executive [2025] NIKB 47 considers the obligation to pay the Notified Sum. In these proceedings, Piperhill Construction Limited (plaintiff) sought summary judgment in the Northern Irish High Court to enforce an adjudicator’s decision. The Northern Ireland Housing Executive (defendant) resisted the application and argued that the adjudicator had no jurisdiction.

The plaintiff and the defendant had entered a contract in August 2022 for the refurbishment of social housing. In March 2025, the plaintiff served a notice of adjudication alleging: (1) that the defendant had failed to pay the sum specified in the plaintiff’s application for payment in February 2025 (Notified Sum); and (2) that the pay less notice, served by the defendant, did not comply with the construction contract. As such, the notice was said to be invalid and of no legal effect. The adjudicator held for the plaintiff finding that there had been a failure to comply with the terms of the construction contract by the defendant.  As such, the defendant was said to be liable to pay the Notified Sum.

The defendant refused to make payment, and the plaintiff sought summary judgment to enforce the adjudicator’s decision. The plaintiff argued that the adjudicator had jurisdiction to determine the validity of the pay less notice and other relevant documents pursuant to: (1) the notice of adjudication; and (2) the Construction Contracts (Northern Ireland) Order 1997 (1997 Order). The defendant disputed the jurisdiction of the adjudicator to make the award. The core of the argument was that the scope of the dispute referred to the adjudicator was restricted to the issue of issuing a valid pay less notice and that it did not encompass the failure of the defendant to pay the Notified Sum. In considering this argument, Humphreys J reasoned that even if this were the case, the defendant had put the validity of the notice, and therefore the failure to pay at issue, by making the argument that there were no defects in the pay less notice.  Accordingly, the remit of the adjudication was extended to consider the failure of the defendant to pay the Notified Sum.

Humphreys J then examined the arguments in the context of what a reasonable person:

… with all the background knowledge available to the parties at the time, would have understood the words in the document to mean.

In reviewing the arguments, Humphreys J agreed that while the notice of adjudication focused solely on the issue of service of the pay less, the dispute, however, now extended beyond this question to include the defendant’s alleged failure to pay the Notified Sum. As a result, the validity of the pay less notice was crucial to the adjudicator’s decision and the adjudicator had to determine whether, as a matter of law, the pay less notice complied with the construction contract and the 1997 Order.

The Court held that the notice of adjudication included both the issue of the contents of the pay less notice and its respective validity. Consequently, Humphreys J held that the adjudicator was acting within the notice of adjudication and, as such, had jurisdiction to make the award. The Court upheld the adjudicator’s award and ordered the defendant to pay the plaintiffs’ costs.

The judgment reaffirms the high threshold required to interfere with an adjudicator’s decision. Indeed, in the High Court, Humphreys J drew on Carillion Construction Ltd v Devonport Royal Dockyard Ltd [2006] BLR 15, where the Court of Appeal provided that:

The objective which underlies the Act and the statutory scheme requires the courts to respect and enforce the Adjudicator’s decision unless it is plain that the question which he has decided was not the question referred to him or the manner in which he has gone about his task is obviously unfair.  It should be only in rare circumstances that the courts will interfere with the decision of an adjudicator.

The judgment provides a timely reminder that the decision of an adjudicator will be enforced in the vast majority of cases.