Can a string of WhatsApp messages really form a legally binding construction contract worth nearly a quarter of a million pounds?

In a decision that highlights the legal weight of informal communications and the practical realities of construction contracting, the Technology and Construction Court (TCC) in Jaevee Homes Limited v Mr Steve Fincham (trading as Fincham Demolition) [2025] addressed a dispute over whether a contract was formed via WhatsApp messages and whether subsequent invoices constituted valid payment applications under the Housing Grants, Construction and Regeneration Act 1996 (the Construction Act).

In this article, we summarise the key takeaways from the decision, including how informal communications can form legally binding contracts and the payment rules under the Construction Act and the Scheme for Construction Contracts.

We also share six practical tips to help construction professionals manage risk during early stages of negotiation.

Case summary: Jaevee v Fincham [2025]

The dispute arose from demolition works at a former nightclub in Norwich. Following initial site visits and a formal written quotation from the Defendant, the Defendant and the CEO of the Claimant engaged in a series of WhatsApp messages. The WhatsApp messages addressed key commercial terms, including the job award, a lump sum price of £248,000, and a proposed structure for monthly invoicing with 28–30 day payment terms. Whether this informal exchange gave rise to a binding contract was a central issue in the proceedings.

Following the WhatsApp exchanges referred to above, the Claimant emailed the defendant attaching a formal short form subcontract which set out the agreed contract sum of £248,000, payment terms and the Claimant's standard terms, including further provisions for extensions of time, variations, and liquidated damages. The Defendant did not respond to the Short Form Subcontract, but commenced works shortly afterwards.

Following commencement of works, the Defendant issued four invoices (all within short intervals spanning a seven week period). The Claimant made partial payments totalling £80,000 but disputed the validity of the invoices, arguing they did not comply with its requirement for monthly applications.

In July 2024, the Defendant commenced adjudication proceedings, seeking payment of outstanding invoices on the basis that no pay less notices had been served. The Adjudicator found in the Defendant's favour, awarding £145,896.31.

When the Claimant failed to pay, the Defendant initiated enforcement proceedings in the TCC. The Claimant subsequently issued Part 8 proceedings, seeking declarations that the invoices were invalid and that the contract was governed by its own standard terms.

Thus, the question was raised; which terms governed the parties' contractual relationship – the terms of the short form subcontract or those set out in the What's App exchange?

What was the Claimant's position in Jaevee v Fincham [2025]?

The Claimant contended that:

  • the Defendant had accepted the short form subcontract by conduct when it commenced work. Under this framework, the Defendant's invoices were invalid because they failed to comply with the subcontract’s requirements for interim payment applications, including timing, format, and supporting documentation; or
  • alternatively, if the contract had been formed via the earlier WhatsApp messages exchanged —then the submission of multiple invoices within short intervals breached the agreed requirement for monthly payment applications. It also challenged the validity of the invoices under the Scheme for Construction Contracts, asserting that they lacked sufficient detail to constitute valid payment or default notices.

What was the Defendant’s position in Jaevee v Fincham [2025]?

The Defendant argued that:

  • a binding contract was concluded through the exchange of WhatsApp messages which confirmed the award of the job, a lump sum price of £248,000, and a payment structure based on invoices payable within 28–30 days. This informal exchange reflected the parties’ true intentions and had sufficient clarity of terms to constitute a settled contract between the parties;
  • the invoices submitted were valid applications for payment under the agreed terms and, in the absence of pay less notices, became payable under the statutory scheme. They provided sufficient detail, especially in the context of a lump sum contract, and the Claimant's internal communications had acknowledged them as payment applications. The Scheme for Construction Contracts filled any procedural gaps, and the court should adopt a practical, common-sense approach.

What was the TCC's decision in Jaevee v Fincham [2025]?

The TCC affirmed the Adjudicator’s decision and held that:

  • A binding contract was formed through an exchange of WhatsApp messages between the Defendant and the Claimant, which evidenced agreement on the key terms. The Court rejected the Claimant’s argument that the contract was governed by the formal subcontract issued later, stating: “the exchange of WhatsApp messages, whilst informal, evidenced and constituted a concluded contract”.
  • The Court accepted the Claimant’s submission that the agreement between the Parties provided for only one application per month. Although the contract lacked sufficient detail on how payments were to be calculated, the Court reminded the parties that "the absence of payment terms is not antithetical to the existence of a concluded contract – an important target of the 1996 Act is to fill the gap if a contract does not contain appropriate payment terms."

The court therefore refused to grant the declarations sought by the Claimant, holding that three of the four invoices submitted by the Defendant were valid applications for payment.

Guidance for construction professionals

This judgment highlights the risks of relying on post-agreement formalities to define the legal relationship. It also clarifies a broader concern: when payment mechanisms are left vague or undocumented, the Scheme for Construction Contracts will step in — with potentially significant consequences.

Some practical pointers:

  1. Contractors and developers should mark informal communications as “subject to contract” during negotiations: otherwise, they may be legally interpreted as binding agreements.
  2. If a party intends to rely on standard terms, these must be incorporated at the point of contract formation: sending them after agreement has been reached may be ineffective.
  3. Clearly define both when payments are due and also how they are to be calculated: this helps avoid defaulting to the statutory scheme and reduces the risk of disputes.
  4. Make sure both parties formally sign the contract and fully understand its terms: this ensures clarity and enforceability.
  5. Specify which documents form the contract and exclude prior discussions: using an “entire agreement” clause helps ensure only the agreed terms apply, reducing confusion and legal risk.
  6. Train all team members, especially newer colleagues, on the risks of using informal platforms like WhatsApp: these can unintentionally alter contract terms, create confusion due to casual language or incomplete message trials, or breach compliance due to poor record-keeping.

To discuss the issues raised in this article further, please contact Jessica Tresham or Olivia Maurier.

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