The WhatsApp judgment: what Jaevee v Fincham means for your site records

What did the court actually decide?

On 16 April 2025 the Technology and Construction Court handed down judgment in Jaevee Homes Limited v Steve Fincham, and it settled a question the industry had been avoiding for years: yes, a contract can be formed over WhatsApp, and yes, it will be enforced.

Jaevee engaged Fincham Demolition to demolish a former nightclub in Norwich. There was no signed contract when the work began. There was a WhatsApp exchange, and Mr Roger Ter Haar KC held that the exchange on 17 May 2023 was the contract: the job confirmed, and payment terms of 28 to 30 days from invoice. The court went on to find the contract price to be 248,000 pounds. The formal subcontract that Jaevee emailed afterwards had never been accepted, so it was never incorporated. The terms that governed were the ones typed into a phone.

Jaevee paid 80,000 pounds of the 195,857 pounds invoiced and withheld the balance without serving pay less notices. The adjudicator had already ruled for Fincham on that basis, and the court proceedings that followed largely confirmed the position.

Which part should actually worry you?

Not the headline. The interesting finding is quieter, and it is about timing. The court held that the contract ran on monthly payment cycles from 17 May 2023, and then tested each invoice against that cycle. Three of the four were valid payment applications under the Housing Grants, Construction and Regeneration Act 1996. One was not, and it failed for a purely structural reason: it was a second application inside the same monthly period.

So the messages did not just create a contract. They fixed a payment cycle that nobody sat down and negotiated, and that cycle then decided which invoices counted. A payment mechanism assembled by accident, out of a conversation, is still a payment mechanism you are bound by.

What has this got to do with the Building Safety Act?

Directly, nothing. This is contract formation and payment under the Construction Act, not a higher-risk building case, and anyone telling you it changes your gateway duties is selling something. We cover it here because it proves something this site argues on every evidence page: the messages your team sends from site are records, and records have consequences you did not choose.

The Building Safety Act supplies the regulatory version of the same problem. Your change control log has to explain every departure from the Gateway 2 approval. Your as-built golden thread has to describe the building that exists. The BSR names weak change records and as-built discrepancies among the reasons completion applications stall, and in practice the decisions behind those discrepancies were usually made in a thread on somebody's phone.

Jaevee simply removes the last comfortable excuse for treating that thread as informal. A message that can form a 248,000 pound contract is not chatter.

What changes on Monday?

Three things, none of which require anybody to stop using WhatsApp, because they will not.

Decide who can commit you, and tell them. The exposure in Jaevee was not the app, it was a senior person agreeing scope and price in a medium nobody treated as contractual. Authority limits that exist only in a procedures manual do not survive a busy Tuesday.

Assume every thread is disclosable and write accordingly. The realistic test is not whether a message feels formal. It is whether you would be content to read it aloud in a hearing eighteen months from now, with the surrounding messages read out too.

Keep the record, not just the conversation. Phones are replaced, group chats are left, and a thread that cannot be produced complete is worth very little when the argument arrives. That is true for the commercial argument Jaevee was about, and it is true for the evidence a Gateway 3 application rests on.

One closing note on how to read this. The court did not rule that WhatsApp is a good way to contract. It ruled that the ordinary tests, offer, acceptance, consideration and intention, apply to whatever medium you happen to use. The medium was never the point. What you typed was.