Can you control WhatsApp groups on construction sites?

Short answer: not in the way most people mean. You will not police who types what into a group of forty people, half of whom do not work for you. What you can control is narrower and far more useful. You can decide which groups are in scope, say plainly that what goes into them is a project record, and put something in place that copies the instruction and the photograph into a record you own, at the moment it is sent.

That distinction matters because the alternative, a policy that tells people to stop, is the one approach that reliably fails. It does not stop the messages. It stops you seeing them.

Why WhatsApp won, and why that is not a failure of discipline

It is tempting to treat site WhatsApp as laziness. It is not. It won on friction, and on a construction project friction is the whole argument.

There is no login. No licence to buy, no seat to allocate, no training session, no password reset at seven in the morning when the concrete is on its way. The app is already on the phone and already holds the number of every person on the job. A photograph takes two taps and arrives immediately, at a size that works on a site signal, with no question about whether the recipient can open it. A voice note works with gloves on.

Then there is who is actually in those groups, which is the part that project systems keep getting wrong. A commercial platform can be rolled out to your own staff. It is rarely rolled out to the groundworks gang, the scaffolder’s foreman, the steel erector two tiers down, the plant hire desk, the concrete supplier, the client’s facilities manager who wants to see the riser before it is boarded. Those people are on the job and they are in the chat. They will never be given a seat in your system, and per seat pricing is part of the reason why.

So the traffic sorts itself into layers. Directors and commercial managers use it for speed between themselves. Project managers use it to reach people who are not at a desk. Site managers use it downward to gangs and outward to subcontractors. Gangs use it between themselves and upward when something is in the way. Every one of those layers is moving information that would once have been a letter, a site instruction or a minuted decision.

What is actually passing through those groups

On most projects, more than anyone has admitted in writing. In practice it is:

• Instructions to proceed, including work that is plainly a variation and is never confirmed as one.
• Answers to what are really RFIs and technical queries, given as a photograph of a marked up drawing with a line of text under it.
• Approvals and acceptances: a mock up signed off, a setting out agreed, a substitution allowed.
• Programme direction. Move to level three, leave the cores, come in Saturday.
• Health and safety decisions, including the ones taken quickly when something is found in the ground.
• Commercial positions: prices agreed, rates confirmed, dates for completion accepted, all of it in a thread that nobody exports.

The uncomfortable part is not that this happens. It is that it is usually the most contemporaneous and most honest record on the project, and it is held on personal phones belonging to people who may have left by the time it matters.

The law has caught up, and it is not close

The case that settles the argument in this country is Jaevee Homes Ltd v Fincham (t/a Fincham Demolition) [2025] EWHC 942 (TCC). A demolition contractor and a developer discussed a job on WhatsApp. On 17 May 2023 the contractor asked, in substance, whether the job was his so he could start getting organised. The reply was one word: yes.

The Technology and Construction Court held that this was offer and acceptance, and that a binding contract was formed at that point. A formal sub-contract was emailed nine days later, at a different figure and with a monthly payment regime. The other side never acknowledged it, and it was not incorporated. Around £195,000 was invoiced, £80,000 was paid, and the balance was fought over in court on the basis of a contract that existed only in a phone.

Nothing about that is a novelty of the digital age. English law has never required a construction contract to be in a particular form, and offer, acceptance, consideration and an intention to create legal relations can all be found in a chat thread as readily as in a letter. What has changed is that the thread is now where the conversation actually happens.

Two further points are worth holding on to.

Informality is not a defence, and neither is brevity. In Canada, in South West Terminal Ltd v Achter Land & Cattle Ltd, 2023 SKKB 116, a thumbs up emoji sent in response to a contract was held to be acceptance of it, and the sender was ordered to pay around 82,000 Canadian dollars. The court asked what a reasonable person would understand the reply to mean. That is the same question an English court asks, which is why the case gets quoted here so often. A reaction is a reply.

Deleting the thread is worse than keeping it. Messages are disclosable in litigation and routinely produced in adjudication, and that includes messages on personal devices used for work. In Ocado Group plc v McKeeve a solicitor was found in criminal contempt of court and fined £25,000 for telling a contact to delete a messaging application after a search order had been granted. Whatever the thread contains, destroying it converts a commercial problem into a conduct problem.

The pattern is not confined to England. Courts in South Africa, Singapore, Australia, India and the Gulf have all had to decide what weight to give messaging app exchanges, and while the answers differ on evidence and formality rules, the direction is consistent: the fact that a conversation was convenient does not make it casual.

Why the ban does not work

Most contractors have tried one. It usually survives about a fortnight, for three reasons.

The first is that the ban is unenforceable against the people who are not yours. You cannot discipline a supplier’s driver or a subcontractor’s foreman for sending a photograph, and they are the ones who send most of them.

The second is that the alternative is slower at exactly the moment speed matters. Nobody opens a laptop to ask whether the rebar has arrived.

The third is the one that actually hurts. A ban does not remove the messages. It removes your ability to say where they are. The conversation moves to individual chats and personal numbers, and when a dispute arrives eighteen months later you are asking former employees to search their own phones for something that may cost them nothing to lose and you a great deal.

What control actually looks like

Control here means five things, and none of them is a rule telling people to stop.

1. Scope. Decide which groups are project groups. Name them. A group for the job is a record. A group for the five a side is not.
2. Notice. Tell everyone in writing, once, that messages in the project groups are project records, may be retained, and may be produced in a dispute. This costs nothing and changes how people write.
3. A single place decisions live. A message can start a decision. It should not be the only place the decision exists. If it is an instruction, it becomes an instruction. If it is a variation, it gets confirmed as one. The thread is the trigger, not the filing system.
4. Capture that does not rely on anyone remembering. This is the part people skip, and it is the part that decides whether any of the rest survives contact with a busy Thursday. If capturing the message into the record is a second job done by hand, it will be done for a fortnight and then it will not.
5. Retention. Messages and their media kept for the life of the project and the limitation period after it, with dates, senders and originals intact. A screenshot pasted into a Word document months later is not the same thing, and the other side will say so.

How we approach it

Construction Metric was built around this exact problem. The listener sits in the project WhatsApp groups and takes what is said into the record as it happens: the message, the photograph at full resolution, who sent it, and when. It sorts the traffic into site diary entries, and it keeps the original alongside, so what you produce later is a contemporaneous record rather than a reconstruction.

Nobody on site is asked to change what they do. That is the design constraint the whole thing is built to, because every system that asks a site manager to do the same job twice has already lost. There is more detail on how the WhatsApp capture works, and on turning the record into evidence when something becomes a claim.

Two related pieces cover the questions that follow this one: whether WhatsApp messages are admissible and whether a photograph alone carries a daywork claim.

This is not only a construction problem

It is worth knowing how other industries have handled the same thing, because construction is late to it rather than unlucky.

Financial services went first, and it was expensive. Regulators took the view that business conducted on unmonitored channels breached recordkeeping rules, and enforcement followed: in the United States, penalties for off channel communications have run past three billion dollars across more than a hundred firms since 2021, with a further round of settlements in January 2025. The firms were not accused of fraud in those cases. They were penalised because the conversation happened somewhere the record could not reach.

Automotive and manufacturing have the same exposure in a different shape. Engineering changes, supplier deviations and concessions agreed in a chat and never fed into the change record are the ones that surface during a recall investigation, when the question is who approved the departure and when.

Journalism sits at the other end of it. Newsrooms rely on messaging for source contact precisely because it is encrypted and immediate, and then have to answer for what was promised to a source, or produce the exchange in a defamation claim, from an app designed to leave little behind.

Healthcare, logistics, legal practice and the public sector have all arrived at the same question. The answer that works is consistently the same: stop fighting the channel people choose, and put a record behind it.

Questions and answers

Where to start

If the honest position on your projects is that the real record is on people’s phones, that is worth fixing before it is tested. We build this for UK contractors and consultants at AI Metric, and Construction Metric is the product that came out of it. If you want to talk it through against your own contracts and your own projects, get in touch and we will look at it properly.