The job finished six weeks late. The client is holding money back — a fixed sum for every week past the completion date, because that’s what the contract says they can do. Your site manager can tell you exactly what went wrong: the steel came three weeks late, the groundworks sub disappeared for a fortnight, the architect sat on a drawing query while two trades stood around it. He’s right about all of it.
Prove it.
That’s the whole game when a job overruns. Not what happened — what you can show happened. And in most firms I audit, the gap between those two things is where the money goes.
The machinery, in plain English
Most commercial building work in this country is signed on a standard form of contract, and the most common family is JCT — the Joint Contracts Tribunal, the industry body that has published them for decades. A JCT contract fixes a completion date, and behind that date usually sit liquidated damages: a sum agreed before the job starts — so much per week of lateness — that the client can deduct from what they owe you, no court required. Finish late, lose money, automatically.
Your defence is an extension of time: the completion date moves if the delay was caused by something the contract says isn’t your risk. JCT calls these relevant events — the client changing their mind, instructions arriving late, exceptionally bad weather, and a list of others. Delay caused by a relevant event shifts the date, and the damages fall away with it.
But the entitlement doesn’t arrive by itself. The JCT wording requires you to give written notice “if and whenever it becomes reasonably apparent” that the works are being delayed — that is, when you spot it, not months later when the argument starts. And the schedule of amendments stapled to most contracts a mid-market firm actually signs often hardens that duty into a strict deadline: no notice in time, no extension, however good the excuse.
The other big contract family, NEC — common on public-sector and infrastructure work — is blunter still. There, a delay event is a compensation event, and the standard wording gives you eight weeks from when you became aware of it to notify. Miss the window and, with one narrow exception, the entitlement is simply gone. Not weakened. Gone.
Where the evidence lives
Now the uncomfortable part. When I ask a firm to show me the record of a late job, here is what usually exists. A site diary, started conscientiously, that stopped in week three when things got busy — which is precisely when the diary started mattering. A WhatsApp thread that is the true record of the job — photos of the empty steel rack, voice notes about the missing drawing — sitting on personal phones, in a group that still includes a plumber who left in March. Hundreds of photos with nothing tying any image to a date, a location on the job, or a consequence. And the site manager’s memory, which is excellent, and worth very little in writing.
The claim then gets assembled months afterwards, working backwards from the overrun, often by someone who was never on the site. Against it stands whatever the client’s side wrote down at the time. A diary entry made on the day beats a recollection assembled six months later — every adjudicator works that way, and so does common sense. The industry’s own dispute reports have put poor contract administration at or near the top of the causes list year after year, and keeping records as things happen is most of what contract administration is.
You don’t lose because you caused the delay. You lose because you can’t show you didn’t.
A diary, not a planner
The software sold for this problem is project controls: planning suites, scheduling dashboards, portfolio views. Serious tools, built for firms with planners to feed them. A firm with one overworked site manager per job will not feed them, and a record system nobody feeds is a decoration.
What’s actually missing is much smaller. A daily site record that takes two minutes on the phone already in the site manager’s hand: who was on site, what was delivered or wasn’t, what stopped and why, what was asked of the architect and when. Each entry date-stamped, tied to the job, photos attached at the moment they’re taken rather than excavated from a camera roll a year later. The bar for keeping it is simple — it has to be faster than the WhatsApp message it replaces, because that’s what it’s competing with.
And one thing worth building in on top. When an entry says the job is waiting on someone else, the system should ask a single question: has anyone told the client, in writing? Because those notice clocks — JCT’s “reasonably apparent,” NEC’s eight weeks — start running on site, and they run out in the office. The tool doesn’t write the letter. It stops the deadline passing while everyone’s busy.
Where this doesn’t apply
If your work is domestic — extensions and refurbs for homeowners, no formal completion date, no liquidated damages — this isn’t your problem, and you shouldn’t buy anything for it. If you employ a full-time quantity surveyor and planner who already keep proper progress records, you’re covered; don’t duplicate them. And on jobs of a week or two there’s nothing worth recording that an email won’t hold.
The exposure sits exactly where mid-market firms live: contracts running months, signed on amended standard forms, with damages clauses nobody read closely and one site manager holding the whole story in his head. On those jobs, the record either exists by the end of each day or it never really exists at all.
If your last overrun turned into an argument you couldn’t quite win, get in touch.