The real cost of a missed compensation event

A valid £180,000 compensation event can be worth nothing by Friday. Not because the entitlement was weak. Because the eight-week clock in clause 61.3 ran out while the evidence sat in a diary nobody read. The event happened. The cost was real. The right to recover it simply expired.

Every commercial team on an NEC contract knows the time bar exists. Far fewer know what it actually costs when one slips through. This is that number, worked out in full.

What clause 61.3 really does to you

A compensation event is a contract event under NEC4 that entitles the contractor to more time, more money, or both. Weather beyond the tender threshold. A change to the Works Information. An instruction to stop. Ground conditions an experienced contractor would not have allowed for. The NEC4 contract lists them, and on most jobs several occur every month.

Clause 61.3 sets the trap. If the Project Manager has not already notified the event, the contractor must notify it within eight weeks of becoming aware of it. Miss that window and you lose the right to any change in the Prices, the Completion Date, or a Key Date. The clause is blunt about it. The entitlement does not shrink. It vanishes.

There is no discretion to fall back on. A perfectly valid event, fully substantiated, becomes commercially worthless once the eight weeks pass without a notice. Adjudicators enforce this. The bar is not a formality. It is the whole game.

The £180,000 that quietly disappeared

Take a £50 million highways scheme under NEC4 Option C. Nothing unusual about it.

In week three, the client issues a revised drainage layout as a drawing update. On site it looks routine. The gang digs to the new levels, lays the extra pipe run, and works around a service diversion that was not on the original design. The site engineer records it honestly: "Revised drainage layout, continued excavation, standing time on the 360 while UKPN attended."

That entry is a Works Information change. It is a compensation event. Nobody flags it as one.

The direct cost stacks up fast. Extra excavation and disposal, roughly £96,000. Additional pipe and bedding, £31,000. Two weeks of standing time and prolongation on the drainage gang, near £53,000. Call it £180,000 of legitimate, recoverable exposure sitting inside a single fortnight of ordinary site records.

The eight-week clock started the day the team became aware, which was the day they read the revised drawing. Week nine arrives during a busy valuation cycle. The QS is deep in the CVR, the diary backlog is three weeks tall, and the drainage entry never gets read for commercial implications. No notice goes out.

The event is now time-barred. The £180,000 moves silently from recoverable revenue into absorbed cost. On an Option C job it hits the pain share too, so the real damage to the contractor's position is worse than the headline figure. On a typical margin, you would need several million pounds of extra turnover to earn that £180,000 back. One unread diary entry gave it away.

This example is illustrative. The mechanics are not.

Why the diary is the evidence, not the paperwork

Here is the part commercial teams underrate. The compensation event was never invisible. It was recorded, in full, on the day it happened. The failure was not capture. It was that nobody connected a routine site diary entry to a clause 61.3 obligation before the clock ran out.

This is the pattern behind almost every missed CE. The evidence exists. It is contemporaneous, it is detailed, and it is buried. A site diary is the single most important commercial document on an NEC job, because it is the only record created at the time, by the people who were there, before anyone knew it would matter. When a CE reaches assessment or dispute, the diary is what proves the event happened, when awareness began, and what it cost.

Scattered records break that chain. When the diary lives in a notebook in a site vehicle, half in WhatsApp and half in a spreadsheet called Final_FINAL_v3, two things fail at once. You cannot spot the event in time to notify it. And even if you do, you cannot prove awareness, sequence, or cost when the other side pushes back. The time bar and the evidence gap are the same problem wearing two hats.

Structured, searchable, tamper-evident records fix both. Every entry timestamped and GPS-tagged. Every event visible against the contract. The eight-week clock starting from a date you can actually defend.

See where your own time bars are running. Gather's QS AI Agent reads every diary entry against your contract and flags likely compensation events before the clause 61.3 window closes, with a countdown on each one. Book a 30-minute demo and we will show you how it works on a real project.

The mistakes that cost the most

Three failures show up again and again on missed CEs.

The first is treating diary review as a junior task. Manual review usually falls to an apprentice or a junior QS who is diligent but lacks the experience to see that "revised drainage layout" is a Works Information change. The commercial reading only happens months later, during final account prep, when the notice periods have long closed.

The second is reviewing on a monthly cycle. A CE noticed in a month-end review can already be four or five weeks into its eight-week window. On anything with a lag, you are notifying against the clock or missing it outright. The event needs reading the week it is recorded, not the month.

The third is confusing communication with capture. Teams assume that because the drawing came through a formal channel, the commercial consequence is handled. It is not. A CEMAR or Contract Bee notice proves what you told the client. It does not prove what happened on the ground, and it does not raise itself. The obligation to spot the event and start the clock still sits with you.

What good looks like

Contractors who rarely miss a time bar do three things differently.

They read every diary entry for commercial meaning, not just progress. They do it continuously, not monthly. And they keep records structured enough that awareness, sequence, and cost can be evidenced without a two-day hunt.

That is a lot to ask of a commercial team already stretched across several projects. Reading 100% of entries within days of capture, against the contract, on every job, is not realistic by hand. It is exactly the kind of relentless, unglamorous review that software does well and tired humans do badly at 6pm on a Friday. The QS AI Agent identifies around 40% more compensation events than manual review, precisely because it never skips the boring entries where the expensive ones hide.

Frequently asked questions

What is the time bar on a compensation event under NEC4?

Under NEC4 clause 61.3, the contractor must notify a compensation event within eight weeks of becoming aware of it, unless the Project Manager has already notified it. Miss the eight weeks and you lose entitlement to any change in the Prices, the Completion Date, or a Key Date, regardless of how valid the event was.

Can you recover a compensation event after the 8 weeks have passed?

Generally no. If the event should have been notified by the contractor and was not notified within eight weeks, clause 61.3 removes the entitlement. The event does not carry over into the final account. This is why spotting the event early, from contemporaneous records, matters far more than assembling evidence later.

How much can a single missed compensation event cost?

It depends entirely on the event, but six-figure losses are common on major projects. A single change to the Works Information affecting a few weeks of work can carry £100,000 or more in direct cost, prolongation, and disruption. Under a target contract, a missed CE also erodes the pain and gain position, so the real impact is often larger than the headline figure.

Why are site diaries so important for compensation events?

The site diary is usually the only contemporaneous record of what happened, when the team became aware, and what it cost. It establishes the start of the eight-week clock and substantiates the event at assessment or in dispute. Without a clear, timestamped diary, you struggle to spot the event in time and to prove it later.

How does Gather help contractors avoid missing compensation events?

Gather captures structured site diaries and its QS AI Agent reviews every entry against your contract in real time, flagging likely compensation events and early warnings with a countdown to the clause 61.3 deadline. It reads 100% of records continuously, so events surface within days of being recorded rather than months later.

The bottom line

A missed compensation event is not a small administrative slip. It is six figures of earned revenue handed back because an entry was recorded but never read in time. The evidence was there. The clock beat you to it.

Fix the review, not just the capture. Read every diary entry for commercial meaning, do it within days, and keep records you can defend. If you want to see how much time bar exposure is sitting in your current projects, book a demo of the QS AI Agent and we will run it against a live job.

Source: Gather Insights, the AI-powered site diary and commercial record management platform for UK construction.