The FIDIC 28-Day Rule: Why Timing Kills More Claims Than Merit
This guide unpacks the FIDIC 28-day rule under the 1999 Red Book: what it is, when the clock actually starts, what happens when you miss it, and the tracking habits that keep a Contracts Engineer's weekends intact. Whether you are a Project Manager writing your first notice or a Claims Consultant auditing an old project, this is the practical breakdown.
What Is the 28-Day Rule?
The 28-day rule is the headline deadline for submitting a notice under FIDIC Clause 20.1. Once the Contractor becomes aware (or should have become aware) of an event that might entitle them to extra time or money, the clock starts ticking. Twenty-eight calendar days later, the deadline lands — and with it, the right to pursue that particular claim.
The rule has three moving parts worth separating:
- The trigger — awareness of the event
- The duration — 28 calendar days (not working days)
- The consequence — missing it bars the claim entirely under the strict wording of the 1999 Red Book
Lawyers describe it as a "condition precedent," which is legal language for "do this first or nothing else counts." Your claim might be rock-solid on merit — fully documented, undeniably the Employer's fault, backed by every site photo you have ever taken. None of that matters if the notice was late. The 28-day rule does not care about fairness. It cares about dates.
One wrinkle: FIDIC's newer 2017 2nd Edition builds several procedural steps around the same 28-day core. The notice requirement itself is retained, but three practical changes are worth knowing.
First, the Engineer now has 14 days to issue a rejection if the notice appears to be out of time; if no rejection comes in that window, the notice is deemed valid. That is a meaningful softening of the 1999 strictness.
Second, the detailed claim deadline extends from 42 days to 84 days, reflecting the reality that proper substantiation often takes longer than six weeks. Third, a more structured Engineer's agreement or determination process follows, with its own sub-deadlines and a clearer escalation path.
The substantive logic has not changed — the 28-day clock still starts at awareness, and missing it still puts the claim at serious risk. But the stage-gates around the clock are tighter and apply to both parties, not just the Contractor.
If your contract is 1999 Red Book, plan around a single hard deadline. If it is 2017, plan around the same 28 days followed by a more procedural exchange.
Key Takeaway: The 28-day rule is a condition precedent — a hard contractual gate. Miss it and even the strongest claim on merit can be thrown out, regardless of how fair that feels.
When Does the Clock Start?
The phrase buried in Clause 20.1 does most of the work: "becomes aware, or should have become aware." That "should have" does a lot of heavy lifting in arbitration rooms.
Awareness is not the date you finally agreed the event was a claim. It is not the date your Quantity Surveyor finished the impact analysis. It is not the date you had the difficult conversation with the Employer's representative. It is the moment a competent contractor in your position should have recognized the event for what it was.
Here is how the trigger typically lands for common events:
- Unforeseen Physical Conditions — the day your crew hits the unexpected material, not the day the lab report comes back
- Weather Delay — the first day the weather event begins affecting progress, not the day the monthly report flags it
- Delayed Drawings — the day you realize the drawing's absence will disrupt the programme, not the day the float runs out
- Employer's Risk or default — the day the Employer's action (or inaction) starts impacting the Works, not the day you quantify it
- Variation impacts — the day the consequential effects appear on other work, not the day the Variation is priced
Arbitrators apply this objectively. They do not ask "did the Contractor feel aware?" They ask "would a reasonable contractor have been aware?" If a Project Manager on a similar project would have spotted the issue, the tribunal will treat you as aware — whether you acknowledged it internally or not.
The practical lesson is uncomfortable: if you think something might turn into a claim, the clock is probably already running. Pretending otherwise is how teams burn through half their 28 days before anyone even opens a draft notice.
Key Takeaway: The clock starts at awareness, judged objectively. If a reasonable contractor would have spotted the issue, you are deemed aware — even if your impact analysis has not started yet.
What Happens If You Miss It?
Under the strict language of the 1999 Red Book, missing the 28-day deadline means one thing: the Contractor loses the claim entirely. There is no partial credit, no reduced entitlement, no second chance to argue the merits. The Employer is discharged from liability, and the Engineer is not required to consider the claim.
In practice, this plays out in a few ways depending on the jurisdiction and any bespoke contract amendments:
- Straight rejection — the Engineer responds with a one-paragraph letter pointing out the late notice and closes the file. No discussion of merits.
- Conditional determination — the Engineer reviews the merits "without prejudice" but formally declines to certify anything because the time-bar applies. A polite rejection.
- Dispute Board referral — you escalate to the DAAB or arbitration, where the first question is always "when did you become aware?" If you cannot establish timely notice, the claim dies there.
There is no partial credit. You do not get proportional relief for being a few days late. Either the notice was within 28 days of awareness, or it was not. Arbitrators are not in the business of rewriting contracts because somebody's project director was on leave.
The financial impact can be brutal. I have seen contractors lose claims worth more than the annual salaries of their entire contracts team, purely because a notice was drafted on time but approved too slowly through internal review. The irony hurts: the company had the right to the money. It just had the wrong process for protecting it.
Key Takeaway: Missing the 28-day deadline usually means the claim dies. The Engineer does not have to consider merits, and arbitrators rarely rescue late notices.
Can You Challenge the Time-Bar?
Yes, in limited circumstances — but rarely, and never as your main strategy.
Different jurisdictions take different views on whether a strict 28-day time-bar is always enforceable. Courts in some civil-law jurisdictions have held that condition-precedent clauses can be softened by principles of good faith, especially where the Employer already had full knowledge of the event. Common-law jurisdictions tend to enforce the wording more strictly.
Three arguments occasionally succeed:
- Prevention principle — if the Employer's own conduct prevented the Contractor from giving timely notice, the deadline may become unenforceable. Rare and hard to prove.
- Waiver or estoppel — if the Employer or Engineer behaved as if the notice was valid (for example, processing it on the merits, requesting further information), they may be estopped from later claiming it was late.
- Ambiguity in wording — if the contract genuinely does not make clear when the clock started, the ambiguity may be read against the Employer as the party who drafted it.
But relying on any of these is like planning a road trip and assuming you will find a petrol station on the way. You might. You also might not. And the tribunal cost of arguing a time-bar dispute can easily exceed the value of the claim itself.
The pragmatic rule, learned the hard way: never design your process around the hope that a tribunal will forgive you. Design it around never needing to be forgiven.
Key Takeaway: Time-bars can occasionally be challenged through prevention, estoppel, or ambiguity — but it is expensive, uncertain, and should never be your primary strategy. Design to comply, not to litigate.
How to Track Your Deadlines
Almost every missed 28-day deadline I have investigated traced back to the same root cause: no one owned the clock. The event happened, people knew it was happening, but no single person was responsible for the notice deadline until it was too late.
A workable tracking system has four parts:
- A claims register — a single document listing every potential claim event with its awareness date, 28-day deadline, responsible owner, and current status. Updated weekly. This is non-negotiable.
- A triggering protocol — an agreed rule that any site report, instruction, or Variation flagged as potentially claim-worthy gets logged within 48 hours. Do not wait for a formal decision about whether it "really" is a claim.
- An escalation path — if the register shows a deadline within 10 days and no notice is drafted, someone above the Contracts Engineer gets automatically alerted. Not a reminder email — a real escalation.
- A notice template library — pre-approved templates for common events so drafting takes hours, not days. Variations, Extension of Time, Unforeseen Physical Conditions, Employer's Risk — have them ready on the shelf.
Some contractors still run this on spreadsheets. Others use Primavera or Aconex modules. A few use purpose-built claims management software. The tool matters less than the discipline. A boring spreadsheet with owners and deadlines, reviewed every Monday morning, beats a sophisticated system that nobody opens.
Yes, ChatNotice exists to cut the drafting time down to minutes. But that is only useful if someone actually triggered the register in the first place. Software does not save you from organizational neglect.
Key Takeaway: Own the clock. Maintain a weekly-reviewed claims register with awareness dates, deadlines, and owners. Build escalation into the process, not into hope.
The Most Common Excuses (That Don't Work)
Every time-bar dispute has a story, and the stories are depressingly similar. Arbitrators have heard them all. Here are the excuses that sound reasonable in the site office and vanish in the tribunal:
- "We were trying to mitigate first." Good for your reputation, useless for your claim. Mitigation and notification run in parallel. You do both.
- "The impact was not clear yet." Irrelevant. You notify when you become aware of the event, not when you finish calculating the damage.
- "The Engineer knew about it already." Maybe. Maybe not. Either way, actual knowledge is not a legal substitute for contractual notice under most jurisdictions.
- "We were in good-faith discussions." Discussions are not notices. A friendly meeting with the Engineer does not stop the clock.
- "The Employer was cooperative, so we did not want to be confrontational." A notice is not a hostile act. Treating it that way is how teams talk themselves out of protecting the company.
- "We were waiting for subcontractor input." Your subcontractor's schedule does not amend the FIDIC contract. Issue the notice based on what you know, update the particulars later.
- "Our contracts manager was on leave." At this point the tribunal is openly rolling its eyes.
The pattern across all of them: the Contractor had good reasons that made sense at the time, and none of them survived legal scrutiny. Reasonableness is not a defense against a condition precedent. Contracts have a way of humbling everyone equally.
Key Takeaway: None of the common excuses — mitigation, unclear impact, cooperative Employer, absent staff — overcome a missed 28-day deadline. Reasonable-sounding logic dies in arbitration.
28 Days vs 42 Days — Don't Confuse Them
One of the most common FIDIC errors — and I mean in actual issued notices, not just in training — is writing "particulars will be submitted within 28 days" when the correct wording is 42 days.
The two deadlines do different jobs:
- 28 days — the deadline for submitting the initial notice of claim under Clause 20.1. This is the one we have been discussing.
- 42 days — the deadline for submitting detailed particulars of the claim: the full case, with supporting evidence, delay analysis, and cost breakdown.
Both run from the same starting point: the date the Contractor became aware of the event. The 28-day deadline hits first; the 42-day deadline arrives exactly two weeks later. If the event has an ongoing effect, you must also submit monthly interim particulars while the impact continues, and a final detailed claim within 42 days of the effects ending.
Mixing up the two numbers in a notice is not just a typo. It signals that the Contractor does not fully understand the claims process — which is exactly the impression you do not want to give the Engineer.
A notice that promises 28-day particulars effectively tells the other side "we are going to miss the real 42-day submission by two weeks." It also hands the Engineer an easy paragraph to include in the rejection letter.
When in doubt, remember the sequence: notice at 28 days, detailed particulars at 42 days, interim updates monthly after that.
Key Takeaway: 28 days = initial notice deadline. 42 days = detailed particulars deadline. Both run from awareness. Mixing them up in a notice damages your credibility before the merits are even read.
Frequently Asked Questions
Does the 28-day rule apply under all FIDIC contracts?
Under the 1999 Red Book, Yellow Book, and Silver Book, yes — 28 days is the standard notice deadline. The 2017 2nd Edition uses a similar timeframe but introduces additional procedural steps. Always check your specific contract because Employers often modify standard FIDIC terms. If your contract has been amended, the deadlines and consequences may differ.
Are the 28 days calendar days or working days?
Calendar days. This is a common and expensive misunderstanding. Weekends, public holidays, and religious holidays all count. The clock does not pause because half the team is on leave. Plan your process around calendar time, not working time.
What if I am not sure whether an event qualifies as a claim?
Notify anyway. Sending a precautionary notice and later withdrawing it costs nothing. Failing to notify and later discovering the claim was valid costs you the claim entirely. The risk is one-sided, and the safe answer is always to send the notice.
Can a single notice cover multiple related events?
It depends. If the events share one continuous factual cause (for example, a single weather spell), a combined notice may be appropriate. If the events are independent — a Variation instruction today and an Unforeseen Physical Conditions issue next week — they need separate notices with separate awareness dates. Bundling independent events into one notice creates confusion and gives the other side a way to argue that individual events were notified late.