FIDIC Claim vs Variation: What's the Difference?
An instruction lands from the Engineer: change the pump specification, relocate a duct run, add reinforcement to a slab the geotechnical report never mentioned. Is that a Variation? Is it a Claim? Could it be both? Guessing wrong costs the Contractor a deadline, a valuation route, or both. This guide draws the line clearly, so the site team sends the right document on the right day.
What Is a Variation Under FIDIC?
A Variation, under Sub-Clause 13.1 of the FIDIC 1999 Red Book, is a change to the Works instructed by the Engineer. It can add work, omit work, or change how, when, or in what sequence work is done. The Employer's side initiates it — the Engineer issues the instruction, and the Contractor carries it out.
Once instructed, a Variation runs on its own track. The Contract Price is adjusted using Clause 12 — Bill of Quantities rates where they apply, fair new rates where they do not — and the Time for Completion is adjusted where the change genuinely affects it. Nobody has to prove entitlement to be paid for a Variation; the entitlement is built into being instructed to do the extra or different work.
For the full mechanics — instructed vs constructive Variations, the two notice paths, how valuation disputes actually play out — see the dedicated Clause 13.1 guide. This article is about telling a Variation apart from a Claim in the moment, not the deep mechanics of either.
Key Takeaway: A Variation is a change to the Works instructed by the Engineer under Sub-Clause 13.1. The Employer's side starts it. Price and time are adjusted through Clause 12 valuation, not through proving fault or loss.
What Is a Claim Under FIDIC?
A Claim is different in one basic way: the Contractor starts it, not the Engineer. A Claim asserts entitlement to time, cost, or both, arising from an event that is not itself an instruction to change the Works — adverse weather (Sub-Clause 8.4(c)), unforeseen physical conditions (Sub-Clause 4.12), late access to the Site (Sub-Clause 2.1), delayed drawings or instructions (Sub-Clause 1.9), delays caused by authorities (Sub-Clause 8.5), or an Employer's risk event (Sub-Clause 17.3).
Every one of those runs through the Sub-Clause 20.1 procedure: notice within 28 days of the Contractor becoming aware of the event, followed by detailed particulars. Nobody instructed the weather to be exceptionally adverse, and nobody instructed the ground conditions to be different from the tender data. The Contractor has to establish that the event happened, that it was outside its control or risk, and what it caused.
That is the real dividing line. A Variation is something the Employer's side asked for. A Claim is something that happened to the Contractor that it now has to prove.
Key Takeaway: A Claim asserts entitlement arising from an event the Contractor did not cause and was not instructed to do — weather, ground conditions, late access, late drawings, authority delays, Employer's risks. The Contractor initiates it and has to prove it.
The Core Distinction: Who Moves First
One quick test settles most cases: did the Engineer tell the Contractor to do something different, or did something happen to the Contractor that it now needs compensating for?
- It is a Variation when — the Engineer instructs a change to scope, sequence, or method; the instruction exists whether or not it is ever labelled "Variation"; the Contractor's job is to carry out the instruction and get it valued.
- It is a Claim when — an event outside the Contractor's control happens (weather, ground conditions, access, drawings, authorities, Employer default); nobody instructed it; the Contractor's job is to notify it and prove the effect.
The test is simple to state and genuinely difficult to apply on a live Site, because the Engineer's instructions do not arrive with a stamp that says "this is a Variation." Some do; a formal Variation Instruction under Sub-Clause 13.1 is unmistakable. Many more arrive as a comment in a site meeting, a mark-up on a drawing, or a verbal direction that changes the method without anyone calling it anything at all.
Key Takeaway: Ask who moved first. An instruction from the Engineer's side points to a Variation. An event that happened to the Contractor points to a Claim. The label the Engineer gives it matters less than what actually occurred.
Why the Distinction Changes the Deadline
Getting the characterisation wrong is not just a paperwork problem — it changes which date starts the clock.
For a Variation, the notice clock runs from the date of the instruction, not from when the Contractor first feels the effect. For every other Claim type — weather, unforeseen conditions, access, drawings, delays by authorities, Employer's risks — the clock runs from awareness of the event. Awareness before an instruction is legally inert for a Variation; it is everything for a Claim.
This trips people up in a specific, recurring way. An instruction is given on day one, but its consequential impact on the programme only becomes obvious three weeks later, once the knock-on sequencing problem shows up. The direct valuation of the instructed work is fine — Clause 13 has its own timetable driven by the Engineer's request. But if there is a separate Sub-Clause 20.1 notice needed for the consequential delay or disruption, treating "day one" as the only relevant date, or waiting because "it's already a Variation," can leave that consequential notice late.
Key Takeaway: A Variation's notice clock runs from the instruction date. Every other Claim type runs from awareness of the event. When a Variation causes a separate consequential impact, that impact has its own awareness date — do not assume the instruction date covers it.
Why the Distinction Changes What You Recover
The characterisation also decides what the Contractor is entitled to, because different clauses give different remedies:
- Variation (Sub-Clause 13) — valued under Clause 12; price adjustment normally includes reasonable profit, and time is adjusted where the change genuinely affects the programme.
- Weather Delay (Sub-Clause 8.4(c)) — time only, no cost.
- Unforeseen Physical Conditions (Sub-Clause 4.12) — time and Cost, but no profit.
- Access to Site (Sub-Clause 2.1) and Delayed Drawings (Sub-Clause 1.9) — time, Cost, and reasonable profit.
- Delays by Authorities (Sub-Clause 8.5) — time only.
Mislabel a genuine Variation as a generic delay claim and the Contractor risks losing the profit margin it was actually entitled to. Mislabel a weather event as something else entirely and the Engineer has grounds to reject the whole submission on the wrong clause alone. The characterisation is not academic — it is the difference between the notice landing on the Engineer's desk as something they recognise and can act on, or as something they can send back for clarification while the clock keeps running.
Key Takeaway: Each clause gives a different remedy — a Variation typically includes profit, weather and authority delays give time only, and unforeseen conditions give time and Cost without profit. Citing the wrong clause risks the wrong remedy, or a rejected submission.
The Grey Zone: When the Instruction Isn't Labelled Anything
The hardest cases are the ones where nobody has said the word "Variation" or the word "Claim" — the Engineer has simply changed something informally, and the Site is left to work out what just happened. This is the constructive Variation problem, covered in depth in the Clause 13.1 guide, but it deserves a mention here because it is exactly where the claim-vs-variation confusion starts.
A redesign suggestion in a coordination meeting, a rejection that forces a different construction method, an unofficial "just do it this way" from site staff — none of these come with a formal instruction, yet all of them can change the Works enough to qualify as a Variation. Waiting for the Engineer to formally call it one before reacting is how the notice clock quietly runs out.
The safest response when the characterisation is genuinely unclear is not to guess. It is to notify both ways at once, and let the Engineer's response settle the question.
Key Takeaway: An unlabelled instruction can still be a Variation. Waiting for formal confirmation before notifying is a common way the deadline is missed. When the characterisation is unclear, notify — do not wait to decide first.
Template: Reserving Both Routes When You're Not Sure Yet
Once the characterisation is settled, use the dedicated templates — the Variation Order template for a confirmed Variation, or the Notice of Claim template for a confirmed event-based Claim. But while it is still unclear which one applies, this shorter dual-reservation letter keeps both doors open without committing to either label prematurely.
This is deliberately not the primary document — it is a placeholder that stops a genuine entitlement from being time-barred while the characterisation gets sorted out with the Engineer. Once the answer comes back, the Contractor follows up promptly with the correct, single-purpose notice. Describing the situation in plain language to ChatNotice works for either outcome — it drafts a Variation Claim notice under Sub-Clause 13.1/20.1 or a generic Sub-Clause 20.1 claim notice once the facts are known, with the right clause already in place.
Key Takeaway: When the characterisation is genuinely unclear, send a dual-reservation notice rather than waiting. It protects both the Variation and Claim routes while the Engineer confirms which one applies — then switch to the single-purpose template.
Worked Example
During a coordination meeting, the Resident Engineer tells the Contractor's site team to reroute a section of buried drainage around a newly discovered utility line — verbally, with no written instruction issued. The Contractor is not sure whether this will be formalised as a Variation or whether it should be treated as an unforeseen condition. It sends the dual-reservation notice the same week.
Two weeks later, the Engineer confirms in writing that the reroute is being treated as a Variation, since the utility relocation itself was a discrete, instructable change rather than a condition the Contractor is claiming against. The Contractor then follows up with a standard Variation Order confirmation, and the earlier dual-reservation notice has already protected the entitlement in the meantime.
Key Takeaway: The worked example shows the pattern: notify both routes promptly when unclear, get the Engineer's confirmation, then switch to the single, correct template. The Contractor never had to guess right the first time — it just had to notify on time.
Common Mistakes
- Assuming a verbal direction doesn't count. An instruction given in a meeting or on a phone call can still start the Variation clock — get it confirmed in writing promptly.
- Waiting for the word "Variation" before acting. If the Engineer never uses the label, waiting for it can run the Claim-route deadline out while the Variation conversation is still unresolved.
- Treating the Variation valuation as covering everything. The direct Clause 12 valuation does not automatically capture consequential delay or disruption — that usually needs a separate Sub-Clause 20.1 notice.
- Citing the wrong clause. A weather-caused delay notified as a generic claim, or a genuine Variation notified only as a Claim, risks the wrong remedy or a submission the Engineer sends back for clarification.
- Confusing the two clock triggers. Instruction date for Variations, awareness date for everything else. Mixing them up is one of the most common ways a valid entitlement is time-barred.
Key Takeaway: Most mistakes come from waiting — waiting for a formal label, waiting to see if the valuation covers everything, waiting to decide the clause. Notify promptly on the correct trigger date and let the Engineer's response settle the rest.
Frequently Asked Questions
Can something be both a Variation and a Claim at the same time?
Yes. A Variation instruction covers the direct value of the changed work under Clause 13. A separate Clause 20.1 notice may still be needed for consequential effects — disruption, delay to other activities, acceleration — that the direct valuation does not capture. The two are not mutually exclusive, and skipping the second notice because the first one already exists is a common way Contractors leave money behind.
What if the Engineer's instruction never uses the word Variation?
It can still be one. A Variation is defined under FIDIC Sub-Clause 13.1 by its effect on the Works, not by the label the Engineer gives it. An instruction that changes scope, sequence, or method given verbally in a site meeting, or buried in an email about something else, can still start the Variation clock. This is the constructive Variation trap, and it is the Contractor's job to recognise it in real time.
Does the 28-day notice deadline apply to Variations?
The deadline still exists, but the trigger date is different. For a Variation, the clock runs from the date of the instruction. For every other claim type under FIDIC 1999 — weather, unforeseen physical conditions, late access, delayed drawings, delays by authorities, Employer's risks — the clock runs from when the Contractor became aware, or should have become aware, of the event. Confusing the two starting points is a common way a valid entitlement is time-barred.
If I am not sure whether something is a Variation or a Claim, what should I do?
Send a notice that reserves both routes rather than waiting to decide. A short letter that references the instruction, asks the Engineer to confirm whether it is being treated as a Variation, and separately reserves the Contractor's rights under Sub-Clause 20.1 keeps both doors open. Waiting to characterise the event correctly before notifying anything is one of the most common ways a genuine entitlement is lost.
Who decides whether something is a Variation or a Claim?
In the first instance, the Engineer, when it makes its determination under Sub-Clause 3.5. If the Contractor and Engineer disagree on the characterisation, either party may refer the dispute to the Dispute Adjudication Board under Sub-Clause 20.4.
Authoritative Sources
This guide reflects the FIDIC Conditions of Contract and established construction-law authority. For the primary materials, see:
- FIDIC Conditions of Contract — the official contract suite published by the International Federation of Consulting Engineers, which sets out both the Sub-Clause 13 Variation procedure and the Sub-Clause 20.1 claims procedure.
- Obrascon Huarte Lain SA v HM Attorney General for Gibraltar — the leading authority on the validity and timing of a notice of claim under Clause 20.1, relevant to how strictly the awareness-date trigger is applied.
About the Author
Muhammad M. Jiwani is a Project Director with 15 years' experience on major infrastructure and energy projects administered under FIDIC contracts. He writes from first-hand experience serving notices and managing contractual claims on live projects.