How to Notify a Variation Under FIDIC (Red & Yellow Book): The Notice Mechanics That Protect Your Entitlement

Most contractors think a variation is protected the moment the Engineer tells them to do something different. It is not. Under the FIDIC Red and Yellow Books the value of a variation is decided by a chain of formal steps, and every link in that chain is a place where entitlement leaks away. An oral instruction that is never confirmed, a change that is treated as a claim, a valuation that is never agreed - each of these quietly converts extra work into free work. The mechanics are not difficult, but they are unforgiving, and they reward the contractor who understands the process rather than the one who simply does the work.

What Clause 13 Actually Governs

Variations under FIDIC are governed by Clause 13. In both the 1999 and 2017 editions of the Red and Yellow Books, Clause 13 gives the Engineer the power to instruct changes to the Works and sets out how those changes are initiated, agreed or instructed, and valued. A variation can be an alteration to the quantity, quality or character of the Works, a change in levels or dimensions, the removal or addition of work, or a change to the sequence or timing of construction. The essential point is that a variation is a change the Engineer is contractually entitled to instruct, and which the contract already provides a route to value and pay for.

This is why a variation is not the same thing as a claim. A variation flows through Clause 13 and is valued under the valuation rules of the contract. A claim for additional time or money flows through the claims machinery - Clause 20.1 in the 1999 forms and the Clause 20.2 sub-clauses in 2017 - and carries a strict notice deadline with a time-bar consequence. Confusing the two is one of the most common and expensive mistakes on site, and it is worth being precise about which mechanism you are in. We set out the wider distinction in Change Order vs Variation vs Compensation Event, and it matters here because the notice you give depends entirely on which route the event travels.

The Variation Instruction Versus the Claim Notice

There are two quite different pieces of paper at work on a FIDIC job, and contractors routinely conflate them. The first is the variation instruction: the Engineer's direction, under Clause 13, to change the Works. When the Engineer issues a clear written instruction to vary the scope, the entitlement to be paid for that change is established by the instruction itself. The work is authorised, it will be measured or valued under the contract, and it will find its way into the payment cycle. In that situation the contractor's job is to record, price and submit - not to serve a claim notice.

The second piece of paper is the claim notice, and it becomes necessary when the change does not arrive as a clean written instruction. If the variation causes delay or cost that the valuation rules do not fully capture, or if there is a dispute about whether an instruction is a variation at all, the contractor must protect the additional time or money through the claims regime and its 28-day notice. This is the trap: a contractor who receives a genuine variation but suffers knock-on delay may be fully protected on the value of the varied work and completely unprotected on the prolongation it caused, simply because it relied on the variation instruction and never served the separate claim notice. Missing that deadline is fatal, for reasons we explain in The 28-Day Rule That Kills More Claims Than Any Dispute.

Written Versus Oral Instructions - and How to Convert One Into the Other

In principle a variation should be instructed in writing. In practice, on a fast-moving site, instructions are given verbally by the Engineer or the Engineer's Representative all the time - across a table at a progress meeting, over the radio, in a corridor. The work gets done. The paper never appears. Months later, when the account is settled, the Engineer has no record of instructing anything, and the contractor is left holding cost it cannot prove was authorised.

FIDIC anticipates this. The forms contain a mechanism that allows an oral instruction to be confirmed in writing by the contractor, so that if the Engineer does not respond within a defined period, the instruction stands as confirmed. The practical discipline is simple and it should be automatic: whenever you receive an oral instruction that changes the Works, send a written confirmation the same day. State that on a given date the Engineer instructed a described change, that you are treating it as a variation instruction under Clause 13, and that unless the Engineer objects within the contractual period you will proceed on that basis. This single habit converts a fragile verbal exchange into a documented instruction, and it shifts the burden onto the Engineer to correct the record rather than onto you to reconstruct it.

The confirmation must be accurate and neutral. It is not the place to inflate scope or editorialise. Describe what was actually instructed, when, and by whom, and let the record speak. A confirmation that overstates the instruction invites a rejection that undermines your credibility on everything else.

Deemed and Constructive Variations

Not every variation announces itself. A deemed or constructive variation arises where the contractor is effectively required to do something outside the original scope even though no one issued a document headed variation. The Engineer rejects conforming work and demands a higher standard. A drawing revision quietly adds work the specification did not contain. An instruction to accelerate or resequence changes the character of the work. In each case the substance is a variation even though the label is missing.

The danger with deemed variations is that, because no instruction was issued, the contractor often does the work without triggering any of the protective machinery. The correct response is to notify. Put the Engineer on notice, promptly and in writing, that you consider the direction or circumstance to constitute a variation, and ask for a formal instruction under Clause 13. If the Engineer disputes that it is a variation, you are now in a claim, and the claim notice deadline is running - so the same notice should be framed to protect your position under the claims regime as well. The guiding principle is that ambiguity is not a reason to stay silent. Ambiguity is the reason to notify.

The Cost of Getting Notice Wrong on a Live Project

The commercial consequences of poor variation notice are concrete and they compound. Consider a subcontractor on a QAR 60 million package who absorbs a stream of small verbal instructions over a six-month period - a revised detail here, an extra run of services there - none of them confirmed in writing. Individually each feels too minor to formalise. Collectively they might represent QAR 3 to 4 million of unrecovered work by the time the final account is negotiated, and with no contemporaneous record the contractor has almost no leverage to recover it. The work was real. The proof was never created.

The second cost is the knock-on time and money that a variation causes but that the valuation of the varied work alone does not capture. A properly valued variation pays for the varied work; it does not automatically pay for the disruption to unchanged work or the prolongation of the programme. Those consequences must be captured and notified separately and contemporaneously, which is why the discipline of recording variations as they happen matters so much - a theme we develop in Preventing Disputes Over Variation Valuation Before They Start. The contractor who builds this discipline into its routine, rather than leaving it to the final account, is the one who gets paid. Building that routine, and owning it independently of the delivery team, is precisely what CALIM's prevention services exist to provide.

A Practical Notice Routine

The routine that protects variation entitlement on a FIDIC job is not complicated, and its power is in its consistency. Confirm every oral instruction in writing the same day. Ask for a formal Clause 13 instruction whenever a direction looks like a variation but is not labelled as one. Keep a variation register that logs the date, the source, the description and the status of every change. Record the time and cost consequences of each variation as they arise, not months later. And where a variation causes delay or cost beyond the value of the varied work itself, serve the separate claim notice inside the contractual deadline. Done together, these steps mean that when the account is finally settled the paperwork already exists, the entitlement is already documented, and the negotiation is about value rather than about whether the work was authorised at all.

Frequently Asked Questions

Do I need to serve a claim notice for every variation on a FIDIC job?

No, not for the value of the varied work itself. When the Engineer issues a clear written variation instruction under Clause 13, the entitlement to be paid for that work is established by the instruction, and it is valued through the contract's valuation rules without a separate claim notice. You do need to serve a claim notice, within the contractual deadline, where the variation causes additional time or cost that the valuation of the varied work does not capture, such as prolongation or disruption to unchanged work. The safe discipline is to treat those knock-on consequences as a separate, notifiable entitlement.

The Engineer gave me a verbal instruction. Is it valid?

A verbal instruction can change the Works, but on its own it is very hard to prove later. FIDIC provides a mechanism for the contractor to confirm an oral instruction in writing, so that if the Engineer does not object within the contractual period the instruction stands as confirmed. The practical rule is to confirm every oral instruction in writing the same day, describing accurately what was instructed, when, and by whom, and stating that you are treating it as a variation under Clause 13. That confirmation converts a fragile verbal exchange into a documented instruction and shifts the burden of correction onto the Engineer.

What is a deemed or constructive variation?

A deemed or constructive variation is a change to the substance of the work that occurs without a formal instruction headed variation. Examples include the Engineer rejecting conforming work and demanding a higher standard, a drawing revision that adds work the specification did not contain, or a direction to accelerate or resequence. Because no instruction was issued, the protective machinery is easy to miss. The correct response is to notify the Engineer promptly in writing that you consider the direction a variation and to request a formal Clause 13 instruction, while also protecting your position under the claims regime in case the Engineer disputes that it is a variation.

What is the difference between a variation instruction and a claim under FIDIC?

A variation instruction is the Engineer's direction under Clause 13 to change the Works, and it establishes the entitlement to be paid for that change through the contract's valuation rules. A claim is a request for additional time or money that runs through the claims machinery - Clause 20.1 in the 1999 forms and the Clause 20.2 sub-clauses in 2017 - and carries a strict notice deadline with a time-bar consequence. The two are not interchangeable. Relying on a variation instruction alone can leave the knock-on delay and disruption unprotected, because those are recovered through the claims route, not the valuation of the varied work.

How long do I have to notify a variation-related claim?

Under the FIDIC claims regime the Notice of Claim must generally be given within 28 days of the date the contractor became aware, or should have become aware, of the event or circumstance. That period runs from awareness of the event, not from when you decide to formalise the claim, which is why the clock can expire while a variation is still being absorbed informally on site. Because a properly drafted notice provision operates as a condition precedent, a late notice can extinguish an otherwise valid entitlement, so record the date of awareness for every potential claim and notify inside the deadline.

On a FIDIC job the variation is not protected by the work you did - it is protected by the notice you sent, so make the notice automatic and the entitlement takes care of itself.

Note: This article provides general information on FIDIC variation and notice mechanics and is not legal advice. The exact operation of Clause 13, the confirmation of oral instructions, and the claims regime depends on the specific edition, the Particular Conditions, and the governing law, which vary between projects and jurisdictions. Contractors should obtain advice tailored to their particular contract before relying on any notice or variation position.