How Should Variation Claims Be Documented Under a FIDIC Contract? The Instruction Proves the Change, Not the Payment

Authored by R & D Law Chambers LLP Ravish Bhatt  |  Advocate, Bar Council of Gujarat (G/504/2008)  |  Dual-qualified lawyer (India and England & Wales)  |  ADIT, CIOT, London  |  SRA (non-practising) Registration No. 492 477 Published: 29 September 2026  |  Last reviewed: 29 September 2026

 

This article refers to the 1999 and 2017 editions of the FIDIC Red, Yellow and Silver Books, and to the Arbitration and Conciliation Act, 1996 and the Indian Contract Act, 1872 as at 29 September 2026. It describes the decision of the Judicial Committee of the Privy Council in Uniform Building Contractors Ltd v The Water and Sewerage Authority of Trinidad and Tobago, [2026] UKPC 2, decided on 22 January 2026 on appeal from Trinidad and Tobago, as a factual account of how that court read the FIDIC conditions. We advise on Indian law only, for businesses anywhere, wherever a matter has an India connection. Foreign law is described factually with attribution, never analysed as advice.

 

Short answer. A FIDIC variation claim turns on two questions that only documents made at the time can answer: was the work outside what the contract price already bought, and did the contractor take the procedural steps that turn an instruction into an entitlement to be paid? In January 2026 the Privy Council dismissed a contractor’s variation claim on both grounds, in a record it described as almost entirely lacking contemporaneous documents.

 

Index of Topics

1. Why the Engineer’s View Does Not Make Work a Variation
2. How a Variation Is Initiated Under the 1999 and 2017 Forms
3. Recording an Oral Instruction Before It Becomes a Dispute
4. Instruction, Determination, Entitlement: Why the Middle Step Decides Payment
5. When the Engineer Does Not Act: The Notice of Claim
6. The Engineer Cannot Waive the Procedure
7. The Records That Prove Cost and Time
8. Why a Formula Does Not Replace the Records in an Indian Arbitration
9. A Variation Register That Survives a Dispute
10. Frequently Asked Questions
11. How R & D Law Chambers Works on These Matters

1. Why the Engineer’s View Does Not Make Work a Variation

Short answer. Because a Variation is defined by the contract, not by the Engineer. In the Privy Council’s January 2026 decision, the Engineer gave evidence that four items were variations, and the Board held that none was, because the lump sum already included each of them. The first record a variation claim needs is therefore the contract baseline, not the instruction.

 

In Uniform Building Contractors Ltd v The Water and Sewerage Authority of Trinidad and Tobago, [2026] UKPC 2, a contractor under a FIDIC Yellow Book (1999) design-build contract claimed payment for four items of work: laying pipe in the roadway rather than the verge, removing unsuitable excavated material, importing backfill, and night work. The Engineer gave evidence for the contractor that he regarded all four as variations. The Court of Appeal of Trinidad and Tobago accepted that evidence. The Privy Council reversed it.

The Board held that whether work is a variation is primarily a function of the contract terms, and that the Engineer’s view cannot displace their proper application (paragraphs 15 and 29). A Variation was defined in Sub-Clause 1.1.6.9 as a change to the Employer’s Requirements or the Works instructed or approved as a Variation under Clause 13. The contract was a lump sum: Sub-Clause 4.11 deemed the contractor to have satisfied itself of the sufficiency of the Accepted Contract Amount, and the specifications and bill of quantities expressly covered each of the four items. The Particular Conditions reinforced that allocation: sub-clause 1.1.6.13 made the contractor responsible for both preliminary and final design, sub-clause 4.10 deemed it to have satisfied itself on site data, sub-clause 5.1 made it responsible for the design of the Works, and preamble P4 to the Bill of Quantities declared the contract a lump sum fixed price not subject to variation (paragraphs 20 and 22). The roadway item failed for a further reason: moving the pipe from verge to roadway was a change between the contractor’s own preliminary and final designs, both its responsibility, so it could not be a Clause 13 variation (paragraph 34). None was a variation (paragraphs 30 to 50).

The lesson for documentation is sequence. Before recording what changed, the contractor needs a record of what the price bought: the specification clause, the drawing revision, the bill item or the Employer’s Requirements paragraph that the instruction departs from. A variation file that begins with the instruction and not with the baseline answers the second question before the first.

2. How a Variation Is Initiated Under the 1999 and 2017 Forms

Short answer. Under the 1999 forms, and under the 2017 Red and Yellow Books, the Engineer initiates a Variation either by instruction or by requesting a proposal. The 2017 Silver Book places that function with the Employer. Under the 2017 forms an instruction is given by a Notice describing the change and stating any requirements for recording Costs, and the Contractor submits detailed particulars within 28 days, or within another agreed period. The time and price adjustment is then agreed or determined under Sub-Clause 3.7, or Sub-Clause 3.5 of the Silver Book.

 

Under the 1999 forms, Sub-Clause 13.1 allows the Engineer to initiate Variations before the Taking-Over Certificate by an instruction or by a request for a proposal. Sub-Clause 13.3 requires each instruction to execute a Variation, with any requirements for the recording of Costs, to be issued to the Contractor, who acknowledges receipt, and requires the Engineer, on instructing or approving a Variation, to agree or determine the adjustment to the Contract Price under Sub-Clause 3.5, including reasonable profit. The Privy Council set these provisions out at paragraph 51.

The 2017 forms separate the two routes. Under Sub-Clause 13.3.1, Variation by Instruction, the Engineer gives a Notice describing the required change and stating any requirements for recording Costs. The Contractor proceeds with the work and, within 28 days of receiving the Notice, or within another period the Contractor proposes and the Engineer agrees, submits detailed particulars, including a proposal for modifying the programme and a proposal for adjusting the Contract Price with supporting particulars. The Engineer then proceeds under Sub-Clause 3.7 to agree or determine any extension of time and the adjustment to the Contract Price. Sub-Clause 13.3.2 provides the alternative of a Variation by Request for Proposal. Under the 2017 Silver Book the Employer gives the instruction, under Sub-Clause 3.4, and agreement or determination is under Sub-Clause 3.5.

The instruction therefore carries two pieces of information that the contractor’s records must follow: the description of the change, which fixes the scope being valued, and the Engineer’s requirements for recording Costs, which fix the form in which the cost evidence must be kept.

3. Recording an Oral Instruction Before It Becomes a Dispute

Short answer. Confirm it in writing at once. The Privy Council declined to hold that an oral instruction is automatically invalid, but noted that the usual protection is a Confirmation of Verbal Instruction sent by the contractor to the Engineer, which gives the Engineer the chance to raise any issue at the time rather than years later.

 

Clause 3.3 of the 1999 conditions in the Privy Council case required instructions in writing. The Board said it would not hold that an oral instruction was automatically invalid for that reason alone, since a breach of the written-instruction requirement could be waived by both parties. It then observed that such debates are increasingly rare because contractors can record oral instructions in writing, most commonly by a Confirmation of Verbal Instruction sent to the Engineer (paragraph 54).

A useful confirmation records the date, the person giving the instruction and his authority, the exact words used, the drawing or specification reference affected, the reason given, and a statement that the contractor treats the instruction as a Variation. It should be sent before the work starts, or as close to that as the site allows, so that the Engineer’s response or silence is itself part of the record.

On the facts, however, the absence of a written instruction was immaterial. What decided the case were the steps the contractor never took afterwards (paragraph 55).

4. Instruction, Determination, Entitlement: Why the Middle Step Decides Payment

Short answer. Because, as the Privy Council read the 1999 conditions, the contractor’s entitlement to be paid for a variation arises from the Engineer’s agreement or determination of its value, not from the instruction. A contractor who never submits a valuation and never asks for a determination has, on that reading, nothing to be paid under the contract.

 

The Board held that, even assuming the Engineer had orally instructed the work, the next step was for the contractor to notify the additional cost and to seek a determination under Sub-Clause 3.5 of the value of the extra work, supported by a proper proposal. The contractor’s contractual entitlement was to the amount the Engineer determined. With no notice, no request for a determination and no material on which one could be made, there was no entitlement (paragraphs 55, 56 and 59).

Under the 2017 Red and Yellow Book forms the same middle step appears as the Sub-Clause 3.7 agreement or determination that follows the contractor’s detailed particulars under Sub-Clause 13.3.1; in the 2017 Silver Book it is the Sub-Clause 3.5 agreement or determination. The 2022 reprint of the 2017 Red Book lists Sub-Clause 13.3.1 among the “matters” the Engineer agrees or determines under Sub-Clause 3.7, as distinct from Claims under Clause 20. That distinction matters to documentation because a matter and a Claim run on different notices and different clocks.

The documents that prove the middle step are the contractor’s own: the submission of particulars within the 28 days, the programme proposal, the price proposal with its build-up, and the covering letter asking the Engineer to proceed to agreement or determination. Each should cite the Sub-Clause under which it is given.

5. When the Engineer Does Not Act: The Notice of Claim

Short answer. Where the Engineer does not act, the Privy Council treated a Clause 20 claim as the contractor’s route under the 1999 conditions. The 2017 forms require a Notice of Claim within 28 days of awareness and a fully detailed Claim within 84 days; the 1999 forms allow 28 and 42 days.

 

The Privy Council described Sub-Clause 20.1 of the 1999 conditions as the route to unlock the problem where the Engineer has not engaged at the Clause 13 or Sub-Clause 3.5 stage, and held that the contractor’s failure to use it was fatal (paragraphs 58 and 60). It held Sub-Clause 20.1 to be a condition precedent: if the contractor does not give notice within 28 days, it is not entitled to additional payment and the Employer is discharged (paragraph 61). It added that termination of the contract did not revive claims already time-barred (paragraphs 67 and 68).

The 2017 forms keep the 28-day Notice of Claim in Sub-Clause 20.2.1 and extend the period for the fully detailed Claim from 42 to 84 days in Sub-Clause 20.2.4. The fully detailed Claim must include a description of the event, a statement of the contractual or other legal basis of the Claim, the contemporary records relied on, and detailed supporting particulars of the time and money sought. If the statement of the legal basis is not given within the 84 days, the Notice of Claim is deemed to lapse, subject to the Engineer’s own notice within 14 days. Under Sub-Clause 20.2.2 the Engineer must give notice within 14 days if it considers a Notice of Claim out of time; if it does not, the Notice is deemed valid.

Whether an Indian court or tribunal applies a FIDIC notice time bar in the same way is a separate question of Indian law. Section 28 of the Indian Contract Act, 1872 makes void, to that extent, an agreement which extinguishes a party’s rights or discharges a party from liability on the expiry of a specified period so as to restrict the enforcement of rights. This article does not address how that provision applies to a FIDIC notice clause. The documentation point does not depend on the answer: a Notice of Claim given in time removes the question. Who bears the cost of a change in law, which reaches the contractor through the same claims route, is a separate subject.

6. The Engineer Cannot Waive the Procedure

Short answer. The Privy Council held that the Engineer, who under Sub-Clause 3.1 has no authority to amend the contract or to relieve either party of its obligations, could not waive the notice and determination requirements. Waiver or estoppel had to come from the Employer, be pleaded, and be proved by evidence of representation, reliance and detriment.

 

The Court of Appeal had found that the Engineer waived the written-notice and time requirements because the project was run flexibly on site. The Board held that finding contradictory: the Engineer had no authority to amend the contract, and a waiver of its procedural terms would have been exactly that (paragraphs 15, 76 to 83). Only a party to the contract could waive or amend it, and there was no evidence that anyone with the Employer’s authority had done so (paragraphs 84 to 87).

The Board also held that waiver and estoppel had not been pleaded or supported by evidence at trial and could not be raised for the first time on appeal, drawing on the approach in MWB Business Exchange Centres Ltd v Rock Advertising Ltd [2018] UKSC 24 (paragraphs 71 to 75). It distinguished its own decision in Gordon Winter Co Ltd v NH International (Caribbean) Ltd [2025] UKPC 52 as a case in which both parties had agreed on the evidence not to follow the FIDIC procedure (paragraph 65).

For documentation, the point is who is on the correspondence. Assurances from the Engineer that “payment will be sorted out later” protect nothing. Where a contractor proceeds on such an assurance, the record that matters is a letter to the Employer itself, and the Employer’s reply.

7. The Records That Prove Cost and Time

Short answer. Contemporary records made when the work is done, in the form the Engineer’s instruction requires: labour, plant and material allocation to the variation, quantities measured against the baseline, subcontractor instructions and invoices, and programme updates showing the affected activities. Under Sub-Clause 20.2.3 of the 2017 forms, the Engineer’s monitoring of those records does not imply acceptance of their accuracy.

 

The 2017 forms require the claiming party to keep contemporary records necessary to substantiate a Claim, and allow the Engineer to monitor them and to instruct further records. Sub-Clause 20.2.3 makes clear that monitoring, inspection or an instruction to keep records does not imply acceptance of the records’ accuracy or completeness. A contractor cannot rely on the Engineer’s having seen its daily sheets as proof that they are right.

Four categories of record do most of the work. Quantity records measure what was done against what the baseline required, with the measurement method stated. Resource records allocate labour, plant and materials to the varied work separately from base-scope work on the same day. Cost records trace the price proposal to invoices, subcontract orders and rates in the contract. Programme records show the activity affected, when it was affected, and the effect on the critical path, updated when the variation is instructed and again when it is complete.

The Privy Council’s account of the record in its case is instructive: the only claim letters sent during the works concerned price increases from aggregate suppliers, which under a lump sum contract had no contractual basis at all, and later invoices produced in 2010 added nothing (paragraph 46). The Board drew a second point from the same record: the documents that did exist did not support the suggestion that the contractor itself saw the items as legitimate variations, and on any fair reading the claim was unclear and tentative (paragraphs 46 and 49). Contemporaneous records therefore do two jobs. They prove cost and time, and they show how the contractor characterised the work when it was done.

8. Why a Formula Does Not Replace the Records in an Indian Arbitration

Short answer. Because Indian courts require evidence of the loss. In Unibros v All India Radio, decided on 19 October 2023, the Supreme Court upheld the setting aside of an award of loss of profit for delay computed on Hudson’s formula, because evidence substantiating the loss was missing. A formula calculates a proved loss; it does not prove it.

 

In Unibros v All India Radio, 2023 INSC 931, the contractor on a Delhi construction project was awarded loss of profit for a prolonged contract period, calculated by Hudson’s formula. A single judge of the Delhi High Court set that part of the award aside under section 34 of the Arbitration and Conciliation Act, 1996, a Division Bench dismissed the appeal under section 37, and the Supreme Court dismissed the further appeal. The Court held that the evidence needed to substantiate the claimed loss of profitability was absent, and that without it the award could not stand.

The case concerned delay damages rather than the valuation of a variation, but the documentary point carries across. A variation claim priced on a percentage uplift, a notional productivity loss or an unexplained rate, with nothing on the record to show that the cost was actually incurred because of the varied work, invites the same objection. The records described in section 7 are what make the pricing evidence rather than assertion.

For time, the equivalent discipline is a programme analysis that uses the contractor’s own contemporaneous updates. A retrospective programme built for the arbitration, with no contemporaneous programme to test it against, is open to the objection that nothing made at the time supports it.

9. A Variation Register That Survives a Dispute

Short answer. One register, updated weekly, that links each variation to its baseline, instruction, notices, submissions, determination and cost evidence, with dates. Its value is not administrative. It is the document that lets a tribunal, years later, see that each procedural step was taken in time and that the cost claimed can be traced to the work.

 

Register field	What it proves	Link to the contract
Baseline reference	That the work was outside what the price bought	Definition of Variation; Sub-Clause 4.11 (1999)
Instruction or confirmation, with date and author	That the change was instructed by someone with contractual authority	Sub-Clauses 3.3, 13.1 and 13.3 (1999 Red and Yellow); 3.5 and 13.3.1 (2017 Red and Yellow); 3.4 and 13.3.1 (2017 Silver)
Particulars submitted, with date	That the valuation step was taken within 28 days	Sub-Clause 13.3.1 (2017)
Request for agreement or determination	That the middle step was invoked	Sub-Clause 3.5 (1999 Red and Yellow); 3.7 (2017 Red and Yellow); 3.5 (2017 Silver)
Notice of Claim, with date	That the claims route was preserved if the Engineer did not act	Sub-Clause 20.1 (1999) or 20.2.1 (2017)
Fully detailed Claim, with date	That the claim was particularised in time	Sub-Clause 20.2.4 (2017)
Cost and resource records	That the cost was incurred because of the varied work	Sub-Clause 20.2.3 (2017)
Programme update reference	That time was affected, and when	Sub-Clauses 8.3 and 13.3.1
Determination or response, with date	Where the entitlement now stands	Sub-Clause 3.5 (1999 Red and Yellow); 3.7 (2017 Red and Yellow); 3.5 (2017 Silver)

 

Three disciplines keep the register honest. It is kept by someone who is not pricing the claim. Each entry cites the document itself, not a summary of it. And entries are never back-dated: a late entry marked as late is evidence of candour; a back-dated one destroys the credibility of every other line.

10. Frequently Asked Questions

Does an Engineer’s instruction automatically make work a variation under FIDIC?

No. A Variation is what the contract defines it to be. In Uniform Building Contractors v WASA, [2026] UKPC 2, the Privy Council held that four items the Engineer regarded as variations were not, because the lump sum already covered them under Sub-Clause 4.11 and the specifications. The Engineer’s view was relevant at most, and could not displace the contract terms.

How long does a contractor have to submit particulars of an instructed variation under FIDIC 2017?

Under Sub-Clause 13.3.1 of the 2017 Red, Yellow and Silver Books, the Contractor submits detailed particulars, including proposals for modifying the programme and adjusting the Contract Price, within 28 days of receiving the instruction, or within another period proposed by the Contractor and agreed. The extension of time and price adjustment are then agreed or determined under Sub-Clause 3.7 of the Red and Yellow Books, or Sub-Clause 3.5 of the Silver Book, in which the Employer gives the instruction.

What are the notice periods for a claim under FIDIC 2017?

A Notice of Claim within 28 days after the claiming party became aware, or should have become aware, of the event under Sub-Clause 20.2.1, and a fully detailed Claim within 84 days under Sub-Clause 20.2.4, unless the Engineer agrees another period. The 1999 forms allow 42 days for the fully detailed claim. If the statement of legal basis is not given within 84 days, the Notice of Claim is deemed to lapse, subject to the Engineer’s notice.

Can the Engineer waive FIDIC notice requirements?

In Uniform Building Contractors v WASA the Privy Council held not, under the 1999 conditions. Sub-Clause 3.1 gave the Engineer no authority to amend the contract or relieve either party of its obligations, so any waiver had to come from the Employer and be pleaded and proved. That decision states the law of Trinidad and Tobago; the position in an Indian dispute is a separate question of Indian law.

Is an oral variation instruction valid under FIDIC?

The 1999 conditions require instructions in writing, but the Privy Council declined to hold an oral instruction automatically invalid, since both parties could waive the requirement. It noted that contractors routinely protect themselves with a Confirmation of Verbal Instruction sent to the Engineer. The safer course is to confirm every oral instruction in writing before the work starts.

Can a contractor price a variation or delay claim by formula in an Indian arbitration?

A formula can calculate a loss that is proved, but it does not prove the loss. In Unibros v All India Radio, 2023 INSC 931, the Supreme Court upheld the setting aside of an award of loss of profit computed by Hudson’s formula because the evidence substantiating the loss was missing. Contemporaneous cost, resource and programme records are what turn a formula into evidence.

11. How R & D Law Chambers Works on These Matters

R & D Law Chambers LLP is an Ahmedabad law firm. We advise on Indian law only, for businesses anywhere, wherever a matter has an India connection.

The practice advises employers and contractors on variation, notice and claims procedures under FIDIC-based and bespoke EPC contracts, from contract administration and correspondence during the works to claims before the Engineer, arbitration, and challenges to awards under section 34 of the Arbitration and Conciliation Act, 1996. That work sits within the firm’s EPC contract advisory and dispute resolution practice.

Related services and reading

• EPC Contract Lawyers: Advisory and Dispute Resolution Across India: drafting, execution-phase notices and disputes on EPC contracts.
• International EPC Advisory: FIDIC book selection, Particular Conditions and cross-border EPC disputes.

 

This article is for informational purposes only and does not constitute legal advice. It states the position as at 29 September 2026. FIDIC forms are licensed documents, and the clause the parties actually signed, including any Particular Conditions, governs. Specific matters should be referred to qualified advisers.