FIDIC extension of time: Sub-Clause 8.5, the 20.2 claim and the programme behind it
Updated: Oct 18
By Roman Bazelchuk | NEC Accredited Project Manager | APMG Project Planning and Control
Founder, NEC Planning Solutions Ltd
A FIDIC extension of time moves the Time for Completion, and Sub-Clause 8.5 of the 2017 Red and Yellow Books entitles the Contractor to one when completion is or will be delayed by a listed cause. Except for a Variation, it is claimed through Sub-Clause 20.2, starting with a Notice of Claim within 28 days.
On a FIDIC job, a claim for time turns less on whether the delay happened than on whether the Contractor can show it. The Engineer needs a Programme that was credible and kept current, records made at the time, and a claim made inside the periods Sub-Clause 20.2 sets. Those are the points where claims give way: the 2022 Global Construction Disputes Report ranked poorly drafted or unsubstantiated claims as the leading cause of construction disputes worldwide.
This guide takes the subject from the planner's side, for contractors working under the 2017 Red or Yellow Book: UK firms moving into European and international work, Baltic design-and-build and EPC teams on EU-funded jobs, and the planners who build the evidence. It covers the grounds, the claim procedure, what the Engineer does with a claim, the programme and records behind it, concurrent delay, the cost of not claiming, and what an EU grant adds on funded work.
References are to the second edition of the Red Book, published in 2017 and reprinted with amendments in 2022. The Yellow Book uses the same claims procedure, and the 1999 equivalents are set out near the end. Two guides go further on neighbouring ground: what Sub-Clause 8.3 requires of the programme, and how FIDIC and NEC differ for contractors.
The grounds for a FIDIC extension of time under Sub-Clause 8.5
Sub-Clause 8.5 entitles the Contractor to an extension of the Time for Completion to the extent that one of five causes delays, or will delay, completion under Sub-Clause 10.1, the taking-over clause. The test is delay to completion, not delay to an activity. And because a delay that will affect completion qualifies, the claim can be made while the delay still lies ahead.
The five causes are a Variation, a cause of delay that another Sub-Clause says gives an extension, exceptionally adverse climatic conditions, Unforeseeable shortages of personnel or Goods from an epidemic or governmental actions, and delay, impediment or prevention for which the Employer, the Employer's Personnel or the Employer's other contractors on the Site are responsible. Climatic conditions qualify only when they were Unforeseeable against the climatic data the Employer made available under Sub-Clause 2.5 or the data published in the Country. The shortages ground also covers Employer-Supplied Materials.
A Variation is the one cause that needs no claim. Sub-Clause 8.5 excuses it from Sub-Clause 20.2, and its effect on time is settled through the Variation procedure. Every other cause is claimed through 20.2, including the many Sub-Clauses that give time for a particular event, from late drawings to late access to the Site. Table 1 lists the common ones and what each gives the Contractor besides time.
Cause of delay | Sub-Clause | Time | Money |
A Variation | 8.5(a), 13.3 | Yes, with no Notice of Claim | Valued as a Variation |
Late drawings or instructions | 1.9 | Yes | Cost Plus Profit |
Late access to the Site | 2.1 | Yes | Cost Plus Profit |
Errors in the items of reference for setting out | 4.7 | Yes | Cost Plus Profit |
Unforeseeable physical conditions | 4.12 | Yes | Cost |
Archaeological and geological findings | 4.23 | Yes | Cost |
Delays caused by public authorities or private utilities | 8.6 | Yes | None stated |
Exceptionally adverse climatic conditions | 8.5(c) | Yes | None stated |
Shortages caused by epidemic or governmental actions | 8.5(d) | Yes | None stated |
Delay or prevention by the Employer or its other contractors | 8.5(e) | Yes | Not given by 8.5: the claim states its own legal basis |
Changes in laws | 13.6 | Yes | Cost |
Suspension by the Contractor, for example for non-payment | 16.1 | Yes | Cost Plus Profit |
Exceptional Events | 18.4 | Yes | Cost, for some events only |
A measured quantity more than 10 per cent over the Bill of Quantities (Red Book only) | 8.5 | Yes, where it delays completion | Extra work measured and paid under Clause 12, none stated for the delay |
Table 1: common causes of delay under the FIDIC 2017 Red Book and what each gives the Contractor. All are claimed under Sub-Clause 20.2 except a Variation, and the Particular Conditions can change any of them.
A Red Book contract adds a route of its own. Where the measured quantity of an item exceeds its estimate in the Bill of Quantities by more than 10 per cent and the increase delays completion, the Contractor is entitled to an extension. The Engineer may set against it the effect of items whose quantities fell by more than 10 per cent, but the net result cannot reduce the Time for Completion.
Extensions are cumulative. When a new one is agreed or determined, the Engineer reviews the earlier ones and may increase the total, but not reduce it. Money is a separate question. An extension moves the date from which the Employer's Delay Damages run, but Cost comes only where the Sub-Clause gives it, or where the claim states another legal basis for it, and it has to be proved from the records.
How to claim a FIDIC extension of time under Sub-Clause 20.2
Sub-Clause 20.2 runs the Contractor's claims for additional payment and extensions of time, and the Employer's claims too, through the same steps. Each step has a period, and each period runs from a fixed point, so a claim is as much a matter of dates as of substance.
The FIDIC Notice of Claim within 28 days
The claiming Party gives its Notice of Claim as soon as practicable, and within 28 days of the date it knew, or ought to have known, of the event or circumstance (20.2.1). The Notice describes the event. The days and the money come later. If it is late, the Contractor is not entitled to the extension or the payment and the Employer is discharged from liability, subject to the Engineer's 14 days and the late-submission review below.
A Notice is a formal document. Sub-Clause 1.3 requires it to be in writing and identified as a Notice, and the contract says that nothing in a progress report, a programme or its supporting report counts as one. A revised programme that shows the delay is evidence. It is not the Notice.
The Engineer's 14 days
If the Engineer considers the Notice of Claim late, it must say so by Notice, with reasons, within 14 days of receiving it (20.2.2). If it does not, the Notice of Claim is treated as valid. The Employer can still disagree, and its disagreement is then reviewed when the claim itself is agreed or determined. A late Notice is therefore not automatically fatal, but a Contractor relying on the Engineer's silence has traded an argument about the delay for an argument about the bar.
The fully detailed Claim within 84 days
Within 84 days of the same awareness date, or another period the Contractor proposes and the Engineer agrees, the Contractor submits a fully detailed Claim (20.2.4). It contains a description of the event, a statement of the Claim's contractual or other legal basis, all the contemporary records it relies on, and detailed particulars of the extension and any payment claimed. The legal basis is the item to watch. If that statement is missing when the period ends, the Notice of Claim lapses, and the Engineer must say so by Notice within 14 days, failing which the Notice of Claim is treated as valid.
Claims with a continuing effect
A long delay outlasts the 84 days. Where the event has a continuing effect, the fully detailed Claim is treated as interim, further interim claims follow at monthly intervals with the extension accumulated to date, and the final claim goes in within 28 days after the effects end, unless the Engineer agrees another period (20.2.6). For the planner that is a monthly cycle of its own, running alongside the monthly progress report.
When a late submission can still count
Where the Engineer has given Notice that a Notice of Claim was late, or that it lapsed because the legal basis came after the 84 days, the agreement or determination of the claim under Sub-Clause 3.7 also decides whether the Notice of Claim stands because the lateness was justified (20.2.5). The factors it may weigh include whether, and how far, the Employer would be prejudiced by accepting it, and what the Employer already knew of the event or of the legal basis. A revised Programme that showed the event, or an advance warning under Sub-Clause 8.4, is evidence of exactly that knowledge.
Agreement, determination and what follows
Sub-Clause 3.7 allows 42 days from the Engineer's receipt of the fully detailed Claim for the Parties to reach agreement through the Engineer's consultation, and a further 42 days for the Engineer's fair determination. A claim not determined in time is deemed rejected. A Party dissatisfied with a determination gives a Notice of Dissatisfaction within 28 days, failing which the determination becomes final and binding, and the Dispute is then referred to the Dispute Avoidance/Adjudication Board within 42 days of that Notice, or the Notice lapses. In the meantime, the Engineer includes in each Payment Certificate the amounts reasonably substantiated (20.2.7).
PLANNER'S TAKEAWAY Before the 28 days run out, add the event to the latest revised Programme, linked to the activities it affects, and record the effect on completion. Serve the Notice of Claim, then submit that programme as the next revision under Sub-Clause 8.3. It becomes the first exhibit of the fully detailed Claim, and evidence of what the Employer knew. |
The programme evidence behind the claim
FIDIC prescribes no method for working out how long an extension should be. The Engineer decides on the evidence, and for a claim for time the evidence is the programme: whether it was credible at the start, whether it was kept current, and whether the event can be traced through its logic to a change in completion.
The Programme is the version that has passed the Engineer's review under Sub-Clause 8.3, by a Notice of No-objection or by the Engineer's silence. It is not one of the documents forming the Contract (1.5), but the Contractor proceeds in accordance with it, and the Contractor revises it whenever it no longer matches actual progress or conflicts with the Contractor's obligations. A revised Programme shows actual progress and the delays to it, and its supporting report sets out the Contractor's proposals to overcome their effects. The guide to Sub-Clause 8.3 sets out the full list.
The SCL Delay and Disruption Protocol, widely used as guidance though it binds no one, asks the parties to deal with the time effect of each Employer Risk Event as the work proceeds, as close to the event as they can, rather than waiting to see. A common way to do that is a time impact analysis: the event is modelled as a fragnet, a short chain of linked activities, inserted into the latest revised Programme before the event, and the programme is rescheduled to measure the effect on completion. For analysis after the event the Protocol prefers no single method: the choice turns on factors including the contract, the nature of the events and the project, the records and programme information available, the time available and the forum. The delay analysis guide compares the methods.
A worked example shows the arithmetic. The Contract Data gives access to the pump station area on 2 May. The latest revised Programme, issued on 31 March, shows the pump station chain finishing with 10 days of total float to completion. Access is given on 13 June, 42 days late. Inserted as a fragnet, the late access moves the end of the chain by 42 days, so completion moves by 32: the float absorbs the first 10. The claim is for 32 days under Sub-Clause 2.1, with the Cost of the delay plus profit under the same Sub-Clause, proved from the records. Figure 1 shows both programmes on one time axis.
Records carry the rest. Sub-Clause 20.2.3 treats as contemporary only the records made at the time of the event or immediately afterwards. The Engineer may monitor the Contractor's record-keeping and instruct it to keep more, without that implying that it accepts the records as accurate or complete. The monthly progress report under Sub-Clause 4.20 compares actual with planned progress, records the events that may affect completion and the measures taken to overcome delays, and supports each interim payment application. A report is not a Notice, but a run of them is the account against which an Engineer, and later a Board, will test the claim's dates.
NEC Planning Solutions builds and tests FIDIC extension of time claims from the native programme files and the project records, starting with a fixed-fee position review completed within a week of receiving the files. On one FIDIC job it built the logic-linked baseline and kept the change register that quantified the programme impact of design changes. See delay and extension of time analysis and the case study.
Concurrent delay under Sub-Clause 8.5
Sub-Clause 8.5 leaves concurrency to the parties. Where a delay for which the Employer is responsible runs concurrently with one for which the Contractor is responsible, the extension is assessed under whatever rules and procedures the Special Provisions of the Particular Conditions set out or, if they set out none, as is appropriate in all the relevant circumstances. The standard form sets no method, so the outcome depends on what the Special Provisions say and on the governing law.
The law pulls in different directions. English courts have generally allowed the full extension where the two delays are truly concurrent, Scottish courts have apportioned, and civil law systems have no single rule, though several, including the UAE and France, lean towards apportionment. Parties can also write their own answer. In North Midland Building v Cyden Homes [2018] EWCA Civ 1744 the Court of Appeal upheld an amended JCT clause under which concurrent delay gave no extension, and held that the prevention principle does not stop parties agreeing that. The SCL Protocol takes the opposite default, that the Contractor's concurrent delay should not reduce the extension due, and treats true concurrency as rare.
For the Contractor, the work is done at tender and in the records. Read the Special Provisions at tender, because a clause that excludes concurrent delay moves the risk to the Contractor. On site, keep the Contractor's own delays and the Employer's in separate records and separate programme activities, so the claim can show which one was driving completion at each point.
COMMERCIAL CONSEQUENCE Where the Special Provisions exclude concurrent delay, a Contractor delay running alongside an Employer delay can leave no extension for the overlap. The Employer can then claim Delay Damages under Sub-Clause 8.8 for those days, up to the maximum in the Contract Data. That exposure belongs in the tender price. |
Acceleration, Delay Damages and the cost of not claiming
An extension that is not claimed, or not proved, costs the Contractor twice. Under Sub-Clause 8.7, if progress is too slow to complete within the Time for Completion, or is behind the Programme or about to fall behind it, for a reason that is not an 8.5 cause, the Engineer may instruct a revised Programme and supporting report showing how the Contractor will expedite. The Contractor adopts those methods at its own risk and cost.
Delay Damages are the second cost. If the Contractor fails to complete within the Time for Completion, the Employer is entitled, subject to Sub-Clause 20.2, to Delay Damages at the daily rate stated in the Contract Data, up to the maximum stated there (8.8). Each day of extension the Contractor proves moves the Time for Completion and takes a day's damages off the total. Where the delay does come from an 8.5 cause and the Engineer instructs acceleration to reduce it, the instruction is a Variation under Sub-Clause 13.3.1 and is paid as one.
Extensions of time on EU-funded FIDIC projects
FIDIC, or national conditions built on it, is widely used on EU co-funded transport works in Poland, Romania and the Baltic states, though not everywhere. Rail Baltica's contract strategy uses the Red Book for construction-only works and the Yellow Book for design-and-build systems. Latvia procured its mainline construction on the 2017 Red Book, with the Engineer appointed on the White Book, and the line's electrification contract, signed in September 2025, is based on the 2017 Yellow Book. Estonia has moved its mainline to alliance contracts, so check the form lot by lot.
The funding adds a second set of rules. On a Connecting Europe Facility grant the beneficiary is the Employer or the body it delivers for, such as a national ministry, and the grant agreement requires the beneficiary to keep its records for five years after the final payment, open to checks and audits by the granting authority, the European Commission, OLAF, the European Public Prosecutor's Office and the European Court of Auditors. The beneficiary must also make sure those bodies can exercise the same rights over the contractors carrying out the action. The EU Financial Regulation, recast in 2024, requires anyone receiving EU funds to cooperate with those bodies, and under cohesion policy the managing authority must make sure documents are kept for five years from 31 December of the year of its last payment to the beneficiary.
Delay has a funding consequence of its own. The CEF Regulation lets a grant be reduced, amended or terminated where works have not started within two years of the agreed start date, or where a progress review finds delays serious enough that the objectives are unlikely to be met, and CINEA, the agency that runs the programme, expects extensions of a works action, in principle, to total no more than 24 months. An Employer watching its grant end date has its own reason to test each day of extension claimed.
The scale is real. The European Court of Auditors found in 2020 that eight EU-funded transport megaprojects were running an average of 11 years late, and its 2026 follow-up put the average delay at 17 years for five of them, with Rail Baltica's estimated cost almost four times the first estimate. On jobs like these, a claim that cannot be followed from event to entitlement on the documents alone will be tested by more people than the Engineer.
If your contract is on the 1999 books
Contracts let on the 1999 Red and Yellow Books are still running. There the grounds sit in Sub-Clause 8.4, which in the Red Book adds a substantial change in an item's quantity to a Variation, and delays by public authorities sit in Sub-Clause 8.5. Claims run through Sub-Clause 20.1. The notice is due within 28 days of awareness, and a late one leaves the Contractor with no extension and discharges the Employer, with no 14-day objection period or late-submission review, though the governing law can temper it. The fully detailed claim follows within 42 days, and the Engineer responds within 42 days of receiving it, approving or disapproving with detailed comments. Extensions there too can be increased on review but not reduced.
The author's view
In my view the 28-day bar gets the attention and the programme decides the outcome. The 2017 edition softened the bar through the Engineer's 14 days and the late-submission review, and that review weighs what the Employer already knew. A Contractor whose revised Programmes showed the event as it happened has that evidence before it writes a word of the claim. One that kept a static baseline and a bar chart for the monthly report has to rebuild the story after the event, against the 84-day clock.
So I treat the 28 days as a planning deadline, not a commercial one. The planner who sees an event land should impact it the same week, tie it to the activities it moves, and hand the commercial team a number and a record rather than a suspicion. On funded work I would go one step further and build each claim file as if an auditor will open it without a meeting, because on EU money one can. That was the discipline on that FIDIC job: a logic-linked baseline, a change register that quantified the programme impact of design changes, and weekly reporting that kept the record current.
The argument in short
A FIDIC extension of time under the 2017 Red and Yellow Books needs a cause listed in Sub-Clause 8.5, delay to completion under Sub-Clause 10.1, and a claim made through Sub-Clause 20.2: a Notice of Claim within 28 days and a fully detailed Claim, legal basis included, within 84. The claim is agreed or determined under Sub-Clause 3.7 within 42 days and a further 42, and a claim not determined in time is deemed rejected, which opens the route to the Dispute Avoidance/Adjudication Board.
The method is left open, so the evidence decides: a Programme revised whenever it stops reflecting progress, an impacted programme for each event, contemporary records made at the time, and monthly progress reports that tell the same story. Concurrency follows the Special Provisions and the governing law. On EU-funded work the same file may also have to satisfy the grant's auditors, for five years after the final payment.
Download the FIDIC extension of time checklist
A two-page check for the claim file: the programme position under Sub-Clause 8.3, the Notice of Claim and the Engineer's 14 days, the fully detailed Claim and its legal basis, continuing effects, concurrency and the Special Provisions, and the records an Engineer and a funding audit will ask for. Direct download, no sign-up.
FIDIC extension of time: frequently asked questions
What are the grounds for an extension of time under FIDIC 2017?
Sub-Clause 8.5 of the 2017 Red and Yellow Books lists five: a Variation, a cause another Sub-Clause says gives an extension, exceptionally adverse climatic conditions, Unforeseeable shortages of personnel or Goods from an epidemic or governmental actions, and delay, impediment or prevention for which the Employer, its Personnel or its other contractors on the Site are responsible. The delay must reach completion under Sub-Clause 10.1, now or later.
How long do you have to give a FIDIC Notice of Claim?
Sub-Clause 20.2.1 of the 2017 books requires a Notice of Claim as soon as practicable, and within 28 days of the date the Contractor knew, or ought to have known, of the event. A late Notice is treated as valid unless the Engineer gives Notice within 14 days that it was late (20.2.2), though the Employer can still dispute that, and lateness can be found justified under 20.2.5.
What must a fully detailed FIDIC EOT claim contain?
Under Sub-Clause 20.2.4 it contains a description of the event, a statement of the Claim's contractual or other legal basis, all the contemporary records relied on, and detailed particulars of the extension and any payment claimed. It is due within 84 days of awareness. If the legal basis is missing by then, the Notice of Claim lapses, unless the Engineer fails to say so within 14 days.
Does a Variation need a Notice of Claim for an extension of time?
No. Sub-Clause 8.5 lists a Variation as a ground for an extension of time and says that no claim under Sub-Clause 20.2 is needed for it. The time effect is settled through the Variation procedure instead. Every other ground, including the many Sub-Clauses that give time for a particular event, is claimed through 20.2, starting with a Notice of Claim within 28 days.
How does FIDIC 2017 deal with concurrent delay?
Under Sub-Clause 8.5, where an Employer delay and a Contractor delay are concurrent, the extension is assessed under the rules the Special Provisions of the Particular Conditions set out or, if they set out none, as is appropriate in all the relevant circumstances. The standard form sets no method, so the Special Provisions and the governing law decide, and records that separate the two delays carry the argument.
What happens if the Engineer does not respond to an extension of time claim?
Sub-Clause 3.7 allows 42 days from the Engineer's receipt of the fully detailed Claim to reach agreement and a further 42 days for the Engineer's determination. If no determination is given in time, the claim is deemed rejected. A Party dissatisfied with a determination, actual or deemed, gives a Notice of Dissatisfaction, then refers the Dispute to the Dispute Avoidance/Adjudication Board within 42 days of that Notice.
What changed for extensions of time between FIDIC 1999 and 2017?
The 1999 books put the grounds in Sub-Clause 8.4 and the procedure in Sub-Clause 20.1: a notice within 28 days, with a late one barred, then a fully detailed claim within 42 days. The 2017 edition keeps the 28 days but tempers the bar through the Engineer's 14 days and the late-submission review, allows 84 days for the fully detailed Claim, and refers concurrency to the Special Provisions.
About the author
Roman Bazelchuk is the Founder of NEC Planning Solutions Ltd, a UK project planning and controls consultancy supporting contractors with NEC programme compliance, compensation event assessments and live project controls. He is an NEC Accredited Project Manager and holds the APMG Project Planning and Control qualification, with a BEng in Mechanical Engineering and postgraduate training in Planning and Control.
NEC Planning Solutions provides contract-aware planning support through a QA-governed delivery model, helping project teams keep programmes accepted, current and commercially useful from tender through to live delivery.
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