Your Interim Payment Was Certified Short - Here's What to Do

The certificate lands and the number is wrong. You applied for the full value of work done, materials on site, and the variations you have been chasing for two months, and the certifier has knocked a third off it. The instinct is to treat this as theft. It usually is not. An under-certification is almost always a valuation disagreement dressed up as a payment, and how you respond in the next few days decides whether you recover the shortfall in this cycle, the next one, or never.

First, Separate the Valuation Dispute From the Payment Default

These are two different animals and confusing them is the most common mistake contractors make. A valuation dispute means the certifier looked at your application and formed a different professional view - they measured the concrete differently, they rejected a variation as not yet instructed, they discounted materials on site because the delivery notes were missing. That is a disagreement about how much is currently due. It is contestable, it is normal, and it is resolved through the contractual machinery. A payment default is different: it is the failure to pay a sum that has actually been certified. If the certificate says QAR 2.9 million and the Employer pays QAR 2.4 million, that half-million is a default on a certified amount, and your remedies escalate quickly - interest, suspension, and in extreme cases termination.

Why does the distinction matter so much? Because the remedies do not overlap. You cannot suspend work over a valuation disagreement - the certifier is entitled to their view until it is overturned, and downing tools because you dislike the number puts you in breach. But you can and should react firmly to non-payment of a certified sum. Read the certificate carefully before you decide which fight you are in. Most under-certifications are the first kind, which means the answer is not confrontation - it is a disciplined, documented response inside the monthly cycle.

Understand the Cycle You Are Operating In

Interim payment is a rolling monthly valuation, not a series of one-off settlements. Each application is cumulative: you value the total work done to date, subtract everything previously certified, and claim the difference. That structure is your friend when a certificate comes back short, because a value the certifier rejects this month does not disappear - it stays in the cumulative total and can be re-presented next month with better substantiation. An under-certification is rarely a final decision. It is a snapshot of what the certifier was willing to accept on the evidence in front of them at that moment. If you understand how the machinery works, you stop treating each shortfall as a loss and start treating it as an item carried forward. Our note on interim payment certificates and the monthly valuation cycle walks through the mechanics in detail, and it is worth internalising before you draft any response.

The practical consequence is that speed matters less than accuracy. You do not need to win the whole shortfall back in a single furious letter. You need to identify precisely why each line was cut, fix the evidence gap, and re-present. Under most standard forms the certifier is required to notify the amounts they consider due under the payment provisions - typically the Clause 14 machinery under FIDIC - and if the reasons are not clear on the face of the certificate, your first move is to ask for them in writing.

Find Out Exactly Why It Was Cut

You cannot fix what you cannot see. Before responding, break the shortfall down line by line and map each rejected or reduced item against a reason. There are only a handful of reasons a certifier under-certifies, and each has a different cure. Measurement disagreement - they made it less than you did - is answered with joint remeasurement or your detailed take-off. Rejected variations are answered by proving the instruction and the pricing, or by pointing to the clause that deems an instruction to have been given. Materials on site discounted for want of delivery notes or ownership evidence are answered by supplying exactly that. Disallowed sums against alleged defects are answered by closing out the defect or challenging the deduction.

The table below shows the most common causes and the correct response to each.

Reason for the cut | What it actually means | Your response Measurement dispute | Certifier remeasured lower | Joint remeasure, submit detailed take-off Variation not recognised | No instruction accepted | Prove the instruction and price, cite the variation clause Materials on site discounted | Delivery or ownership not evidenced | Supply delivery notes, invoices, vesting certificates Retention deducted | Standard holdback applied | Verify the percentage and cap are correct Contra-charge or set-off | Employer deducted for a cross-claim | Demand the basis in writing, dispute if unsupported

One item deserves special attention because contractors routinely misread it as an under-certification when it is contractual: retention. If the number looks light and part of the gap is the standard percentage held back, that is not a shortfall - it is the holdback mechanism working as designed, and it becomes recoverable at the defined milestones. Make sure you are not fighting a retention deduction as though it were an error. Our guide on how retention works and how to actually get it back explains where that money sits and how to release it.

Respond in Writing - and Preserve the Entitlement

Once you know why each line was cut, respond in writing, promptly, and without heat. The letter has one job: to put on record, clearly and specifically, that you dispute the valuation, on what grounds, and with what supporting evidence. Vague protest is worthless. State the item, the amount in dispute, the reason the certifier gave, and the reason that reason is wrong, with the document that proves it attached or referenced. Reserve your rights expressly. Confirm that the disputed value is carried forward into the next application. This is not about aggression - it is about creating a contemporaneous record that survives the passage of time, because the person who certified this month may not be the person who decides the dispute in a year.

Watch the clock. Many standard forms and almost all bespoke amendments attach time limits to disagreeing with a certificate or to referring a payment dispute onward, and those bars are unforgiving. A shortfall you fail to challenge within the contractual window can crystallise into an accepted valuation. The same discipline that governs notices generally applies here - the 28-day rule that kills more claims than any dispute is a reminder that entitlement is lost through silence far more often than through weak argument. Diarise the deadline the moment the certificate arrives.

Escalate Without Torching the Relationship

There is a sequence here, and jumping straight to the top of it is how contractors turn a recoverable shortfall into a relationship-ending war. Start at the working level: a remeasurement meeting with the certifier, evidence on the table, a genuine attempt to close the gap on the merits. Most under-certifications are resolved here, because most are honest disagreements that dissolve once the missing document appears. If that fails, escalate formally through the contract - a dispute notice, a referral to the engineer or the contractually named tier, and only then the adjudication or arbitration machinery. Each step should be firmer than the last, but none should be personal.

Tone is a commercial asset. The certifier and the Employer's team will be valuing your work every month for the life of the project. A contractor who challenges precisely, evidences thoroughly, and stays civil gets the benefit of the doubt next cycle. A contractor who treats every cut as an insult gets defensive certification and slow answers. Firmness and courtesy are not in tension - the strongest position is a well-documented claim delivered without rancour. When the numbers are large or the pattern of under-certification is persistent, bring in senior support early; our claims and recovery service exists precisely to recover certified and applied value without detonating the commercial relationship that keeps the project moving.

Frequently Asked Questions

Can I stop work if my interim certificate comes back short?

Not for a valuation disagreement. If the certifier has formed a different professional view of how much is currently due, that is a dispute to be resolved through the contract, and suspending work over it puts you in breach. Suspension rights generally attach to non-payment of a sum that has actually been certified and remains unpaid after the due date - under FIDIC that is the Clause 16 machinery. Check whether you are dealing with an under-valuation or a genuine payment default before you consider downing tools, because getting that wrong flips the breach onto you.

What is the difference between under-certification and non-payment?

Under-certification is the certifier valuing your work at less than you applied for - a professional disagreement about how much is due right now. Non-payment is the failure to pay a sum that has already been certified as due. The first is contestable through the valuation machinery and re-presentation next cycle. The second is a payment default that triggers interest and, if it persists, suspension and ultimately termination remedies. They feel identical when the bank balance is short, but the law treats them completely differently and so should your response.

Do I lose the money the certifier cut this month?

Usually not. Interim valuation is cumulative, so a value rejected this month stays in the running total and can be re-presented in the next application with better evidence. The shortfall is carried forward, not written off - provided you dispute it in writing within any contractual time limit and keep the substantiation alive. Where you can lose it is by staying silent past a time bar or by treating the certificate as final when it was only a snapshot of what the evidence supported that month.

How quickly do I have to respond to a short certificate?

Faster than you think. Check your contract for any period to dissent from a certificate or to refer a payment dispute - bespoke amendments frequently impose tight bars, and once the window closes the valuation can be treated as accepted. Even where no strict bar applies, respond within the current cycle so the disputed item is properly recorded before the next application. Diarise the deadline the day the certificate arrives and treat it as immovable rather than discovering it has passed.

Should I involve lawyers when a certificate is under-valued?

Rarely as the first step. Most under-certifications are evidence gaps resolved at a remeasurement meeting, and reaching for lawyers immediately signals a fight the certifier will meet in kind. Start with a precise, well-evidenced written response and a working-level meeting. Bring in senior contracts or legal support when the sums are material, the under-certification is a repeated pattern, or a genuine payment default has crystallised - at which point professional escalation protects both the entitlement and the sequence you need to follow to enforce it.

A short certificate is not a verdict - it is an invitation to prove your number, and the contractor who answers with evidence rather than outrage almost always recovers the difference.

Note: This article is general information about interim payment mechanics and is not legal advice on any specific certificate or contract - obtain tailored advice before disputing or acting on an under-certification.