Note
Short Payment Certificate: What to Do
The payment certificate arrives and the number is lower than the invoice you submitted. Before calling the main contractor’s accounts team, spend ten minutes understanding which of three things happened. The right first move depends entirely on the cause.
Three reasons a payment certificate comes back short
Retention deducted correctly. Your contract requires the main contractor to withhold a percentage of each payment as a performance guarantee. The certificate is applying that clause to this stage, as it does to every other stage. This is expected, matches the contract rate, and needs no action beyond checking the arithmetic is right.
A line item disputed or deleted. The main contractor’s quantity surveyor has reduced or removed a specific item in your claim. This might be a quantity they measured differently from yours, a specification they say does not match the BOQ, or a variation item they say was already included in the original scope. A disputed line needs a written response with supporting documents.
A set-off applied against your account. The main contractor has charged a cost they incurred to your account: equipment hire you failed to provide, a cleaning charge, a damage claim, or, in some cases, a cost from another project on the same contract. A set-off is the most important cause to identify quickly, because silence can be read as acceptance.
How do you identify which reason applies?
Three documents settle this in under 20 minutes.
First, your contract’s retention clause. Does the deduction match the retention rate multiplied by this stage’s value? If yes, the arithmetic is the only thing to check.
Second, the payment certificate itself. Does it itemise the deduction? A QS adjustment appears as a specific BOQ item reference or a variation number. A percentage deduction off the gross is almost always retention. If the certificate does not itemise the reduction at all, ask the commercial manager for a written breakdown before responding to anything.
Third, any correspondence from the main contractor in the past 30 days. A set-off almost always appears in a letter, a LINE message, or a formal notice before it reaches a payment certificate. If you find no corresponding document, that absence is itself the starting point for your written request.
What is the right first move for each shortfall type?
Retention deduction: Confirm the rate and the base it was applied to match the contract wording. Record the withheld amount on your retention tracking sheet. File the certificate. No escalation needed.
Disputed line item: Write to the commercial team the same week the certificate arrives. Attach your supporting documents: the signed acceptance form, the relevant BOQ extract, and any site records for the work in question. State the quantity and rate you are claiming and the clause you are relying on. Ask for their written basis for the reduction. You are not escalating yet; you are opening a paper trail.
Set-off: Write to the commercial manager within three to five working days. Request the document authorising the charge and the contract clause that entitles the deduction. State your own record of the event in the same message. A set-off not acknowledged in writing from your side creates a precedent you did not intend to set.
A worked example: the partition subcontractor whose certificate arrived short
A ceiling and partition subcontractor submitted a stage two claim covering three floors of a commercial fit-out. The certificate arrived showing less than claimed. Nothing in the correspondence preceding it had flagged any issue.
The subcontractor checked the retention clause first: the rate applied was correct and matched every previous stage. That standard deduction accounted for most of the gap. The remaining shortfall was a line deletion: the QS had removed the ceiling grid installed in the server room on floor two, on the basis that the server room sat in a separate BOQ section not included in stage two.
The subcontractor located the server room reference in the stage two work description, pulled the corresponding BOQ extract, and sent both to the commercial team with a short cover note explaining the mapping. The QS confirmed the adjustment within four working days. The corrected amount appeared on the stage three certificate.
The shortfall was not a dispute. It was a mapping difference that a clear document reference resolved in under a week.
When is a shortfall worth formal escalation?
Two conditions suggest moving from a commercial query to a formal written claim.
The first is a repeated reduction of the same item after you have provided supporting documents. If the same line is adjusted a second time, on a separate stage, following a written response from your side, the basis is not administrative.
The second is a set-off with no corresponding document. If no letter, notice, or clause reference arrives on request, the deduction has no stated basis. A formal written claim referencing the contract’s requirements for a valid set-off notice is appropriate at that point.
Neither escalation requires stopping work or issuing a default notice. Both require dated written correspondence that becomes part of the project record.
What if the accounts team will not explain the deduction?
Address the request to the commercial manager, not the accounts team. Accounts processes what the commercial team instructs; they cannot explain a QS decision. A written request to the commercial manager by name, asking for a breakdown within five working days, is the opening step of any escalation trail.
Is re-invoicing for the higher amount the right move?
Issuing a credit note and re-invoice does not change the main contractor’s position on a disputed item. What changes their position is the supporting document behind the item. A re-invoice for the original amount with a cover letter referencing the supporting evidence is cleaner than a credit and reissue, and carries more weight when the matter is reviewed.
What if the same deduction appears on multiple stages?
A deduction that repeats is not an administrative error. Treat it as a standing dispute and write a cumulative response with all supporting documents attached. It is better to address a repeated deduction at stage three than to wait for the final account, when every historical item is on the table at the same time.
If you want to go through the payment certificates on your current projects and identify which reductions are standard and which need a written response, a 45-minute call is the right starting point. We open the documents together and mark what needs chasing from what does not.