Every construction contract ends the same way, however it started: with a single document that says what’s actually owed, not what was originally priced. That document is the final account, and getting it over the line – agreed, signed, and converted into a final certificate – is usually the biggest unresolved commercial job left on a project once the works themselves are finished. It’s also where a QS’s running cost reports, variation valuations and claims management either pay off cleanly or come back to bite.
This guide works through what a final account actually contains, the evidence you need to assemble before you can even start, how the timetable differs under JCT, NEC and FIDIC, a practical sequence for getting one agreed, where it typically goes wrong, and how the equivalent final payment claim and final certificate work under Australia’s AS4000 and AS2124 forms.
What a final account actually settles
A final account is the agreed statement of the total sum due to the contractor once every adjustment to the original contract sum has been made. Per RICS’s Final Account Procedures guidance note, it typically resolves:
- Variations – omissions and additions valued at contract rates, or remeasured on site where a billed item is genuinely in doubt
- Provisional and prime cost sums – replaced with the actual final value of the work once it’s known
- Dayworks – priced against signed daywork sheets, not estimated after the fact
- Fluctuations – where the contract provides for them
- Loss and expense – agreed on its own merits and kept separate from the factual variation account
- JCT gives the contractor six months from practical completion to supply the contract administrator with every document reasonably needed to adjust the contract sum, and the contract administrator then has a further three months to ascertain the final adjustment. Design and Build adds a backstop: if the contractor doesn’t respond to the employer’s own assessment, the employer can finalise its figure two months after that.
- NEC doesn’t run a separate final account period at all – every compensation event is meant to be assessed and agreed as it happens, so the account is, in principle, already settled by the time the last compensation event’s own timescale runs out. NEC4 formalised the close-out itself as a Final Assessment under clause 53, deliberately dropping the older “final account” language: once the Defects Certificate is issued, the Project Manager has four weeks to assess the amount due; if it doesn’t, the contractor can issue its own assessment, which becomes payable three weeks later; and the resulting figure becomes conclusive unless a dispute is already under way.
- FIDIC’s Red and Yellow Books put a number on it too: the contractor submits a draft final statement to the engineer within 56 days of receiving the performance certificate, and the engineer is then required to agree or determine the amount due.
- Track it continuously, not at the end. Treat your latest cost report as a rehearsal of the final account rather than a separate exercise. If costs and compensation events have been captured properly throughout, the final figure should barely move.
- Confirm instructions as you go. An instruction that only gets written down at final account stage, long after the work was done, is the most common reason a variation ends up disputed.
- Keep loss and expense separate. Agree the factual, measurable parts of the account – variations, dayworks, remeasurement – before tackling the more subjective heads of claim, and add loss and expense once it’s settled rather than blending the two together.
- Hold final account meetings to close gaps, not reopen them. A final account meeting should resolve a handful of genuinely outstanding items and confirm valuation methods already discussed. If new positions are being introduced for the first time in that meeting, something earlier in the process has gone wrong.
- Audit before you sign. Check the arithmetic, ideally with a peer review, and keep every substantiating document audit-ready. If the account is ever challenged, that evidence is what a statutory adjudicator will actually be looking at.
- Get it in writing, signed by both sides. The final certificate can’t be issued until the account itself is agreed – settle the account, and the certificate follows.
- Uninstructed or late-confirmed variations, often surfacing only after practical completion, when memories of what was actually agreed on site have already faded.
- Missed contractual timescales – the JCT, NEC and FIDIC periods above aren’t guidance, they’re triggers, and letting them lapse routinely tips a negotiation into a formal dispute.
- Contra charges issued outside the proper process, bypassing the pay less notice regime the Housing Grants, Construction and Regeneration Act 1996 requires for any amount withheld from a sum otherwise due.
- Liquidated damages left vague or simply omitted from the statement, when any deduction needs to be clearly and separately worded.
- Overly broad “full and final settlement” wording, applied as a standard formula rather than considered on its own terms – it can unintentionally compromise claims against the wider design team as well as the contractor.
It typically excludes liquidated damages, VAT and interest, which are dealt with separately from the account itself rather than folded into the same figure.
The evidence you need before you can start
A final account is only as good as the paper trail behind it. RICS’s guidance lists what the contractor should be providing as a matter of course: substantiation for every variation figure, subcontractor quotations where relevant, signed daywork sheets, loss and expense claims broken down by head of claim, and a build-up of any fluctuations being claimed. None of this should be a scramble at the end – it’s what your cost value reconciliation should already be tracking month to month.
One habit does more than any other to keep the account clean: confirming every verbal instruction in writing at the time it’s given, not months later. JCT’s Standard Building Contract explicitly allows this through a confirmed verbal instruction under clause 4.3.2 – use it. RICS’s guidance names uninstructed and late-confirmed variations as the single biggest reason final accounts drag on, and it’s an entirely avoidable one.
The timetable depends entirely on the form
This is where the three major forms – covered in more detail in our NEC vs JCT vs FIDIC comparison – genuinely part company.
A practical sequence for getting it agreed
Where it goes wrong
A handful of patterns account for most final accounts that end up in dispute rather than simply signed off:
Australia runs its own final certificate regime
Australian standard forms tie the final reckoning to a similar idea on a different clock. Under AS4000-1997 clause 37.4, the contractor must lodge its final payment claim within 28 days after the end of the defects liability period – commonly 12 months from practical completion unless the contract says otherwise – covering, in AS4000’s own words, all other claims whatsoever in connection with the contract. AS2124-1992 clause 42.7 gives the same 28 days. The superintendent then has 42 days under AS4000 to issue the final certificate, and can do so even if the contractor never lodges a claim at all.
Once issued, the final certificate is stated to be conclusive evidence of accord and satisfaction between the parties – subject to specific exceptions: fraud, latent defects, a computational error, or a notice of dispute served promptly (7 days under AS4000, 15 days under AS2124). Australian courts have upheld these claim-bar provisions even where the result looks harsh, so the practical message mirrors the UK forms exactly: diarise the trigger dates, don’t mistake silence for agreement, and make sure the practical completion certificate itself is unconditional before the final-account clock even starts running.
What this means for you
Whichever form sits over the project, a final account is really a test of how well the cost control was run from day one. The accounts that close smoothly are the ones where variations were valued and confirmed as they happened, loss and expense was tracked separately rather than lumped in with everything else, and retention and defects were reconciled continuously instead of left for a single year-end exercise. The ones that drag into adjudication are, almost without exception, the ones where that discipline slipped somewhere along the way – so build the habits in now, long before anyone’s asking for a final account.