Final Account Disputes: A Complete UK Guide

A final account dispute arises when the contractor and the employer cannot agree the final sum payable for completed construction work. The final account is the last, definitive valuation of everything done under the contract — the original price adjusted for variations, remeasurement, loss and expense, extensions of time, retention and any set-off. Disputes turn on the size of those adjustments, and they are resolved through negotiation, adjudication, and ultimately litigation or arbitration.

For most UK projects let on JCT or NEC forms, the gap between what the contractor claims and what the contract administrator certifies runs into tens or hundreds of thousands of pounds. Getting the payment-notice mechanics right under the Construction Act 1996 — and knowing when to launch a “true value” adjudication rather than a “smash and grab” — is often worth more than the underlying valuation argument itself.

• The final account is the contractually adjusted final value of the works — not simply the original contract sum.
• Under JCT and NEC there is a defined procedure and timetable for agreeing it; miss the deadlines and figures can become conclusive.
• The Construction Act 1996 payment and pay-less notice regime governs whether and when the notified sum must be paid, regardless of true value.
• A “smash and grab” adjudication enforces the notified sum on notice failures; a “true value” adjudication reopens the valuation — but only after the notified sum is paid (S&T v Grove [2018]; Bexheat [2022]).
• Common flashpoints include variations, measured/remeasured work, loss and expense, retention release, defects set-off and EOT/LADs.
• Most final account disputes are resolved by construction adjudication — a 28-day statutory process — before any court is involved.
• Limitation is six years for a simple contract and twelve for a deed, running from the breach (usually practical completion).

What the final account actually is

The final account is the definitive financial reconciliation of a construction contract: the contractually adjusted total that the employer must pay the contractor for all work performed. It is not the same as the original contract sum, the tender, or the last interim valuation. It takes the agreed starting figure and applies every adjustment the contract permits — additions and omissions for variations, remeasurement of provisional or approximate quantities, the valuation of dayworks, loss and expense for disruption and prolongation, fluctuations where applicable, and deductions such as liquidated damages and contra-charges for defects.

In JCT terminology this surfaces as the Final Statement (or Final Certificate under the traditional Standard Building Contract); in NEC4 it is the final assessment of the amount due. Whatever the label, the function is identical: to draw a line under the money. Once that line is drawn and the relevant conclusivity provisions bite, the parties lose the right to reopen most issues. That is why the final account is the single most contested document on many projects — it crystallises every disagreement that was parked during the build.

A well-prepared final account is a structured build-up: contract sum, plus and minus the value of variations, plus remeasured work, plus loss and expense, less retention not yet released, less liquidated damages, less the value of any defective work set off. Each line should be evidenced — variation instructions, measured quantities, programme records, and cost substantiation. Where the evidence is thin, the contract administrator will discount the claim, and the gap between claimed and certified opens up.

Agreeing the final account: JCT and NEC

Both major UK contract suites set out a defined procedure and timetable. Missing a step does not just delay payment — it can make figures conclusive against the party who fails to act.

The JCT route

Under the JCT Design and Build Contract 2016, the contractor has three months from practical completion to submit its Final Statement. If the employer does not dispute it in time — or fails to issue a valid payment notice within the required period and a pay-less notice where it intends to pay less — the Final Statement can become conclusive evidence of the sum due. The JCT Standard Building Contract uses a Final Certificate issued by the contract administrator that, once issued, is conclusive (subject to a short window) as to matters including the quality of workmanship where the contract states standards are for the architect’s approval, the adjustment of the contract sum, extensions of time and the reimbursement of loss and expense.

Crucially, the conclusive-evidence clause can be suspended only if adjudication, arbitration or other proceedings are commenced within the contractual window (commonly 28 days for proceedings, or a short period after the Final Certificate). The 2024 JCT editions tightened this: under DB 2024 the suspension of conclusivity on commencing proceedings is now a fuller suspension rather than being limited to the subject matter of those proceedings. The practical lesson is unforgiving — if you disagree with a Final Statement or Final Certificate, you must act within the contractual window or you may lose the argument permanently, however strong it was on the merits.

The NEC route

NEC4 ECC contains a dedicated final assessment mechanism. The Project Manager must make the assessment of the final amount due within four weeks after the Supervisor issues the Defects Certificate (or within thirteen weeks if a termination certificate is issued). If the Project Manager fails to assess within that period, the Contractor may issue its own assessment to the Client, and that assessment is treated as the final amount due unless the Client makes its own assessment within the timescale. NEC values change through compensation events assessed on the basis of Defined Cost plus Fee, so a NEC final account is largely the cumulative effect of agreed (or assessed) compensation events plus the priced work.

Interim vs final payment regimes: why the difference matters

Throughout the works, the contractor is paid by interim payments — monthly or stage valuations of work done to date, each subject to the Construction Act payment-notice rules. The final account is conceptually different: it is the once-and-for-all reconciliation. But the payment mechanics are the same. Section 111 of the Housing Grants, Construction and Regeneration Act 1996 (the “Construction Act”) applies to both interim payments and payments due on completion or termination. That is the source of much confusion — and much opportunity.

The key practical distinctions are these. An interim payment is provisional and can be corrected in the next cycle; an overpayment one month is recovered the next. A final payment is, by definition, the last cycle — there is no “next month” to correct an error, which is why notice failures at final account stage are so financially dangerous. And because the final account aggregates the whole job, the sums in dispute are larger, the evidence older, and the appetite to litigate higher.

Common causes of final account disputes

Final account gaps almost always come from a recurring set of heads. Understanding which head is driving the gap tells you what evidence you need and which forum is likely to help.

• Variations and their valuation. Disputes over whether an instruction was a variation at all, whether contract rates apply, and whether “fair valuation” or star rates should be used for work not contemplated by the priced document.
• Measured and remeasured work. Where quantities were provisional or the contract is remeasurable, disagreement over the as-built measure can move large sums. Accurate site records and agreed measures are decisive.
• Loss and expense. Money for disruption and prolongation caused by employer “Relevant Matters” — late information, variations, changes of access. This is distinct from a variation: a variation pays for different work; loss and expense compensates for the cost consequences of being delayed or disrupted. It is the head most often under-evidenced and therefore most often discounted.
• Retention release. Retention is typically released in two tranches — half at practical completion and the balance after making good defects. Disputes over whether defects have been remedied, and whether the Notice of Completion of Making Good has been (or should be) issued, delay the second release.
• Defects and set-off. Employers contra-charge the cost of remedying alleged defects against the final account. Whether the alleged defect exists, who caused it and the reasonable cost of remedy are all live.
• Extensions of time and liquidated damages. If the contract administrator awards less EOT than the contractor claims, the employer can levy liquidated and ascertained damages (LADs) for the unexcused overrun, deducting them from the final account. EOT and LADs are two sides of the same coin and routinely decide six-figure sums.

The Construction Act 1996 payment regime

The payment regime in Part II of the Housing Grants, Construction and Regeneration Act 1996 — as amended by the Local Democracy, Economic Development and Construction Act 2009 — is the spine of every UK construction payment, including the final account. Three sections matter most.

• Section 110A — the payment notice. The contract must require a payment notice specifying the sum the payer considers due and the basis of its calculation, given not later than five days after the payment due date. This can be a payer’s notice or, where the contract allows, a payee’s default notice.
• Section 111 — the requirement to pay the notified sum. The payer must pay the “notified sum” on or before the final date for payment, unless it has served a valid pay-less notice. This applies to interim payments and to payments due on completion or termination alike.
• The pay-less notice. To pay less than the notified sum, the payer must serve a pay-less notice before the prescribed period ends, specifying the sum it considers due and the basis of calculation. Miss it, and the full notified sum becomes payable regardless of true value.

The architecture is deliberate: it secures cash flow — “the lifeblood of the construction industry” — by making the notified sum payable on a strict timetable. If the payer wants to dispute value, it must do so through the notice mechanism or, failing that, recover any overpayment later through a true value adjudication. You can read the statutory wording on the requirement to pay the notified sum at legislation.gov.uk and the surrounding regime in Part II of the 1996 Act.

Smash and grab vs true value adjudications

This is the most commercially important distinction in final account disputes, and the case law is now settled.

A “smash and grab” adjudication asks one narrow question: did the payer serve a valid payment notice and pay-less notice in time? If not, the adjudicator orders payment of the full notified sum — the figure in the contractor’s application — without examining whether the work is actually worth that much. It is a procedural knockout based on the notice regime, not the merits of the valuation.

A “true value” adjudication asks the opposite question: what is the work genuinely worth on a proper valuation? It reopens the figures.

The relationship between the two was fixed by the Court of Appeal in S&T (UK) Ltd v Grove Developments Ltd [2018] EWCA Civ 2448. The court held that an employer can commence a true value adjudication to challenge an interim valuation — but only after it has first complied with its immediate obligation to pay the notified sum under section 111. The payment provisions in section 111 take priority over the adjudication right in section 108: you must pay first, then argue value. This deliberately curbed abusive “smash and grab” tactics while preserving the paying party’s route to a proper valuation.

The Technology and Construction Court reinforced this in Bexheat Ltd v Essex Services Group Ltd [2022] EWHC 936 (TCC). O’Farrell J confirmed that section 111 creates an immediate obligation to pay the notified sum, and that a party cannot rely on, or set off, an earlier true value decision to defeat that obligation. In short: the immediate payment obligation trumps the entitlement to commence or rely upon a true value adjudication. Pay the notified sum first; recover any overvaluation afterwards.

Worked example: anatomy of an £80,000 gap

Limitation: how long you have to claim

Limitation sets the long-stop for bringing a claim. Under the Limitation Act 1980, an action founded on a simple contract must be brought within six years (section 5), and an action on a contract executed as a deed within twelve years (section 8). Time runs from the date the cause of action accrued — for a construction breach, usually practical completion, or the date of the relevant breach. A contractor chasing an unpaid final account is therefore typically working to a six- or twelve-year window depending on how the contract was executed.

Two practical points. First, check whether your contract is a deed: it materially doubles the window. Second, adjudication has no statutory limitation bar of its own — you can adjudicate at any time — but the underlying contractual right you are enforcing remains subject to the Limitation Act, and a respondent can raise limitation as a defence. Note also that the Building Safety Act 2022 extended limitation for certain building-safety defect claims, but that is a specialist regime separate from the ordinary final account position. You can review the primary text in the Limitation Act 1980 on legislation.gov.uk.

How to escalate a final account dispute

Final account disputes follow a recognised escalation ladder. Most never reach the top rung.

1. Negotiation and account meetings. Sit down with the certifier, work head by head, and agree what can be agreed. The objective is to narrow the gap to the genuinely contested items before incurring formal costs. A well-prepared, evidenced account does most of the work here.
2. Mediation or expert determination. Where direct talks stall, a neutral can break the deadlock cheaply and confidentially — particularly useful where the relationship matters.
3. Adjudication. The default for construction money disputes. Either party can refer at any time. The adjudicator must reach a decision within 28 days of the referral, extendable by 14 days with the referring party’s consent and longer by agreement. The decision is binding and enforceable pending final determination — fast, comparatively cheap, and decisive.
4. Litigation or arbitration. If a party wants to overturn an adjudicator’s decision, or seeks a final binding result, it goes to the Technology and Construction Court (or to arbitration where the contract so provides). Enforcement of an adjudicator’s decision is itself usually obtained by summary judgment in the TCC.

Enforcing and challenging adjudication decisions

An adjudicator’s decision is enforced in the TCC, typically by summary judgment, and the courts enforce on very limited grounds — broadly, a lack of jurisdiction or a serious breach of natural justice. In S&T v Grove and the line of cases that followed, the courts confirmed that a true value decision cannot be relied upon until the smash and grab sum has been paid, and that narrow Part 8 challenges (for example, a self-contained legal point about the timing or validity of a payment or pay-less notice) can be run in parallel with enforcement. The message for final account disputes is consistent: cash flow first, valuation second.

Common mistakes to avoid

What we see in practice

Across the final account disputes we advise on, the gap between the parties rarely sits in the original contract sum — it concentrates in three heads: the valuation of variations, loss and expense for prolongation and disruption, and contra-charges deducted for alleged defects. The contract sum is usually common ground; the adjustments are where the argument lives. Parties who keep a contemporaneous, head-by-head record of those items — rather than reconstructing them months after practical completion — consistently negotiate from a stronger position.

The second pattern is procedural. Since the Court of Appeal’s decision in S&T (UK) Ltd v Grove Developments Ltd [2018] EWCA Civ 2448, a payer who misses the pay-less notice deadline must pay the notified sum first and can only claw back any overpayment through a later true-value adjudication. That sequencing usually decides who holds the cash — and the leverage — while the valuation is argued out. We regularly see contractors win a “smash and grab” on the notices alone, only for the figure to be reopened on true value, which is why getting the notice regime right at interim stage is almost always cheaper than fighting it out at final account.

How Hayhills can help

Hayhills Legal Advisory works with contractors, sub-contractors and employers to resolve final account disputes commercially and quickly. We act directly on the work that decides most accounts: reviewing your JCT or NEC contract and the payment/notice position, building or rebutting the account head by head, devising payment and pay-less notice strategy, and running or defending adjudications — including the critical smash-and-grab versus true-value sequencing under Grove and Bexheat. We also handle mediation, expert determination and negotiated settlement.

Where a dispute must move to court enforcement, insolvency or contested TCC litigation, those are reserved or court-based steps: here we provide the strategy and document review and introduce and coordinate a regulated solicitor so you have one joined-up team. Talk to us before the conclusivity clock runs down.

Frequently asked questions

This article is for general information only and does not constitute legal or accountancy advice. Hayhills Limited, trading as Hayhills Legal Advisory, provides non-reserved legal advisory services. Always check current requirements at GOV.UK.