Note
Settling the Subcontract Final Account
Most subcontractors treat a project as finished when the last installed stage gets accepted. The final account says otherwise. It is the formal process of agreeing the total contract value between both parties: original contract sum, plus approved variations, minus backcharges, plus or minus any other contractual adjustments. Until the final account is settled and signed, the contract is not closed.
That distinction matters because the final account is a negotiation, not a payment. A main contractor’s QS who accepted your stage payments along the way still has the authority to query quantities, dispute variation values, and introduce backcharges that never appeared on any interim certificate. Your ability to hold the outcome depends almost entirely on the documentation you assembled before the meeting begins.
What Does a Final Account Cover?
A final account covers the complete financial position of the subcontract from first instruction to practical completion. It typically includes four components.
The first is the original contract sum: the lump sum or schedule-of-rates value agreed at signing. The second is agreed variations, instructions that increased or reduced scope and carry a written agreement on value. The third is disputed or unresolved variations, scope changes where work was instructed and completed but the value was never formally agreed. The fourth is backcharges, costs the main contractor claims against you for defects rectified on your behalf, delays attributable to your work, or other defined items in the subcontract.
The final account certificate, once signed, records the total settled sum. In most Thai subcontracts, accepting the final payment without written objection is treated as agreement with the total. This is why the preparation happens before the document is issued, not after.
Why Do Final Accounts Get Delayed or Disputed?
Four patterns appear consistently.
Variations were instructed verbally during construction and the value was never confirmed in writing. The value is now a matter of recollection, and the two sides remember it differently.
Backcharges surface at final account that were never mentioned on any interim certificate. The main contractor introduces a claim for remedying defects or delay costs that you have no record of being notified about during the project.
Quantities drift between the BOQ and the as-built scope. Zone boundaries changed, specifications were revised, additional work was carried out under verbal instruction. The submission package does not trace each change back to a written instruction.
Time pressure is the fourth. A main contractor may push for quick sign-off before the defects liability period ends. A quick sign-off that leaves disputed items unresolved is a sign-off on the main contractor’s terms.
How Do You Build Your Final Account Package?
The package has three parts.
The first is a variations register: a single document listing every instruction that changed the scope, the date it was issued, the form it took (written instruction, email, LINE message), the work it required, and the agreed or claimed value. Each line should cite the document it comes from. If the instruction was verbal, the register should note the date, who gave it, and what contemporaneous record exists.
Consider a subcontractor installing fire protection across fifteen floors. Mid-project, the engineer revised the pipe specification for floors eleven through fifteen, requiring heavier-gauge material and additional support brackets. The instruction came as a site instruction form dated week fourteen. The subcontractor raised a variation notice the same week. By final account, both sides had a reference point: instruction number, date, and agreed scope. The value was still under discussion, but the existence of the variation was not. That is what a variations register does.
The second part is a backcharge response log: a record of any backcharge the main contractor raised, when it was notified, whether you disputed it, and on what basis. A backcharge raised for the first time at final account, with no prior written notification during the project, carries weaker standing than one raised and documented during construction.
The third part is a retention reconciliation: the total withheld across all interim certificates, compared against the subcontract’s retention clause and the practical completion certificate date. This establishes the amount due for release and the date from which any overdue retention accrues.
How Do You Handle Unresolved Variations at Final Account?
Unresolved variations are the most common reason final accounts drag past their expected close. The approach that works is to separate them clearly from agreed items. Submit the agreed component for payment and mark the disputed component as a subject for further discussion, without signing a final account that treats the total as settled.
This is different from refusing to engage. It is accepting what is agreed and keeping what is disputed explicitly open. Most subcontracts allow interim payment on agreed items while disputed items are under negotiation. Confirming this in writing before the final account meeting, not after, is what keeps the option available.
What Should Be in the Final Account Agreement Document?
A final account settlement document should state: the original contract sum, each agreed variation with its reference and value, each agreed backcharge with its reference and amount, the adjusted total, the amount already certified in interim payments, the outstanding balance due, and the retention amount being released.
Signing a document that omits the retention release amount, or one that refers to disputed variations as settled when they are not, leaves you in a weaker position than signing nothing. A one-page agreement with every figure stated is the protection.
When Should I Submit My Final Account Claim?
Submit your final account claim as soon as practical completion of your scope is certified. Most subcontracts contain a time limit for submission. Missing it does not forfeit your claim automatically, but it reduces your position and may give the main contractor grounds to apply a deemed acceptance of their own figures. Check your subcontract for the exact period.
Can Backcharges Appear at Final Account That Never Appeared on an Interim Certificate?
Yes, in many subcontracts. This is the aspect of final accounts that catches subcontractors most off guard. Your best protection is a clause requiring written notification of any backcharge within a defined period of the event that gave rise to it. If your subcontract does not contain that clause, the notification requirement falls back to the general conditions. Read that section before the final account meeting, not during it. A backcharge you first encounter across the table is harder to dispute than one you have had time to review.
What If We Cannot Reach Agreement on the Total?
Most subcontracts provide a mechanism for unresolved disputes: negotiation between senior representatives, then mediation, then arbitration or litigation. The final account negotiation itself is not the final word. If agreement on disputed items cannot be reached, the undisputed total can be settled and the disputed items referred under the contract’s dispute clause. Settling what is agreed does not mean surrendering the rest.
If a final account on one of your projects has been open for more than three months without movement, a 45-minute call is a practical starting point. We look at what is unresolved, what documentation exists, and what a realistic path to settlement looks like.