What are final accounts (including final certificates)?

These draw a line of sorts under the contractual obligations owed by the parties to a contract to each other. As always the answer depends on what the sub contract actually says. Frequently under standard forms, and particularly JCT forms, final accounts also finalise (subject to formal proceedings) disputes under the contract – normally those arising from valuations, quality of work and decisions on extensions of time and loss and/or expense. That is why clauses dealing with final accounts often impose on the parties’ conclusion unless objection is made within a prescribed period. If you do not dispute the areas you disagree with, it may well be too late to argue these points. Disputing elements of the final account means in effect either adjudication or arbitration.