Why this matters

Interim payment turns construction progress into money. Errors can arise from duplicated quantities, unapproved variations, materials not properly secured or percentages that do not match physical work.

Before work starts

Agree measurement rules and submission dates at the start. Drawings, site measurements, delivery records and approved rates should support the contractor’s claim.

What to watch on site

The certifier should record adjustments and distinguish completed work from materials on site. Retention, advance-payment recovery and previous certificates must reconcile.

Handover and the lasting record

Keep the claim, assessment, certificate and proof of payment as one audit trail. The final account is easier when interim decisions remain visible.

Editorial note

This practical article explains a project-control issue using the official reference listed below. Requirements depend on the contract, site, approving authority and current law; the responsible registered professional should confirm the project-specific position.

What we will track next

The strongest follow-up to Payment certificates should trace quantities back to evidence is an auditable chain from decision to outcome. Scope, authority, quotation, approval, delivery and payment should agree, with changes recorded while the work is active.

Commercial records are project controls, not end-of-job paperwork. A current programme, cost forecast, instruction register and payment history let the team address risk early and give reviewers evidence for the final account.

Sources