A cost plan becomes stale when it no longer describes the current scope, timing or delivery strategy. Updating only at fixed calendar intervals can miss the changes that actually drive cost.
At a glance
- Update at major design stages so approvals are based on current information.
- Trigger an interim update when scope, services, programme or procurement changes materially.
- Reconcile movement rather than replacing the previous total with a new number.
At major design milestones
Typical checkpoints include feasibility or concept, schematic design, design development, pre-tender and tender reconciliation. The exact stages vary by project, but each update should use the latest agreed design baseline.
Before a client approves the next stage, the budget should reflect the information being approved.
After material scope or area change
Additional floor area, basement growth, revised façade, new rooms, upgraded finishes, changed external works or client-requested scope should be incorporated promptly rather than left to the next formal issue.
The update should show the cost of the change separately where possible so the decision remains traceable.
When structure or services develop
Structural systems, authority requirements, mechanical plant, electrical capacity, fire services, hydraulics and vertical transport can move significantly as consultant design matures.
Large provisional allowances should be replaced with measured or consultant-informed amounts as information improves.
When programme or procurement changes
Delays can change escalation; acceleration can change preliminaries and productivity; staging can duplicate temporary works and site overheads. A change from traditional procurement to design-and-construct can also move design responsibility and risk allowances.
These are cost-plan changes even if the physical building looks the same.
Before and after tender
The pre-tender cost plan provides the benchmark for the market test. Once tenders are received, normalise them and reconcile the preferred tender against the cost plan, including exclusions, provisional sums, alternates and scope gaps.
That tender reconciliation should become the new commercial baseline for construction reporting rather than carrying forward an outdated pre-tender estimate.