As-Built Schedule

An as-built schedule records the actual execution history of a project: when each activity actually started, when it actually finished, and what the critical path actually was through delivery. It is produced retrospectively, typically for delay analysis purposes, by updating a schedule with actual data from progress records, site diaries, correspondence, and other contemporaneous evidence. A well-constructed as-built can be overlaid against the Accepted Programme to show where and why the project diverged from plan.

As-built schedules are the foundation of most retrospective delay analysis methods. Window analysis operates on sequential as-built snapshots; collapsed as-built (a variant) starts with the full as-built and removes specific delay events to assess their impact. The SCL Delay and Disruption Protocol recognises as-built-based methods as preferred for retrospective analysis, provided the as-built is itself defensible.

The challenge with as-built schedules is data quality. On projects that maintained disciplined progress updates through delivery, constructing an accurate as-built is mostly an assembly exercise. On projects where progress was reported inconsistently or constraints were used to paper over slippage, the as-built has to be reconstructed from primary evidence — site diaries, photographs, delivery notes, inspection records — which is expensive and opens the resulting as-built to challenge. Running disciplined schedule updates throughout delivery is what makes as-built analysis feasible later.