Which milestone after substantial completion?

• A. Start of construction.
• B. Warranty periods begin.
• C. Final payment is due immediately.
• D. Warranty periods begin and closeout milestones are triggered, and final payment is due after remaining items are completed.

Answer: (D)

Substantial completion marks the project moving from construction into closeout, with the responsibilities shifting toward finalizing the work and starting protections for the owner. Once substantial completion is reached, the warranty periods begin and the closeout milestones are triggered. This means the contractor’s warranties for labor and materials start, and required closeout activities—such as delivering warranties, manuals, certifications, and final documentation—are initiated. The final payment is not due immediately at substantial completion; it is due after the remaining items, often identified on a punch list, are completed and closeout requirements are satisfied. That combination—warranty periods starting and closeout milestones being activated, plus final payment pending completion of remaining items—best reflects what happens after substantial completion.