As-Built Drawings
A final set of drawings updated to show what was actually constructed, including every field change, substitution, and adjustment made along the way, rather than just the original design intent.
Why it matters
What actually gets built rarely matches the original plans exactly: a wall shifts a few inches, a pipe gets rerouted around an obstruction. As-built drawings are the record of reality, and they're often the only way anyone can safely renovate or repair the building years later without guessing what's actually behind a wall.
On a real project
During construction, a plumbing line gets rerouted around a structural beam that wasn't shown correctly on the original drawings. The as-built drawings mark exactly where that line actually runs, so nobody drills into it during a future renovation.
Who this matters most to
A Project Engineer is usually responsible for tracking every field change throughout the project and rolling them into the final as-built set. A Facilities Manager relies on those drawings for years afterward: they're often the only accurate map of what's actually behind the walls.
Where this goes wrong
A contractor treats as-built drawings as a low-priority afterthought and hands over a set that's barely been updated from the original design. Years later, a maintenance crew drills into a wall exactly where the plans show nothing, hitting a rerouted electrical line that was never actually documented, causing an outage and a repair bill that accurate records would have prevented entirely.