Definition

As-Built Drawing

A drawing that records the structure or building as it was actually constructed, including any modifications made during construction, rather than as it was originally designed.

An as-built drawing (also called a record drawing) is a revised version of a construction drawing that reflects the actual built state of a structure or building, including all changes made during the construction process. Design drawings represent intent; as-built drawings represent reality. The gap between the two is often larger than clients expect.

During construction, deviations from the design occur for many reasons: site conditions that differ from those anticipated in the design (particularly in groundworks), coordination changes between structural, architectural, and M&E trades, value engineering adjustments, and contractor-initiated substitutions of specified materials or methods. If these changes are not systematically recorded and incorporated into a revised drawing set, the as-built condition of the building is undocumented.

Undocumented deviations create problems throughout the life of a building. Future maintenance or alteration work may proceed on the basis of the original design drawings without realising that the as-built condition differs — with potentially serious consequences. A structural alteration designed on the basis of a drawing that does not reflect the actual reinforcement arrangement, for example, may perform differently from predicted. Services maintenance may be complicated by routes that differ from those shown.

For inspection and survey purposes, the availability of accurate as-built drawings significantly improves the quality and efficiency of the work. An inspector who can verify that column C3 is at the grid reference shown on the drawing, and that it has the specified cover to reinforcement, can make confident assessment from external observation. An inspector working from design drawings that may or may not reflect the as-built condition must carry more uncertainty in their conclusions.

360° photographic surveys provide a partial remedy for missing or uncertain as-built records. A comprehensive panoramic survey of a building's structural frame — every bay, every level, from consistent positions — creates a visual as-built record that can be used to resolve ambiguities in the drawings and to provide context for future investigation.

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