A structural engineer asked to assess an existing steel mezzanine for a new tenant finds the approved shop drawings in the project file, but no record of the connection changes made during erection. The drawings show what was planned. The frame shows what was built.
That gap is the difference between as-built drawings and shop drawings, two document types often confused because both describe the same steelwork at different moments. Understanding the difference matters for anyone who issues, reviews, or inherits project documentation, since using one in place of the other leads to rework and risk on later alterations. This guide explains what each contains, how one feeds the other, and what to ask for at handover.
Key Takeaways
- Shop drawings are prepared before fabrication to show how steelwork will be made and installed. As-built drawings are prepared after construction to record what was actually built.
- As-built drawings capture site changes, approved variations and field modifications that earlier shop drawings could not show.
- On steel projects, as-built records usually start from the approved shop drawings, updated with marked-up site changes that the engineer has reviewed where structural adequacy is affected.
- As-built drawings are not the same as the fabricator’s compliance records under AS/NZS 5131, which cover traceability, welding and inspection rather than geometry.
- Format, responsibility and timing for as-built documentation should be agreed in the contract or specification, not left until handover.
What Are Shop Drawings?
Shop drawings, also called fabrication or workshop drawings, are prepared before fabrication begins. They take the engineer’s design drawings and translate them into piece-by-piece detail: member lengths, hole positions, weld types, bolt lists and piece marks that a workshop can cut, drill and weld from, and that erectors can assemble from on site.
They are forward-looking documents. They describe how the steelwork is intended to be made, and they are normally reviewed and approved by the design team before fabrication proceeds. Because they are issued before the work happens, they cannot reflect anything that changes afterwards, however carefully they were checked.
Revisions are normal. A set commonly goes through several issues as requests for information (RFIs) are answered and coordination with other trades is resolved, which is why the revision status on a shop drawing matters as much as its content.
What Are As-Built Drawings?
As-built drawings, also called record drawings, document the work as it was actually constructed, including every change made along the way. On civil, subdivision and other council-regulated works, the same idea is commonly called work as executed (WAE) or as-constructed documentation.
On a steel project, that typically means recording revised connection details, additional plates or stiffeners, holes slotted or drilled on site, substituted members and engineer-approved variations. The information is gathered from site mark-ups (often called red-lines), responses to RFIs and approved variations, then drafted into a clean, issued set.
Their purpose is long-term rather than immediate. As-built drawings are not used to build from. They give owners, building managers and engineers a reliable reference for maintenance, structural assessments and future alterations, and depending on the contract, they usually form part of the handover documentation.
As-Built Drawings vs Shop Drawings: The Key Differences
The two document types differ in more than timing.
- Timing: shop drawings are issued before fabrication and revised as the job progresses. As-built drawings are compiled during construction and finalised near handover.
- Purpose: shop drawings instruct how steelwork is to be made and installed. As-built drawings record how it was made and installed.
- Content: shop drawings show intended dimensions, connections, welds and piece marks. As-built drawings show actual conditions, site changes and approved variations.
- Audience: shop drawings are used by the workshop, erectors and the engineer reviewing them. As-built drawings are used by owners, building managers, engineers and future contractors.
- Status: shop drawings are approved before work proceeds. As-built drawings are checked for accuracy against what was built, rather than approved for construction.
Both trace back to the design drawings, but they sit at opposite ends of fabrication. One tells the workshop what to make. The other tells the next person what was made.
How Shop Drawings Become As-Built Drawings
On structural steel jobs, as-built records usually start from the approved shop drawings, because those already carry every piece mark, grid reference, and connection detail that a site mark-up needs to point to. The path from one to the other follows a consistent sequence.
- Shop drawings are approved, and fabrication and erection proceed from them.
- Changes arising on site, such as fit-up problems, clashes with other trades or RFI outcomes, are marked up against the relevant drawings.
- Where a change affects structural adequacy or design intent, the engineer reviews it and confirms it is acceptable.
- The marked-up changes are incorporated into the drawings, with revision and status updated to show they are record documents.
- The as-built set is checked against the mark-ups and issued as part of handover.
The quality of the final record depends almost entirely on step two. Mark-ups captured as changes happen are far more reliable than a set reconstructed from memory at the end of the job.
What a Reliable As-Built Set Should Include
A usable as-built set for structural steel does more than redraw the shop drawings with a new title block. It should show member sizes and locations as installed, connection details as constructed, and every site modification, each referenced back to the RFI, variation or non-conformance that approved it. That reference trail is what lets a later engineer judge whether a change was reviewed or simply made.
Revision control matters just as much. The set should be clearly marked as a record issue and tied to a date, so nobody mistakes a superseded fabrication drawing for the final record.
As-Built Drawings Are Not Fabrication Compliance Records
A third package of documents often gets lumped in with both: the fabricator’s compliance records. AS/NZS 5131 (structural steelwork: fabrication and erection) sets requirements for documentation and traceability that scale with the construction category, so records such as material certificates, welding records and inspection and test reports demonstrate that the steelwork was made to the required standard. Standards Australia publishes the standard and is the authoritative source for confirming which edition applies.
These records prove quality and traceability. They do not show geometry. A handover package may need both: as-built drawings to show what was built, and compliance records to show how it was made. The specification should state which are required, who provides them, and in what format.
Why Confusing the Two Creates Risk
Treating approved shop drawings as the project record is the more common mistake. The set predates erection, so any change made on site is invisible in it. An engineer designing an alteration from those drawings may rely on a connection that was never built as shown, or miss one that was added.
The reverse error also occurs. As-built drawings describe the structure as constructed, not as intended, so steel for an extension or retrofit should not be cut from them without checking dimensions on site. They are a reliable starting point for design, but not a substitute for measurement where tolerances matter.
Both mistakes become more likely when as-built documentation is left to the last week of a project. Treating it as a planned deliverable, with an owner and a date, is far cheaper than reconstructing the record after the site team has moved on.
Frequently Asked Questions
Are as-built drawings required on every project?
Not universally. Requirements depend on the contract, the specification and the authority involved. Councils and water authorities commonly require certified work as executed documentation for civil and subdivision assets, while on building projects the client or head contractor usually specifies what is needed. Check the contract documents early rather than assuming.
When should as-built drawings be prepared?
Progressively, rather than at the end. Capturing mark-ups as changes are made, then finalising the set around practical completion, keeps the record accurate and avoids a rushed reconstruction. The contract usually sets the date by which the final as-built set must be issued.
What file formats are as-built drawings usually delivered in?
PDF and DWG are the most common, and some councils specify both. Where a 3D model was used on the project, the client may also ask for the model or an IFC export. The specification should name the formats so the final set can be used by whoever inherits the building.
Do as-built drawings carry the engineer’s certification?
Not automatically. As-built drawings are normally compiled by the contractor or detailer from site records, so certification depends on the contract and the authority involved. Where an engineer or registered surveyor must certify the set, that requirement should be stated in the specification, since it affects who needs to verify what.
Is an as-built survey the same as an as-built drawing?
No. An as-built survey measures the physical position and levels of completed work, typically carried out by a registered surveyor on civil and subdivision works. An as-built drawing records the work and its changes, usually from mark-ups and project records. On projects where accuracy matters, such as retrofits, a survey or scan can be used to verify the drawing.
Keeping the Project Record Aligned With the Building
Shop drawings and as-built drawings are two ends of the same documentation chain. One captures the plan before the steel is made, and the other captures the result once the structure is standing. Each is accurate for its own moment, which is exactly why neither can stand in for the other.
The practical difference comes down to planning. Agreeing early who produces the as-built set, in what format, and with what review, and capturing site changes as they happen, turns the record from an afterthought into something the next engineer, owner, or contractor can actually rely on.
If your project needs fabrication-ready shop drawings, or as-built record drawings that incorporate site mark-ups into a final set, Citotech’s detailing team can prepare both to match what your fabricator, builder, and engineer need. You can reach out with your project details to talk through scope, formats, and timelines before drawings get underway.
