What Are Shop Drawings in Construction?
Shop drawings are detailed drawings prepared by a contractor, fabricator or supplier — not the original architect or engineer — showing exactly how a specific element will actually be made and installed. They translate a design drawing’s intent into fabrication-ready detail: precise dimensions, connections, materials and fixing methods the design drawings never show. Before fabrication starts, shop drawings are submitted back to the architect or engineer for review and approval, confirming the proposed method matches the design intent. They matter most for elements manufactured off-site to tight tolerances — structural steel, precast concrete, joinery, curtain wall and similar trades — where a mistake caught on a drawing is cheap, and the same mistake caught after fabrication is not.
Key takeaways
- Shop drawings are prepared by the contractor, fabricator or supplier building the element — not by the original architect or engineer.
- They show fabrication-ready detail — exact dimensions, connections, materials and fixing methods — that design drawings do not include.
- Shop drawings must be submitted and approved before fabrication begins, catching errors on paper instead of in steel, joinery or precast.
- Shop drawings differ from as-built drawings: shop drawings show what is planned before work starts, as-builts show what was actually constructed once finished.
What are shop drawings?
Shop drawings are the detailed, fabrication-level drawings a contractor, fabricator or supplier produces to show precisely how they intend to make and install a specific element of the works. They sit between the architect’s or engineer’s design drawings and the physical object being built.
The name comes from where these drawings originate: the fabricator’s workshop, or “shop,” rather than the design office. A structural steel fabricator, precast concrete supplier, joinery workshop or curtain wall installer each produces their own shop drawings for the elements they are responsible for building.
In plain terms
Shop drawings are the fabricator’s own working drawings — proof, before anything gets cut or cast, that what they are about to build actually matches what was designed.
Shop drawings vs design and construction drawings
Design drawings describe what is required — dimensions, materials, performance and appearance. They rarely show every fabrication detail, because the architect and engineer are not the ones making the element.
Shop drawings fill that gap. Produced after the design drawings by the party actually fabricating the element, they add bolt sizes, weld types, panel joints, hardware and exact setting-out dimensions.
| Design drawings | Shop drawings | As-built drawings | |
|---|---|---|---|
| Prepared by | Architect / engineer | Contractor / fabricator / supplier | Contractor, updated at completion |
| Shows | Design intent, dimensions | Fabrication and installation detail | What was actually constructed |
| When produced | Before construction | Before fabrication | At project close-out |
The shop drawing approval process
Shop drawings go through a formal submission and review cycle before fabrication is allowed to start, because an error caught on paper costs nothing next to the same error discovered in cut steel or cast precast.
- The fabricator or subcontractor prepares the shop drawing based on the design drawings and specification.
- It is submitted to the head contractor, who checks it against the contract documents before forwarding it on.
- The architect or engineer reviews it against the design intent and any structural or performance requirements.
- It comes back approved, approved with comments, or rejected — comments or rejection mean revision and resubmission before fabrication proceeds.
How My Trade Hub keeps drawing-driven trades on track
My Trade Hub’s automated quantity takeoff and tender preparation tools work from the same uploaded plans that shop drawings are later developed from, so the quantities, rates and tender documents you prepare stay traceable back to a specific drawing revision.
For trades where shop drawing detail drives the price — structural steel, joinery, precast and similar specialist work — keeping your priced Bill of Quantities and tender documentation in one place makes it far easier to track which drawing revision a rate was actually built against.
Frequently asked questions
Who prepares shop drawings — the architect or the contractor?
The contractor, fabricator or supplier building the specific element prepares shop drawings — not the original architect or engineer. The architect or engineer then reviews and approves them before fabrication begins.
What is the difference between shop drawings and construction drawings?
Construction drawings describe the design intent — dimensions, materials, performance requirements. Shop drawings add the fabrication-level detail needed to actually build a specific element, and are produced after the construction drawings, by the fabricator.
Why do shop drawings need approval before fabrication?
Approval confirms the fabricator’s proposed method, dimensions and materials genuinely match the design intent before anything is manufactured. Catching an error on a shop drawing is inexpensive; catching it after fabrication usually means costly rework.
Which trades rely most heavily on shop drawings?
Trades that manufacture elements off-site to tight tolerances rely on them most — structural steel fabricators, precast concrete suppliers, cabinetmakers and joiners, and curtain wall or glazing installers.
What is the difference between shop drawings and as-built drawings?
Shop drawings are produced before fabrication and show what is planned to be made and how. As-built drawings are produced at project completion and show what was actually constructed, including any variations from the original design.
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