Construction drawings (the design or contract drawings) are prepared by the architect and engineers and define what is to be built. Shop drawings are prepared by the contractor, subcontractor or fabricator to show exactly how one part of the work will be made and installed. As-builts are prepared after the work to record what was actually built. Construction drawings are part of the contract. Shop drawings normally are not: they are submittals reviewed against the contract, and a reviewed shop drawing does not supersede the contract drawings unless a deviation was flagged and accepted in writing.
For structural steel and rebar, the difference matters every day. Fabricators build from shop drawings, but the contract is measured against the design drawings. This post explains how the three relate, where responsibility sits, and what to watch when they disagree.
The three drawings side by side
| Construction drawings | Shop drawings | As-builts | |
|---|---|---|---|
| Prepared by | Architect, structural and other engineers | Contractor, subcontractor, fabricator or their detailer | Contractor (mark-ups), sometimes compiled by the consultant as record drawings |
| When | Before tender and construction | After contract award, before fabrication | During and after construction |
| Purpose | Define what is to be built and to what standard | Show how a specific part will be made and installed | Record what was actually built |
| Contract status | Part of the contract documents | Submittals, normally not contract documents | Closeout deliverable |
| Who reviews | Building department for permit; issued for construction by the designer | Consultant reviews for conformance with design intent | Owner and consultant receive at closeout |
| Typical content | Plans, sections, member sizes, typical details, notes, specifications | Every piece with dimensions, holes, welds, bar marks, quantities | Changes clouded or marked, final locations and sizes |
Construction drawings: design, architectural and IFC
"Construction drawings" is a broad term. On a typical project the set includes architectural drawings (layout, finishes, openings), structural drawings (members, reinforcement, connections in principle), and mechanical and electrical drawings, plus the specifications. People also call these design drawings, contract drawings or, at the permit stage, working drawings.
Drawings go through stages. A set may be issued for permit, for tender, and finally issued for construction (IFC). The IFC set is the one fabricators and detailers work from. If the structural drawings are still marked "for review" or "preliminary", shop drawings prepared from them are at risk of changing.
Construction drawings deliberately leave the fabrication details to others. A structural drawing might show a W-shape beam between two grids with a top of steel elevation and a connection reaction, or a wall with 15M bars at a spacing each face. It does not give the cut length of the beam, the bolt pattern of the clip angle, or the bar marks, lengths and bends. That is the shop drawing's job.
Shop drawings: what they add
Shop drawings translate the design into instructions a shop and a site crew can follow:
- Structural steel: erection drawings showing where each piece mark goes, assembly drawings for each shipping piece with plates, holes, welds and dimensions, anchor bolt layouts, and material lists.
- Rebar: placing drawings showing where each bar goes, and bar lists giving each bar mark's size, grade, shape, dimensions and quantity.
Our post on shop drawings vs fabrication drawings breaks down the steel drawing set, and rebar placement drawings covers what contractors need from rebar placing drawings.
Shop drawings are reviewed by the design team before fabrication. That review checks that the detailer has interpreted the design correctly. It is not a redesign and it does not transfer responsibility for dimensions, fit and quantities from the contractor to the consultant. For rebar, the RSIC Manual of Standard Practice describes the structural engineer as the final decision maker who approves, approves with corrections or disapproves the proposed details, while the detailer prepares them to interpret the design intent.
Are shop drawings contract documents?
On most Canadian projects, no. Standard contract forms, such as the CCDC 2 stipulated price contract used widely in Ontario, list the contract documents in the agreement itself, typically the agreement, the general and supplementary conditions, the specifications and the drawings issued by the consultants. Shop drawings are something the contractor provides during the work, under a shop drawing clause in the general conditions and a submittal section in the specifications.
That status has practical consequences:
- Shop drawings show how the contractor will meet the contract. They are evidence of compliance, not a new set of requirements.
- The consultant's review is limited. Under the usual wording, the review is for general conformance with the design concept, and it does not relieve the contractor of responsibility for errors in the shop drawings or for meeting the contract documents.
- Your contract may differ. Some owner-written contracts and design-build agreements treat submittals differently. Read the definitions and the shop drawing clause in your own contract.
Do shop drawings supersede contract drawings?
No. A shop drawing that differs from the contract drawings does not change the contract just because it was reviewed. The normal rule in Canadian practice is:
- The contractor must point out deviations. If a shop drawing departs from the contract documents, for example a substituted section or a different connection type, the contractor flags it clearly in writing.
- The consultant must accept the deviation expressly. A deviation buried in the drawing and not called out is not accepted just because the drawing came back "reviewed".
- Changes to cost or time go through a change. If the deviation affects price or schedule, it is handled as a change order or change directive, not by a review stamp.
In practice that means the fabricator builds from the reviewed shop drawings, but if something built from them does not match the contract drawings and the difference was never flagged and accepted, the contractor generally carries the risk. This is why good detailers send questions instead of guessing, and why a clear deviation note on a shop drawing protects everyone.
Our post on whether shop drawings need an engineer's stamp in Ontario explains the separate question of when a shop drawing must be sealed, and how a seal differs from a review stamp.
As-builts and record drawings
As-builts record what was actually built. On a steel or concrete project they capture:
- Field changes such as relocated openings, added members, shifted anchor bolts or extra bars.
- Revisions issued during construction through site instructions and changes.
- Final dimensions and elevations where they differ from the design.
Terminology varies. Many contractors use "as-builts" for their own marked-up drawings and "record drawings" for the clean set the consultant or contractor compiles from them at closeout. The specifications usually say which is required and in what format.
For steel and rebar, the shop drawing set is often the best starting point for the as-built record, because the erection drawings and placing drawings are revised as field changes happen. Keeping those revisions current, clouded and numbered makes the as-built set much easier to produce. Our post on the shop drawing process from IFC to fabrication includes a simple log for tracking revisions.
Working drawings vs shop drawings
"Working drawings" is used two ways. In Ontario residential and permit work, it often means the full construction set submitted for the building permit and used to build. In some trades and in other countries, it means drawings close to shop drawings, showing how a part is made. When someone asks for working drawings, confirm which they mean before you start.
Practical tips for contractors
- Detail from IFC drawings only, and record the drawing revision on every shop drawing.
- Answer the detailer's questions quickly. Most shop drawing delays are open questions, not drafting time.
- Flag deviations in writing on the drawing and in the transmittal.
- Keep one current set. Pull superseded prints off the shop floor and the site.
- Start the as-built record early, by marking up changes as they happen rather than at closeout.
Shop drawings prepared in-house
We prepare shop drawings in-house for the structural steel and rebar we fabricate, from your issued drawings, and engineering services are available for projects that need them. Take-offs and quotes are free. Send your drawings to get started, or see our services.
Frequently asked questions
What is the difference between shop drawings and construction drawings?
Construction drawings are prepared by the architect and engineers and define what is to be built; they form part of the contract. Shop drawings are prepared by the contractor, subcontractor or fabricator to show exactly how a specific part of the work will be made and installed, and they are submitted for review.
Are shop drawings contract documents?
Normally no. On most Canadian projects the contract documents are the agreement, conditions, specifications and drawings issued by the consultants. Shop drawings are submittals that show how the contractor intends to meet those documents. Check the definitions in your own contract.
Do shop drawings supersede contract drawings?
No. A reviewed shop drawing does not change the contract. A deviation from the contract documents has to be pointed out by the contractor and accepted in writing by the consultant, or processed as a change. Otherwise the contract documents govern.
What is the difference between shop drawings and as-builts?
Shop drawings are made before fabrication to show how something will be built. As-builts are made after construction to record what was actually built, including field changes. Shop drawings revised for field changes often feed into the as-built record.
