Shop Drawings vs IFC Drawings: A Practical Guide for Construction Professionals

Every construction project runs on documentation. Among the most important — and most confused — are shop drawings and IFC drawings. Professionals across architecture, engineering, and contracting encounter both regularly, yet the distinction between them often gets blurred on site.

That confusion has consequences. When teams misunderstand which document governs fabrication and which governs construction, errors multiply. Rework becomes inevitable. Costs climb.

This guide sets the record straight. Whether you are a contractor reviewing submitted documents, a quantity surveyor tracking design changes, or a site engineer coordinating trades, understanding the role of each drawing type will make your project run more smoothly.

What Are IFC Drawings?

IFC stands for Issued for Construction. IFC drawings are the final, approved set of construction documents that the design team releases to the contractor to build from.

They represent the completed design — reviewed, coordinated, and signed off by architects, engineers, specialist consultants, and in many cases the relevant regulatory authority. Once a drawing carries the IFC status, it has passed every approval gate. The contractor is authorised to proceed based on its content.

What IFC Drawings Contain

IFC drawings cover the full scope of the project design. A complete IFC package typically includes:

•       Architectural layouts, elevations, and sections

•       Structural drawings with member sizes, connections, and load details

•       MEP systems — mechanical, electrical, and plumbing coordination

•       Specifications, notes, and material schedules

•       Dimensions, tolerances, and compliance references

Together, these documents answer one fundamental question: what needs to be built, and to what standard?

The Legal Weight of IFC Documents

IFC drawings are not simply technical guidance — they form part of the contract documents. They establish what the contractor is obligated to deliver, and they serve as the primary reference in any dispute, inspection, or compliance review.

On most projects, the general contractor will not mobilise for full-scale construction without a complete IFC set in hand. Any work built ahead of IFC approval carries risk — if the design changes during the approval process, that work may need to be redone. For more on how documentation drives cost control in the early stages of a project, see our guide on BOQ preparation and construction cost planning.

What Are Shop Drawings?

If IFC drawings define what gets built, shop drawings define how specific components get made.

Shop drawings are detailed fabrication documents prepared by contractors, subcontractors, suppliers, or specialist manufacturers. They zoom in on individual elements of the project and translate the design intent from the IFC set into the precise instructions needed for production.

A structural steel fabricator does not go directly from the IFC structural drawings to cutting steel. They prepare shop drawings first — showing exact member lengths, connection plate dimensions, bolt patterns, weld specifications, and hole placements. Only once these drawings are reviewed and approved does fabrication begin.

Who Prepares Shop Drawings

Unlike IFC drawings, which come from the design team, shop drawings are produced by the people responsible for making and installing each component. Depending on the trade, this could be:

•       A steelwork fabricator producing connection details and erection drawings

•       A reinforced concrete subcontractor preparing bar bending schedules and rebar layouts

•       A mechanical contractor detailing ductwork fabrication and equipment connections

•       A glazing supplier producing curtain wall component drawings

•       A millwork manufacturer showing cabinetry dimensions and fixing details

Each specialist brings trade-specific knowledge that the design team does not always have — and shop drawings are where that knowledge gets formally documented.

The Approval Process

Shop drawings are not self-approving. Once prepared, they must be submitted to the architect or engineer of record for review. The design team checks that the proposed fabrication approach aligns with the IFC intent — not that it copies the IFC drawing, but that it achieves the same design outcome.

Once the design team returns the drawing as approved or approved with comments, fabrication can proceed. If the shop drawing is rejected, revisions are required before production starts.

Shop Drawings vs IFC Drawings: The Core Differences

The clearest way to understand the distinction is to compare them across the dimensions that matter most in practice.

The simplest summary: IFC drawings tell everyone what the finished building must look like and how it must perform. Shop drawings tell the fabricator exactly how to produce each piece of it.

Neither document can replace the other. A contractor without an approved IFC set has no authorised design to work from. A fabricator without approved shop drawings has no confirmed production instructions.

How the Two Documents Work Together on a Real Project

The relationship between IFC drawings and shop drawings is sequential — one follows the other. Understanding that sequence helps every member of the project team manage their responsibilities correctly.

Here is how it typically unfolds on a mid-size commercial building:

•       The design team completes all coordination and issues the IFC package to the contractor

•       The contractor reviews the IFC drawings and begins procurement and planning

•       Each subcontractor and fabricator prepares shop drawings for their scope

•       Shop drawings are submitted to the design team for review — usually against a submission schedule

•       Approved shop drawings trigger material ordering and fabrication

•       Installation proceeds on site in line with the approved shop drawings and the IFC intent

Consider a concrete example. The IFC structural drawings specify a 600mm deep steel beam at a particular grid location, with connection details referenced to a standard detail sheet. The steel fabricator takes that information and prepares a shop drawing showing the exact cut length, the connection plate dimensions, the bolt hole pattern, and the weld preparation required. The structural engineer reviews the shop drawing, confirms it matches the design intent, and approves it. The fabricator then produces the beam.

Without the IFC drawing, the fabricator has no design basis. Without the shop drawing, the engineer has no fabrication proposal to review. Both are necessary.

In projects using Building Information Modelling, this process becomes even more tightly integrated. BIM models allow fabricators to extract precise geometry directly from the coordinated design, reducing manual interpretation errors. For more detail on how digital tools are changing this workflow, see our article on BIM and Quantity Surveying: How Digital Models Are Changing Cost Planning.

Where IFC Drawings Sit in the Full Documentation Lifecycle

IFC drawings do not appear out of nowhere. They are the end product of a long design process that begins with concept sketches and progresses through several intermediate stages.

•       Concept design: Early sketches and massing studies used to test ideas

•       Developed design: More detailed drawings used for cost planning and client sign-off

•       Tender drawings: Issued to contractors during the bid phase — not yet IFC status

•       IFC drawings: Final approved documents authorising construction

•       As-built drawings: Revised after construction to record what was actually built

One distinction worth noting: tender drawings and IFC drawings are not the same thing. A contractor who prices a job from tender drawings may later find that the IFC set includes changes. Those changes can affect programme, cost, and scope — which is why tracking the revision history of drawings is a critical part of project administration.

Contractors who understand the full documentation lifecycle are also better positioned to submit accurate and competitive bids. For a detailed breakdown of how documentation drives the tendering process, see How Contractors Can Win More Bids with Accurate and Fast Tendering.

Common Mistakes That Create Problems on Site

Most drawing-related disputes on construction projects trace back to a small number of recurring errors. Knowing them in advance makes them avoidable.

Building from Tender Drawings

Some contractors begin early site works or pre-order materials using tender drawings before the IFC set is released. If the design changes between tender and IFC — which it frequently does — that work may not conform to the final approved design. Remediation is expensive.

Fabricating Without Approved Shop Drawings

Starting fabrication before shop drawings receive formal approval is a risk that regularly turns into a problem. If the design team raises objections during review, already-fabricated components may need to be modified or replaced entirely.

Treating Shop Drawing Approval as Design Sign-Off

When an engineer approves a shop drawing, they are confirming compliance with design intent — not taking responsibility for the fabricator's production methods or measurements. Contractors sometimes interpret approval more broadly than it is intended, which creates confusion when installation problems arise.

Failing to Manage Drawing Revisions

Both IFC drawings and shop drawings can be revised during the project. Revision control — ensuring that everyone on site is working from the current revision — is one of the most common sources of construction errors. A robust document management process is not optional on any project of scale.

The site engineer plays a central role in managing drawing revisions and ensuring that works on the ground match the approved documentation. For a full breakdown of that function, see the Role of a Site Engineer in Construction: Practical Guide.

Why This Distinction Matters for Cost Control

Drawing management is not just a technical issue — it has direct financial consequences.

When shop drawings deviate from IFC intent and that deviation goes undetected through the approval process, it often results in on-site rework. Rework on a large project is not just a cost line — it compresses the programme, disrupts other trades, and can trigger delay claims.

When IFC drawings are issued late or issued in multiple packages without a clear revision schedule, contractors cannot plan fabrication lead times. Steel, precast concrete, specialist glazing, and custom MEP equipment all have long procurement cycles. Delays in IFC issue translate directly into delays on site.

Conversely, projects that manage their drawing workflows well — issuing IFC packages on a coordinated schedule, tracking shop drawing submissions against a register, and closing out comments quickly — tend to run closer to budget and programme than those that treat documentation as secondary to physical construction.