Coordination drawings are composite drawings produced by the trade subcontractors that overlay ductwork, piping, conduit, and sprinkler mains on the structural and architectural backgrounds at a common scale. Each trade draws its own layer, a lead coordinator combines them, and the trades resolve conflicts and sign the composite before fabrication and installation start.
Helonic reviews the 2D design set for cross-discipline conflicts before coordination starts, so the trades begin with fewer known problems.
Last reviewed October 2026 by Milind Sagaram
The three get confused because they can look alike on screen. The difference is who draws them and what question each one answers.
| Design drawings | Shop drawings | Coordination drawings | |
|---|---|---|---|
| Who produces it | Architect and engineers of record | One trade subcontractor or fabricator | All trades in a space, combined by a lead coordinator |
| What it shows | Design intent, sizes, and performance, often diagrammatic for MEP | How that trade will fabricate and install its own work | Every trade's routing and elevation together, at one scale |
| Who reviews it | Building department, owner, and contractor | Design team, for conformance with the contract documents | The trades and the GC sign it; the design team often reviews for information only |
| When it happens | Before bid and permit | After award, before fabrication | After award, usually before the related shop drawings and before install |
| Typical spec home | The contract drawings themselves | Section 01 33 00 and each trade section | Section 01 31 00, repeated in Division 21, 22, 23, and 26 sections |
Design MEP drawings are often single-line and say “coordinate in field” or “route as required.” Coordination drawings are where someone finally decides the route. The shop drawing review guide covers the single-trade submittal that usually follows.
A coordination drawing shows every trade that occupies a space on one sheet, at one scale, with elevations. A typical sheet covers a floor area or a mechanical room at 1/4 inch or 3/8 inch scale and shows duct, hydronic and plumbing piping, cable tray and large conduit, sprinkler mains and branch lines, and the structure they all have to fit under.
The requirement usually lives in the specifications. Division 01, often MasterFormat Section 01 31 00 (Project Management and Coordination), tells the contractor to prepare coordination drawings where limited space calls for it. The mechanical and electrical sections in Divisions 23 and 26 often repeat it with trade-specific rules, such as minimum scale or which items must appear. Read both, because the trade section can be stricter than Division 01.
Specs vary on whether the design team reviews the drawings. Many say the architect reviews them for information only, which keeps responsibility for routing with the contractor.
The trade subcontractors draw them, and one party combines and manages the process. On most commercial jobs it splits like this:
The order matters. Gravity piping and large duct usually get placed first because they have the least flexibility, and conduit and smaller pipe go in last.
On most large projects today, coordination drawings come out of a federated BIM model. Each trade models its work, the coordinator runs clash detection, the group resolves clashes in weekly meetings, and 2D coordination sheets are cut from the model for sign-off and field use. The BIM execution plan usually sets the model standards, the clash rules, and who owns each step.
Smaller projects still overlay 2D trade drawings in CAD and resolve conflicts by eye. Either way, the output the field builds from is a signed set of coordination drawings.
Model-based clash detection only checks what the trades modeled. It can't tell you that the design set never left room for the duct in the first place. That kind of conflict sits in the 2D design drawings, and 2D clash detection on the design set can surface it before trade modeling starts.
The coordination meeting prep guide covers how to run step five without losing half the meeting to items nobody prepared.
Start with elevations, because most coordination failures are vertical. Two systems can look fine in plan and still occupy the same 6 inches of ceiling space. Use this list on each area before you sign:
Before you sign an area, trace the deepest point: the largest duct crossing under the deepest beam. If that crossing works with hangers and insulation drawn, most of the area will.
Coordination drawings resolve how trades share space the design allowed. When the design set itself has a conflict, such as a duct main drawn through a transfer beam or a ceiling height that leaves no plenum, the trades spend meeting time finding a design problem and then wait on an RFI.
Catching those earlier is part of a standard construction drawing review. The cross-discipline coordination guide lists the design-stage conflicts that most often carry into trade coordination, and the MEP coordination article covers how they appear on the MEP sheets.
Helonic reads the 2D design PDFs across architectural, structural, mechanical, plumbing, electrical, and fire protection sheets and flags cross-discipline conflicts with the sheet and location. Teams use it before trade coordination so known design conflicts go out as RFIs early. The clash detection feature explains what it compares.
Helonic does not produce coordination drawings or replace the trade sign-off. Findings are decision support, and the design team decides what changes. For where this sits in a full review, see how to review construction drawings.
Practitioner insight
“We'd hand the mechanical sub backgrounds and start meetings two weeks later. The first few always went to stuff that was wrong in the design set, like a main with no way past a transfer girder. That should have been an RFI a month before.”
Conversations with GC VDC and MEP coordination managers on hospital, lab, and mid-rise commercial projects.
Milind is the co-founder and CEO of Helonic, where he leads product and go-to-market for AI-powered construction drawing analysis. He works closely with general contractors, project managers, estimators, and owners to understand how drawing quality drives project outcomes - and where AI can reduce RFIs, change orders, and rework. Milind has interviewed hundreds of construction professionals across project delivery roles, from preconstruction estimators at ENR top-400 contractors to facilities directors at institutional owners, and uses those conversations to shape both product direction and the way Helonic talks about the work.
How this page was researched: Spec references were checked against MasterFormat Section 01 31 00 (Project Management and Coordination) and typical Division 23 and 26 coordination drawing language. The sequence reflects common GC-managed MEP coordination on commercial projects.
Last reviewed by Milind Sagaram · October 2026
Related references for trade coordination and drawing review.
Where the design disciplines conflict before the trades ever draw.
Agenda, prep, and follow-up for the sign-off meetings.
The single-trade submittal that follows coordination.
Lights, diffusers, sprinklers, and devices in one ceiling.
How MEP conflicts show up in the design set.
A systematic approach to catching drawing errors before construction.