Project delivery

What are shop drawings in construction?

Shop drawings are detailed drawings prepared by a contractor, subcontractor, fabricator, or supplier that show exactly how a specific part of the work will be made, assembled, and installed, submitted for the design team's review before fabrication.

Two construction professionals compare an aluminum frame sample with shop drawings in a site office.
Check the proposed sample and coordinated drawings before releasing fabrication. AI-generated illustration.

Design drawings show what the building should be. Shop drawings show how a particular piece of it will actually be made. A steel fabricator draws every beam with its connections, bolt holes, and piece marks. A millwork shop draws each cabinet with dimensions, materials, and hardware. A fire sprinkler contractor lays out heads and pipe routing. These drawings go through the submittal process to the architect or engineer for review before anything is fabricated.

The federal construction clause on specifications and drawings describes shop drawings as drawings submitted by the contractor, a subcontractor, or a lower-tier sub that show how structural elements are built and assembled, or how materials and equipment are fitted and attached. Private contracts such as AIA forms use similar definitions.

How shop drawing review works

  1. The sub or supplier prepares the drawings based on the contract documents and field dimensions.
  2. The GC reviews and stamps them. It checks coordination with other trades and conformance with the contract. Under the federal clause, the contractor must check shop drawings for accuracy, completeness, and conformity before marking its own approval.
  3. The architect or engineer reviews them for general conformance with the design intent.
  4. They come back with a status such as approved, approved as noted, revise and resubmit, or rejected.
  5. Fabrication starts only after acceptable review.

A shop drawing example

Say a misc metals sub on a parking garage submits stair and rail shop drawings in week 6. The GC's project engineer notices the stair landing conflicts with a sprinkler main shown on the fire protection shop drawings. One RFI and a revised landing elevation later, both trades resubmit. The architect returns the stairs 'approved as noted' in week 9, and fabrication takes another seven weeks. If the conflict had been found in the field, the fix would have meant cutting and re-welding steel on site, or relocating a sprinkler main after it was charged.

Who is responsible for errors

This is the most common shop drawing dispute. Design review is not a blanket blessing. Under FAR 52.236-21, approval by the contracting officer does not relieve the contractor of responsibility for errors or omissions in the shop drawings, or of the duty to meet contract requirements, except for variations the contractor specifically describes and gets approved. Work done before approval is at the contractor's risk. Private contracts often say similar things. The practical takeaway: if your shop drawing deviates from the contract, call it out clearly, in writing, on the submittal.

Common shop drawing mistakes

  • Submitting late, so long-lead fabrication pushes the schedule. Track them on a submittal schedule.
  • Passing sub drawings to the architect without a real GC review.
  • Burying a substitution or deviation in the drawings without flagging it.
  • Fabricating from drawings marked 'revise and resubmit.'
  • Not distributing approved drawings to the field and to related trades.

Related terms

Shop drawings are tracked in the submittal log, often trigger a request for information, and feed the long-lead items list and fabrication schedule. Read how to manage submittals on a construction project. Smart Business Automator tracks every submittal's status and due date across jobs.

Frequently asked questions

Who prepares shop drawings?

Usually the subcontractor, fabricator, or supplier responsible for that part of the work. The general contractor reviews and submits them.

Are shop drawings part of the contract documents?

Generally no. They are submittals that show how the contractor proposes to meet the contract documents. Check your contract, since it controls.

What is the difference between shop drawings and as-built drawings?

Shop drawings are prepared before fabrication to show how something will be made. As-built drawings are prepared at the end to show what was actually installed.

Does architect approval of shop drawings shift responsibility?

Typically not for errors in the drawings or for meeting the contract, unless a deviation was specifically called out and approved. FAR 52.236-21 states this for federal work.

Sources

  1. Acquisition.gov: FAR 52.236-21 Specifications and Drawings for Construction
Written and edited by

Maurice Francois writes and edits construction operations guides for Smart Business Automator. More from Maurice on the Scaling Legends podcast.

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