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How to review shop drawings

A systematic approach to shop drawing review that catches errors before fabrication.

Shop drawings bridge the gap between design intent and actual fabrication. A thorough review process protects the project from costly field corrections and ensures the finished product matches the design. Here's how to review shop drawings effectively.

What Are Shop Drawings?

Shop drawings are detailed drawings prepared by contractors, subcontractors, suppliers, or manufacturers. They show:

  • Exact dimensions for fabrication
  • Material specifications and grades
  • Connection details and hardware
  • Finishes and coatings
  • Fabrication and erection sequences
Common Shop Drawing Types
• Structural steel
• Precast concrete
• Curtain wall
• Millwork/casework
• HVAC ductwork
• Fire protection
• Electrical panels
• Elevator equipment
• Kitchen equipment

Step 1: Verify Submittal Completeness

Before diving into details, confirm the submittal package is complete:

  • All sheets included per the submittal log
  • Correct revision number and date
  • Project name and number clearly marked
  • Specification section referenced
  • Contractor's review stamp present
  • Product data sheets attached if required

Step 2: Check Dimensions Against Contract Documents

This is where most errors hide. Verify:

Overall Dimensions
  • • Total width, height, depth
  • • Opening sizes match plans
  • • Clearances to adjacent work
Component Dimensions
  • • Member sizes match specs
  • • Spacing and layout correct
  • • Hole locations and sizes
Critical check

Look for dimensions that require field verification. If the shop drawing says "verify in field," ensure this is acceptable or request actual dimensions.

Step 3: Verify Materials and Finishes

Confirm materials match the specifications:

  • Material grade, ASTM A36 vs A992, etc.
  • Finish type, Paint system, galvanizing, anodizing
  • Color, Matches spec color code
  • Thickness/gauge, Sheet metal, glass, panels
  • Fire rating, Where applicable

Step 4: Review Connections and Hardware

Connections are where failures happen. Check:

For Structural Steel

Bolt sizes and grades, weld symbols and sizes, connection type matches structural drawings, embed plate sizes and anchor patterns

For Architectural Elements

Anchor types and spacing, sealant joints and backing, thermal breaks, drainage provisions, movement accommodation

Step 5: Check Coordination with Other Trades

Shop drawings often reveal coordination conflicts:

  • Does the steel framing clear the ductwork?
  • Are electrical rough-in locations coordinated?
  • Do penetrations align with structural openings?
  • Is there clearance for maintenance access?

Understanding Approval Stamps

Approved

Proceed with fabrication. No changes required.

Approved as noted

Proceed with fabrication incorporating marked corrections. No resubmittal needed.

Revise and resubmit

Do not proceed. Corrections required before fabrication. Resubmit for review.

Rejected

Fundamental problems exist. Complete redesign may be required. Resubmit.

Common Shop Drawing Errors

Dimensions don't add up

Fix: String dimensions and verify totals

Wrong material specified

Fix: Cross-reference specification sections

Missing fire rating labels

Fix: Verify all rated assemblies are labeled

Inconsistent scale

Fix: Check scale bar and verify dimensions

Old revision of contract drawings used

Fix: Confirm current revision referenced

Deviations not highlighted

Fix: Require explicit deviation lists

Keep exploring

Related guides for submittal review and coordination.

Construction Punch List Best Practices

Create and manage punch lists efficiently.

Construction Change Order Guide

Understanding COs, CCDs, and PCOs.

How to Run an OAC Meeting

Best practices for coordination meetings.

How to Organize Submittals

Create a submittal management system.

Automate your shop drawing coordination

Manually cross-checking shop drawings against contract documents takes hours. Helonic's AI can flag dimensional conflicts, material discrepancies, and coordination issues automatically.