Shop Drawings vs. As-Built Models: Why Getting Both Right Is Critical for AEC Success

Last month, we watched a steel fabricator halt production on a $3.2 million healthcare project. The culprit? Shop drawings that looked perfect on paper failed to account for a 4-inch coordination conflict with the fire suppression system. Three weeks of delays, emergency redesign, and a very unhappy general contractor followed.

This is not an isolated incident. In our 15 years working with AEC teams, we have seen how the distinction between shop drawings and as-built models—two fundamentally different but equally critical deliverables—continues to trip up even experienced project teams.

The stakes have never been higher. With BIM coordination at LOD 400 becoming standard, digital twin requirements being written into contracts, and fabrication tolerances tightening to accommodate complex MEP systems, there is no room for ambiguity in documentation.

The Evolution of Construction Documentation

The architectural, engineering, and construction industry has moved far beyond the days of hand-marked redlines and rolled drawings, which were often pleated away in project trailers. Today’s projects demand BIM-native workflows, reality capture integration, and documentation that serves both immediate construction needs and 30-year facility management cycles.

However, this evolution has created new complexities. When a mechanical contractor submits shop drawings in Revit 2024, they are not just showing how they will install ductwork—they are building a data-rich model that feeds clash detection, coordinates with structural steel down to the bolt level, and eventually becomes part of the owner’s digital asset portfolio.

The problem? Many teams still treat shop drawings and as-built models as interchangeable documentation steps. They are not.

Shop Drawings: The Bridge Between Design Intent and Fabrication Reality

Shop drawings represent the contractor’s interpretation of design intent, translated into buildable specifications. They are created by the people who have to make things work in the field.

Who Creates Them and When

Shop drawings typically emerge during the submittal phase, after design development, but before fabrication begins. An MEP contractor might spend 200-300 hours developing shop drawings for a complex hospital project, coordinating routing with structural penetrations, fire-stopping details, and seismic bracing requirements.

Steel fabricators often work from preliminary structural models at Level of Detail (LOD) 300, then develop their shop drawings to LOD 400, adding connection details, erection sequences, and field bolt specifications that were not included in the original design.

What Makes Shop Drawings Valuable

The best shop drawings solve problems before they reach the field. They include:

• Dimensional coordination: Not just “Where does this pipe go,” but “How does this pipe clear the W24x68 beam while maintaining a 7′-6″ clear height for ceiling installation?”
• Installation sequences: Critical for prefab assemblies where installation order affects accessibility
• Material specifications: Down to the manufacturer part numbers, significant for specialized systems like clean rooms or data centers
• Interface details: How one trade’s work connects with another’s—the zone where most coordination failures occur

The Cost of Getting Shop Drawings Wrong

Poor shop drawings do not just delay projects—they multiply costs. We have tracked projects where inadequate shop drawings led to:

• 15-20% increases in fabrication costs due to field modifications
• 3-4 week delays while new materials are sourced
• Change orders averaging $50,000-$75,000 for mechanical systems alone.

As-Built Models: Capturing Construction Reality

As-built models document what got built, not what was planned. In an ideal world, these would match the approved shop drawings exactly. In reality, field conditions, RFIs, and last-minute changes often result in significant deviations from the original plan.

Why As-Builts Matter More Than Ever

Modern facility management depends on accurate as-built data. When a hospital needs to retrofit its HVAC system five years after construction, the facilities team must know precisely where every pipe, duct, and conduit runs, including all the field changes that occurred during the construction process.

The financial impact is substantial. Facility managers report that accurate as-built models reduce renovation planning time by 40-50% and eliminate costly investigative work, which can run $15,000 to $25,000 per project just to locate existing utilities.

The Reality Capture Revolution

Point cloud scanning has revolutionized the creation of as-built models. Using tools like the Leica RTC360 or Trimble X7, we can capture a 50,000-square-foot facility in 2-3 days and then utilize software like Autodesk ReCap to generate BIM models with an accuracy of within 3 mm.

But technology is not everything. The key is knowing what level of detail matters. For a warehouse renovation, capturing structural members and major utilities at Level of Detail (LOD) 350 may be sufficient. For a pharmaceutical facility, you need LOD 500 details on all process systems, including instrument air, clean steam, and WFI distribution.

Key Distinctions That Matter

Where Documentation Failures Hurt Most

Clash Detection and Coordination

Shop drawings drive the clash detection process, which has become a standard in BIM workflows. When a structural steel fabricator submits drawings that show beam connections conflicting with ductwork, that is a $5,000 problem. When the same conflict is not caught until field installation, it becomes a $50,000 problem involving crane time, rework, and schedule delays.

We use Navisworks Manage 2024 for federation and clash detection, but the quality of the underlying shop drawings determines whether we catch real problems or spend time resolving false positives.

Digital Twin Integration

As-built models increasingly feed directly into digital twin platforms. For a recent mixed-use development, the owner required as-built models compatible with their Bentley iTwin platform. This meant maintaining specific naming conventions, parameter structures, and geometric accuracy standards that weren’t negotiable.

The payoff is substantial. Buildings with accurate digital twins report 20-30% reductions in maintenance costs and significantly faster emergency response times when systems fail.

Regulatory Compliance and Commissioning

In healthcare and life sciences projects, accurate documentation is not just helpful—it is required. FDA validation protocols require as-built drawings that accurately match the installed conditions. We have seen projects where minor discrepancies between shop drawings and actual installation triggered expensive re-commissioning cycles.

The Uppteam Approach: Precision Through Process

Our methodology addresses the common failure points we have observed across hundreds of projects.

Shop Drawing Development

We do not just create shop drawings—we coordinate them. Our process includes:

• Multi-trade coordination sessions using Revit 2024 and Navisworks, where MEP, structural, and architectural teams work through conflicts in real-time
• Constructability reviews with field superintendents who’ve built similar systems
• Submittal preparation that anticipates common reviewer concerns and includes supporting calculations

For a recent data center project, our coordination process identified 47 conflicts before shop drawings were submitted, eliminating what typically becomes weeks of RFI cycles.

As-Built Model Creation

Our as-built workflow combines reality capture with intelligent modeling:

• Strategic scanning that captures critical areas at appropriate detail levels
• Model authoring that maintains BIM standards while reflecting actual conditions
• Quality verification through field checks and cross-referencing with approved shop drawings

We recently completed as-built modeling for a 250,000-square-foot pharmaceutical facility using a combination of laser scanning and conventional survey techniques. The resulting model enabled the owner to plan a $2 million clean room expansion without any investigative demolition.

Quality Assurance That Matters

Documentation quality is not just about accuracy—it is about usability. Our QA process includes:

• Coordination verification using automated clash detection and manual review
• Standard compliance, ensuring models meet client CAD standards and industry best practices
• Deliverable testing is where we verify that models work correctly in the owner’s downstream systems

The Bottom Line

Shop drawings and as-built models serve different purposes, but both are essential for project success. Shop drawings enable precise fabrication and field coordination. As-built models provide the accurate baseline that modern facility management demands.

The companies that understand this distinction—and invest in getting both right—consistently deliver projects on time, within budget, and ready for decades of efficient operation; those who do not find themselves managing expensive problems that could have been prevented with better documentation discipline.

At Uppteam, we have built our reputation on delivering documentation that works, not just for today’s construction needs but for the entire building lifecycle. Because in an industry where a single coordination failure can derail a project, precision is not just a matter of professional pride—it is a matter of business survival.