Best Practices9 min read

Iterative Design QA: Checking at SD, DD, and CD Milestones

The best time to catch a design error is as early as possible. Instead of waiting until permit submission, run AI checks at each design milestone. Issues caught at SD cost a fraction of what they cost at CD—or worse, during construction.

Published: December 29, 2025By InspectMind Team

The Cost of Late Discovery

Construction industry research consistently shows that the cost of fixing an error increases exponentially as a project progresses:

1x
Design
10x
Pre-Construction
100x
Construction
1000x
Post-Construction

An error that costs $1,000 to fix during design might cost $10,000 during pre-construction, $100,000 during construction, and $1,000,000+ in litigation after the project is complete. Early detection isn't just convenient—it's essential.

QA at Each Design Phase

SD

Schematic Design

30% Complete

What to Check

  • Program vs design alignment
  • Building code zoning compliance
  • Major systems feasibility
  • Egress path viability

Why It Matters

Catch fundamental design flaws before significant effort is invested. Changes at SD cost 10x less than at CD.

DD

Design Development

60% Complete

What to Check

  • Cross-discipline coordination
  • Structural-architectural interface
  • MEP routing conflicts
  • Detail consistency

Why It Matters

Coordination issues emerge as disciplines develop their designs. Catching them now prevents major rework at CD.

CD

Construction Documents

100% Complete

What to Check

  • Spec vs drawing conflicts
  • Detail reference accuracy
  • Code compliance completeness
  • Constructability issues

Why It Matters

Final check before permit submission or bid. Issues caught here prevent plan check comments and RFIs.

The Compounding Problem

Design errors don't exist in isolation. A structural column that's in the wrong location at SD becomes:

  • An architectural layout problem (partitions can't align)
  • An MEP routing problem (ductwork can't fit)
  • A structural engineering problem (loads don't transfer)
  • A code compliance problem (egress widths are inadequate)

By the time you reach CD, that single column has created issues across four disciplines. Fixing it now requires rework from multiple teams. Had it been caught at SD, it would have been a simple revision on a single sheet.

How AI Enables Iterative QA

Traditional QA methods make iterative checking impractical. Manual review of a 200-sheet set takes days or weeks. You can't afford to do that at every milestone. AI changes the economics:

Fast Turnaround

AI reviews complete in hours, not days. You can run a check at each milestone without delaying the design schedule.

Consistent Coverage

Every page, every detail, every specification section is checked every time. No fatigue, no shortcuts, no missed areas.

Progress Tracking

Compare results across milestones. See which issues were resolved and which new issues emerged as the design developed.

Predictable Cost

With project-based pricing, run unlimited checks throughout design. No per-check fees discouraging early detection.

Implementing Iterative QA

Here's how to integrate AI checking into your existing design process:

  1. 1

    Establish Review Gates

    Add AI review as a formal step before each design milestone submission. SD check before SD presentation, DD check before DD sign-off, etc.

  2. 2

    Assign Issue Owners

    Route AI-found issues to the responsible discipline lead. Mechanical issues to the mechanical PM, structural to structural, etc.

  3. 3

    Track Resolution

    Mark issues as resolved in the system. The next milestone's review will verify that previous issues were actually addressed.

  4. 4

    Trend Analysis

    Review issue patterns across projects. Are certain issue types recurring? This informs design standards and training.

Ready to Catch Issues Earlier?

Start running AI checks at every design milestone. Prevent compounding errors and deliver higher quality documents.

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