The $10,000 Eraser: Calculating the Real Cost of Preconstruction Catches

Everyone in construction knows that catching errors early is better than catching them late. It's obvious. But when you're justifying the cost of a new tool or an additional preconstruction review cycle, "better" isn't enough. You need numbers.

So let's put real numbers on it.

The 1-10-100 Rule

There's an old axiom in construction that goes like this:

The exact ratios vary by project, but the principle is consistent: errors compound. A missing dimension costs almost nothing to add to a CAD file. The same missing dimension, discovered when the framer is standing there waiting for an answer, costs an RFI cycle plus idle labor. Discovered after the framing is complete? Now you're looking at rework.

The 1-10-100 rule is actually conservative. Some studies put the field multiplier at 150x or higher for certain types of errors.

Hard Clashes vs. Soft Clashes

When people think about coordination issues, they usually think about hard clashes—the duct that runs through a beam, the pipe that conflicts with a column. These are dramatic. They're also, paradoxically, easier to catch. BIM software excels at finding them. They're visually obvious when you federate models.

The bigger cost driver? Soft clashes. These are the issues that don't involve physical overlap but still require rework:

These soft clashes are harder to find because they require reading and understanding the documents, not just overlaying 3D models. They're also responsible for a disproportionate share of RFIs and change orders.

The Math: A Single Missed Conflict

Let's walk through a realistic scenario. This is a composite of actual project data, not a hypothetical.

That's one conflict. One. On a typical commercial project, preconstruction review might catch 20-50 issues that, if missed, would have similar or greater impact.

The ROI Calculation

Now let's compare the cost of catching issues in preconstruction versus the cost of missing them.

This is a conservative calculation. It doesn't include:

• Schedule acceleration costs when multiple issues compound
• Relationship damage with owners and architects from repeated RFIs
• The time your PMs and engineers save on manual review
• Reduced exposure to claims and disputes

The Compound Effect

Here's what the ROI calculation misses: issues don't occur in isolation. One missed conflict can cascade.

Consider: The plumbing reroute from our example might push the waste stack into a different wall cavity. That cavity might have been sized for a 2" pipe, not 4". Now the drywall framing has to change. The electrical boxes in that wall have to move. The finish schedule for the adjacent room might shift because the wall thickness changed.

One issue becomes three. Three becomes eight. The $5,700 problem becomes a $25,000 problem—and it all started with a conflict that was visible in the drawings, if someone had looked.

Why "We Already Review Drawings" Isn't Enough

Every GC reviews drawings before construction. The question isn't whether you review—it's how thoroughly, and how consistently.

Manual review has limits:

Automation doesn't replace human judgment. It extends human attention. It ensures that every sheet gets the same level of scrutiny, every time, regardless of schedule pressure or fatigue.

Making the Business Case

When you're pitching preconstruction tools to leadership, focus on these numbers:

If you can prevent one $50,000 change order per year—just one—you've paid for the tool many times over. Most teams find dozens of issues per project.