Core drilling is often treated as a minor trade activity, but for drywall contractors, its downstream impact can be significant. When mechanical, electrical, or plumbing (MEP) systems require vertical or horizontal access through wall assemblies, core drilling becomes unavoidable—and so does the potential for drywall damage and costly rework. For architects, engineers, and general contractors, understanding how to plan for and mitigate the effects of core drilling is essential to maintaining cost and schedule control on commercial construction projects.

What is Core Drilling and Why Does It Matter to Drywall?

Core drilling involves cutting precise cylindrical holes through concrete, CMU, or drywall surfaces to allow MEP systems to pass through. While necessary, this process can affect drywall in multiple ways:

• Damage to adjacent finishes from vibration, dust, or tool access
• Tearing or cracking of fire-rated or sound-rated assemblies
• Compromised integrity of shaftwall or partition systems
• Unanticipated patching and re-taping labor

Each core hole that interacts with drywall introduces a potential risk for schedule delays, extra labor, and budget overruns. These costs often go undocumented in early estimating phases, leading to underbid scopes or contested change orders later.

How Estimators Can Account for Core Drilling Risk

While drywall is typically estimated by area and type, core drilling introduces a variable not reflected in basic square footage. Experienced estimators leverage tools like Active Estimating to flag zones where penetrations are likely and apply labor and patching factors to assemblies accordingly.

Best Practices for Estimating Core Drilling Impacts:

• Tag high-risk zones: Mechanical rooms, risers, and utility corridors should be isolated and adjusted for rework potential.
• Apply productivity multipliers: Use +15–30% labor assumptions in core zones, depending on wall type and MEP density.
• Break out patching scope: Treat drywall patching as a separate line item for pricing and tracking.
• Use model overlays: Leverage model-based tools to identify where drywall intersects with expected core paths.

Drywall Types Most Affected

Not all drywall systems respond to core drilling the same way. The following systems are particularly sensitive:

• Fire-rated walls (due to integrity testing and resealing requirements)
• Shaftwall systems (where core drilling from one side is impossible)
• Acoustical partitions (where sealant continuity may be compromised)
• Prefabricated drywall panels (which are difficult to modify in the field)

Estimators using modern drywall estimating software can apply dynamic rules based on assembly metadata, ensuring patching assumptions scale properly across different wall types.

Integrating Core Drilling Risks into the Schedule

Beyond cost, drywall rework due to core drilling can also affect sequencing:

• Reopened areas may delay taping and painting activities
• Post-core inspection requirements may hold up wall closures
• Additional mobilizations may be required for patch crews

By proactively identifying and estimating for these schedule impacts, general contractors can better align subcontractor timelines and reduce disruption.

Conclusion: Don’t Let Cores Drill Into Your Margins

Core drilling may be outside the drywall contractor’s scope, but its consequences fall squarely within it. Accurate drywall estimating requires more than measuring board—it requires anticipating the real-world conditions that lead to rework. With proper tools and assumptions, estimators can flag high-risk areas, assign realistic patching budgets, and provide clarity to project teams. In doing so, they protect both the budget and the schedule from one of the most common (and overlooked) drywall risk factors on complex jobs.

Contact Information:
Active Estimating
508 2nd Street, Suite 208
Davis
California
95616

Rich Schoener
richard@activeestimating.com
(877)