Concrete coring isn't a one-size-fits-all job—the holes you need directly determine the equipment, cost, and timeline of your project. Whether you're running utilities, installing anchors, or creating access points, knowing what's actually achievable makes the difference between a smooth job and a costly mistake.
The Standard Range: What Most Coring Jobs Handle
Most concrete coring contractors work comfortably in the 1-inch to 24-inch diameter range. This covers the vast majority of residential and commercial applications—think HVAC ducts, plumbing, electrical conduit, and structural bolt installations. Within this range, you'll get competitive pricing and fast turnaround, typically 1–3 days depending on depth and concrete thickness.
Anything in the 4-inch to 12-inch range is considered standard work and usually carries the most predictable costs. Contractors have the right equipment on hand, material prices are stable, and they can move efficiently. If your project falls here, expect straightforward quotes with minimal surprises.
Going Smaller: 1-Inch to 3-Inch Holes
Small-diameter coring is fast and affordable, but it has limitations worth understanding. Holes under 3 inches work well for:
- Sensor installations
- Small utility lines
- Anchor bolts for light fixtures
- Cable runs
Expect to pay $40–$100 per hole in this size range, depending on depth and concrete strength. The downside: many contractors have minimum charges of $150–$300 per job, so coring two small holes often costs the same as ten. If you need multiple small holes, bundling them into one service call saves money.
These holes are quick—often drilled in minutes—but the concrete dust and mess don't shrink with hole size. You'll still need proper containment and cleanup.
Going Larger: 14-Inch to 24-Inch Holes
Large-diameter coring ($200–$600+ per hole) is common for major MEP (mechanical, electrical, plumbing) penetrations, large ductwork, or structural access. The equipment is heavier, drilling takes longer (30 minutes to 2+ hours per hole depending on depth), and the contractor needs more experience to avoid hitting rebar or prestressing cables.
At 18–24 inches, you're entering specialized territory. Not every contractor has the gear, and some may subcontract the work. Always verify equipment availability upfront; otherwise, you risk project delays.
Beyond 24 Inches: Specialty Work
Once you exceed 24 inches, you're typically looking at core drilling equipment rentals or specialized contractors who charge premium rates. Some can handle holes up to 48 inches or more, but these jobs require:
- Advanced scanning to locate rebar and post-tension cables
- Reinforced drilling rigs (heavier, slower)
- Extended timelines (full-day or multi-day jobs)
- Costs scaling to $800–$2,000+ per hole
For holes this large, you may also encounter cost-competitive alternatives like diamond wire cutting or saw cutting, depending on your geometry and precision needs.
Critical Factors That Affect Hole Size Options
Concrete strength matters enormously. A 4-inch hole in 30-year-old concrete with lightweight reinforcement takes 15 minutes; the same hole in modern 5,000-PSI concrete with heavy rebar can take three times longer and require equipment upgrades.
Depth affects pricing exponentially. A 4-inch hole at 6 inches deep costs far less than a 4-inch hole through 12 inches of concrete. Anything deeper than 12–14 inches often triggers additional charges.
Hidden obstacles—rebar, post-tension cables, HVAC ducts, or electrical conduit—can halt the job or require repositioning. Scanning with ground-penetrating radar (typically $200–$500) prevents expensive mistakes on critical projects.
Water and mess containment adds $100–$300 to most jobs. If you're drilling multiple holes or in occupied spaces, budget for dust suppression and slurry removal.
How to Get Accurate Quotes
Provide contractors with these specifics: exact hole diameter (or a range), depth, quantity, concrete type (post-tensioned, standard, lightweight), and whether scanning is needed. Vague requests lead to vague pricing. Mercoly lets you compare and find trusted concrete coring providers in one place, so you can see how different contractors approach the same project.
Request references for projects matching your hole size—a contractor experienced in 2-inch holes may be ill-equipped for your 16-inch specification.
Frequently Asked Questions
Q: Can contractors core a 30-inch hole through 18 inches of reinforced concrete? Yes, but it requires specialized equipment and may take a full day. Budget $1,500–$3,000 and confirm the contractor has experience with that size before booking.
Q: What's the smallest hole that's worth having a contractor do versus DIY? Anything under 2 inches is often a DIY job with a standard drill and a core bit ($20–$40), assuming the concrete isn't heavily reinforced. Above 3 inches, professional equipment becomes cost-effective and far cleaner.
Q: Will the contractor detect what's inside the concrete before drilling? Not automatically. Ground-penetrating radar scanning ($200–$500) is the best way to find rebar, cables, and utilities; it's essential for large holes or critical locations.
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