What core drilling costs — and why

Core drilling has one of the most predictable pricing structures in construction — once you know the variables. This guide explains the model so the first quote you receive makes sense, and so you can spot both a padded number and a too-good-to-be-true one.

The basic pricing model

Almost every operator prices cores the same way:

Price = mobilization minimum + (per-hole rate × holes), where the per-hole rate scales with diameter and depth.

• Diameter sets the rate class. A 2 in core and an 8 in core through the same slab are different prices because bit cost, drilling time, and handling all scale with size. Many estimators think in per-inch-of-diameter terms per inch of depth.
• Depth multiplies it. A hole through a 6 in slab-on-grade costs less than the same diameter through a 12 in elevated deck, and far less than a 3 ft foundation wall requiring barrel extensions.
• Mobilization minimum is the floor. Bringing a rig, an operator, water handling, and power to a jobsite costs the same whether one hole gets drilled or thirty — so one-hole jobs carry a minimum that can exceed the drilling itself. As a rough national reference, small jobs commonly land in the low-to-mid hundreds of dollars even when the drilling itself is minutes of work; actual Miami pricing is set by the provider who reviews your scope.

The multipliers estimators apply

These site factors move a quote meaningfully in either direction:

• Orientation. Vertical-down holes are the baseline. Horizontal work needs the rig anchored to the wall; overhead drilling is the slowest and most demanding setup.
• Access. A ground-floor garage next to parking is cheap. The 14th floor via a shared freight elevator, 300 ft from the closest staging, is not.
• Occupancy. Occupied space means containment, protection, and slower work — see slurry control for what that involves below an occupied unit.
• Scanning. On elevated decks, GPR scanning is a line item you want, not a cost to dodge — a cut tendon costs more than any scan program.
• Night or weekend windows. Night work carries a premium for the shift, security coordination, and shorter effective hours.
• Dry drilling. Where water is prohibited, dry methods run slower and eat bits faster — the rate reflects it.
• Heavy reinforcement. Cutting steel is normal, but a congested heavily reinforced element slows penetration rates and shows up in the price of large-diameter work.

Why hole count is your friend

The mobilization minimum amortizes. Ten holes drilled in one visit price dramatically better per hole than ten holes across five visits. The practical implications:

1. Batch the scope. If plumbing needs six cores this week and electrical needs eight next week, one coordinated mobilization beats two.
2. Finalize layout before the rig arrives. Re-mobilizing because two holes moved is the most avoidable cost in coring.
3. Combine methods. Cores plus a saw-cut trench or a wall opening in one visit shares the mobilization.

What a priceable request looks like

An estimator can commit to a number when they know:

• hole quantity and diameters (grouped: “12 × 4 in, 3 × 8 in”)
• element and thickness (“8 in elevated PT deck” vs “unknown, 1970s condo”)
• orientation, floor level, and access route
• GPR status: done / needed / not sure
• water and power availability
• day or night window

That is exactly what the request form asks. Requests that arrive with a penetration schedule or marked-up plan routinely get priced without a site visit; vague ones get a range and a walk-through first — which is the estimator protecting both of you, not stalling.

Red flags in cheap quotes

A number far below the others usually means one of: no scanning where scanning is due, slurry left as someone else’s problem, debris and core disposal excluded, or a mobilization that will “adjust” once the crew sees the site. Ask what is excluded before comparing totals — the quote requirements guide has a full checklist.