A core drilling machine can cut through a commercial slab in minutes, but it can't tell what's inside. One unmarked cable turns routine core drilling into a multi-day delay. The American Concrete Institute (2023) reports close to 30% of concrete drilling incidents involve unmarked utilities or rebar damage. For coordinators, scanning first is a schedule decision, not just a safety one.
What Does a Core Drilling Machine Do?
A core drilling machine uses a diamond-tipped bit to cut clean, round holes for pipes, conduits, and anchors. It cuts through rebar and cables as easily as plain concrete.
Why GPR Concrete Scanning Comes First
GPR concrete scanning sends radar into the slab and reads what bounces back. Rebar, cables, and voids each reflect differently, letting a technician mark hazards before the bit ever turns.
How It Works
- Technician scans the slab in a grid pattern
- Hazards are marked directly on the concrete
- Crew reviews the marks before setup
- Core drilling proceeds only in cleared zones
Mistakes to Avoid
Skipping the scan on "simple" slabs, scanning only the exact hole spot, and drilling before markings are reviewed are the top causes of avoidable damage.
Scan First vs Skip
| Approach | Risk | Best For |
|---|---|---|
| Scan, then core drilling | Low, hazards caught early | Every coring job |
| Core drilling without a scan | High, damage possible | Not recommended |
FAQ
Q1: What is a core drilling machine? It cuts clean, round holes in concrete using a diamond-tipped bit.
Q2: Why does GPR concrete scanning come before core drilling? It reveals rebar and cables the machine would otherwise cut through.
Q3: Is GPR concrete scanning safe on active sites? Yes, it uses low-power radar with no evacuation zone needed.
Q4: How long does a scan take? A typical slab section takes under an hour to scan.
Conclusion
A core drilling machine is only as safe as the information behind it. GPR concrete scanning first keeps schedules intact and prevents costly damage during core drilling. Making scanning a standard first step protects every project from avoidable setbacks.