How to Cut Concrete Cores

How to Cut Concrete Cores thumbnail
You can use a core bit to create core holes in concrete.

All concrete walls such as foundations and retaining walls will need to have holes drilled through them to provide room for the drainage pipes as well as inlets for the gas lines or the HVAC lines or fiber-optic cables. The only way to drill through concrete is to use a core drill, which is basically a round drill bit with a special diamond or carbide tip on the end that cores through the concrete. They come in wet or dry formats, meaning they can cut wet or dry, but the principles are the same for both methods.

Things You'll Need

  • Safety glasses
  • Respirator
  • Work gloves
  • Ear plugs
  • Tape measure
  • Marker
  • Core drill
  • Proper sized drill bit
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    • 1

      Decide where you need to cut your core hole through the concrete and mark the center of the hole. Use a tape measure and pencil to mark the starting area. This is where the pilot bit for the core drill bit will penetrate the surface of the concrete, guiding the rest of the core bit through the concrete structure as you drill.

    • 2

      Attach the core drill bit to your core drill. This is exactly the same as any other normal drill. Loosen the head of the drill until the opening expands, then place the bit into the mouth of the drill. Tighten it using the included tool, which varies depending on the model of core drill you are using.

    • 3

      Hold the drill up in place and press the pilot bit -- a singular drill bit that is centered within the hollow section of the core bit, with the outer diameter of the core making up the actual diameter of the hole -- against your mark. Pull the trigger gently and apply pressure until the pilot bit is sunk into the concrete. After this happens, pull the trigger all the way and keep pressure on the drill while you core your way through the concrete.

Tips & Warnings

  • Cut on the outside of the building if possible, as the excessive dust from dry-coring and water from wet-coring will create a mess. You can rent a core drill and bits from your local home improvement store, although commercial versions for projects such as boring through 3-foot thick concrete are only available to licensed professionals.

  • Wear safety gear when working with power tools.

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  • Photo Credit Jupiterimages/Goodshoot/Getty Images

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