To drill holes larger than one inch in diameter, use a core-drilling bit. A core-drilling bit has an open centre or a centre arbor that allows the concrete to enter inside the bit. There are core-drill bits available that you can insert into a hammer drill rather than renting and securing a core-drill to the wall.
- Skill level:
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Things you need
- Core-drill bit sized for your pipe
- Hammer drill
- Safety glasses
- Ear protection
- Work gloves
- Hand pressurised water sprayer filled with water
Insert the core-drill bit into the hammer drill. Set the hammer drill on the rotary mode; you will not need the hammer option with the core bit.
Put on the safety glasses, ear protection and work gloves.
Pump the handle of the sprayer to pressure the water tank.
Set the tip of the core-drill bit against the concrete block wall. Have a helper continually spray water where the tip of the drill bit intersects the wall throughout the drilling process, pumping the handle as necessary to maintain water pressure.
Start drilling the hold while maintaining a firm grip on the hammer drill with both hands. (Larger diameter core-drill bits can grab strongly into concrete.)
Keep the drill bit turning after you bore through the wall to back out the bit. Hold the bit level--there will be a core of concrete within the bit.
Tilt the hammer drill toward the ground to remove the core from the bit.
Clean the core-drill bit and hole in the concrete block hole by spraying them with water.
Dispose of the concrete core that you removed from the core bit in Step 7.