Quick Answer: To core drill through tile and masonry, mark the center, start with a small pilot or a slow-speed starter pass, then run a diamond core bit wet at rated speed so it cuts the tile and the backing in one clean pass. Let the bit find its own edge and avoid rocking it, which breaks tiles.

Why Tile Is the Hard Part

Tile is hard, brittle, and unforgiving. The face chips or cracks when the bit wobbles, when the feed is too hard, or when it starts on a glazed surface without seating. The trick is to seat the bit gently first, then let it grind through the glaze before applying any real pressure.

If the bit is bigger than the tile and the backing is masonry, the same bit does both: tile first, then concrete block or brick underneath.

Starter Technique

1. Mark the center clearly and cover it with tape or a starter template to stop bit wander.
2. Start the drill at low speed and let the bit scribe a ring into the glaze.
3. Once the ring is cut, increase to rated speed and feed steadily.
4. Keep water or a spray bottle on the cut; dry cutting tiles risks thermal cracking.

A pilot drill with a small masonry bit through the tile first gives the core bit a guide hole and protects the face from slip.

Bit Selection

Use a diamond core bit with a continuous or segmented rim sized to the hole. For tile plus masonry, a wet-rated bit with a medium bond balances speed and edge quality. The diamond core drill range includes sizes from small plumbing holes up to large penetrations.

Finishing the Hole

Ease pressure in the last inch so the exit side of the masonry does not spall. After breakthrough, remove the core slug, clean the rim of the hole, and check the tile face for chips. Small face chips can be patched with tile adhesive if they are cosmetic, but prevention is the real goal: seat gently, stay true, keep it wet.

FAQ

Can I use a hammer drill on tile?

No. Hammer action shatters tile. Use a diamond core bit in a rotary drill with no hammer for the tile, then you may add hammer once through into masonry.

What speed should I core drill tile?

Start at low speed to seat the bit, then run at the bit's rated speed. Too fast on the glaze creates heat and chips.

Why does my hole come out chipped?

Rocking the bit, starting without a pilot, or feeding hard on the glaze are the usual causes. Seat gently and keep the drill perpendicular.

Conclusion

Seat the bit slowly, keep it perpendicular, and cut tile and masonry wet in one pass. With the right diamond core bit and a steady hand, you get a clean round hole without a cracked tile.