How do I drill into tile without cracking it?

Breaking the glaze without cracking the tile, keeping the bit cool, and where to place the hole.

Difficulty: beginner
Time: 25 min
Read: 3 min
Safety: caution

Short answer

Hammer action off, masking tape over the spot, and start slowly at a shallow angle to break the glaze before bringing the drill upright. Keep the bit cool with water and let it cut rather than pushing.

Tiles crack because of percussion and heat. Remove both and drilling one is straightforward.

Safety

Hammer action cracks tiles — switch it off before starting. Check for pipes and cables behind the wall, since bathroom and kitchen tiling frequently hides both. Wear eye protection, as glaze fragments are sharp.

Step by step

Turn hammer action off.The single most important step. Percussion cracks glaze immediately and often splits the whole tile.
Check what is behind.Pipes and cables run behind bathroom and kitchen tiling constantly. Use a detector and think about where the shower and taps are fed from.
Mark and tape the spot.Two strips of masking tape crossed over the point. It stops the bit skating and gives you something to mark on.
Aim for the middle of a tile.Not the edge and not the grout line if you need a strong fixing. Drilling near an edge is what splits tiles.
Use the right bit.A spear-point tile bit for ceramic, a diamond bit for porcelain. Porcelain is much harder and an ordinary tile bit will not touch it.
Start at a shallow angle.Ease the bit in at an angle to score through the glaze, then bring the drill upright once it has bitten. Starting flat lets the tip wander.
Go slowly with light pressure.Low speed, let the bit cut. Pushing hard generates heat and heat is what cracks tiles and destroys bits.
Keep it cool.A damp sponge held below, or pause every few seconds. Diamond bits in particular need water or they glaze over and stop cutting.
Switch to a masonry bit once through.Once past the tile, change to a masonry bit and hammer action for the wall behind — but only after the tile is fully penetrated.
Use the right plug.The hole must be deep enough that the plug sits entirely in the wall behind, not in the tile or the adhesive bed. A plug expanding inside a tile cracks it.

Tips

Hammer off until you are through the tile, then hammer on for the wall behind.
Porcelain needs a diamond bit. An ordinary tile bit will simply polish it.
The plug must sit in the wall, not in the tile. Drill deep enough.

Common mistakes

Leaving hammer action on — The percussive blow shatters the glaze and frequently cracks the tile right across. Tile needs rotation only.
Letting the plug expand inside the tile — The expanding plug puts outward pressure on brittle ceramic and cracks it. Drill deep enough that the plug sits fully in the substrate.

If it doesn't work

Bit spinning without cutting

Cause: Wrong bit for porcelain, or bit glazed over — Fix: Use a diamond bit and keep it wet. Porcelain needs diamond, not a spear point.

Tile cracked

Cause: Hammer action, too close to an edge, or too much pressure — Fix: Not repairable. Replace the tile and start further from the edge with hammer off.

Bit skating

Cause: No tape and starting flat — Fix: Cross masking tape over the spot and start at a shallow angle.

Fixing loose after drilling

Cause: Plug not reaching solid wall — Fix: Drill deeper so the plug sits entirely in the wall behind the adhesive bed.

Questions people ask

Should I drill into the tile or the grout?

Into the tile if you need a strong fixing — grout is weaker and often has a void behind it. Grout is easier to make good later if the fixing is light.

How do I drill porcelain?

A diamond core or diamond tip bit, kept wet, at low speed. Standard spear-point tile bits do not cut porcelain.

Can I use a normal masonry bit?

For the wall behind, yes, once the tile is drilled through. Starting a masonry bit on the glaze usually cracks it.