Drilling a hole in a tile you have just laid is nerve-wracking — one crack and the tile is scrap. The good news is that you can drill ceramic tile reliably with the right bit and a calm, cool technique.
Ceramic Versus Porcelain
Standard glazed ceramic and quarry tile are relatively soft under the glaze. Porcelain and glass are much harder and more brittle. A carbide-tipped tile or masonry bit handles softer ceramic, but for porcelain, glass and stone you really want a diamond-coated bit, which grinds through the hardest surfaces without shattering them.
Beating the Glaze
The slick, hard glaze is where bits skate and tiles chip. Stop the bit wandering by placing a strip of masking tape over your mark; it gives the tip a little grip and reduces surface chipping. Start at a low speed with light pressure to score through the glaze, then continue steadily once the bit has bitten in. Never use hammer mode — the percussion that helps in concrete will crack a tile.
- Diamond bits: the safe choice for porcelain, glass and stone.
- No hammer: keep the drill in rotary-only mode for all tile.
- Keep it cool: a little water stops heat building and preserves the bit.
Keep the Bit Cool
Heat is the fastest way to ruin both the tile and a diamond bit. Wet the drilling spot with a sponge, or dribble water as you go, and pause frequently to let things cool. A small dam of plumber putty around the hole can hold a puddle of water right where you need it. Keep the drill out of any splash zone for safety, and never let a diamond bit run dry for more than a moment. Water also flushes away the fine grinding slurry, which keeps the diamond grit cutting cleanly instead of clogging and glazing over.
Steady Technique
Let the bit do the cutting with light, consistent pressure — forcing it is what cracks tiles. On wall tile, work slowly through the glazed layer, then through the body of the tile. When you break through to the substrate behind, switch to an appropriate masonry bit for the wall material if you need to go deeper into brick or block.
Placement Matters
Keep holes away from tile edges and corners where the material is weakest; a hole too close to an edge is far more likely to split. If you must drill near a grout line, aim for the centre of the tile face instead when you can, since drilling through a grout joint often chips the surrounding tile edges. Mark carefully, support the tile fully against the wall or bench, and take your time. On a wall, remember there may be pipes or cables behind the tile, so check before you commit. Patience is the real trick.