Cutting a hole in a tile for a pipe or tap is one of the trickier parts of a tiling job, but with the right tools and a bit of patience you can get a clean, professional result. The key is to mark carefully, work slowly, and choose the correct cutting method for your tile type.
Tools and Materials You'll Need
Before you start, gather the following:
- Diamond hole saw (most common and recommended for round holes)
- Angle grinder with a diamond blade (for larger or irregular cutouts)
- Tile drill bit (carbide or diamond-tipped, for pilot holes)
- Marker or chinagraph pencil
- Masking tape (helps prevent the drill from wandering)
- Water or a damp sponge (for cooling the bit)
- Safety glasses, hearing protection, and a dust mask — tile dust contains silica, which is a serious health hazard. Check WorkSafe NZ guidelines on working safely with silica dust.
- A spare tile or two for practice
Choosing the Right Method
The best approach depends on the size and shape of the hole:
| Hole Type | Best Tool |
|---|---|
| Small round hole (pipe, 20–50 mm) | Diamond hole saw |
| Large round hole (tap body, 50–100 mm) | Large diamond hole saw or angle grinder |
| Irregular/partial cutout (tap plate) | Angle grinder with diamond blade |
| Very small pilot hole | Carbide or diamond tile drill bit |
For most pipe and tap situations in NZ bathrooms and kitchens, a diamond hole saw attached to a standard power drill is the go-to choice.
Step-by-Step: Cutting a Round Hole with a Diamond Hole Saw
1. Mark the Centre Point
Measure carefully and mark the centre of the hole on the tile face with a marker. Apply a small piece of masking tape over the mark — this stops the drill bit skating across the glazed surface when you start.
2. Select the Right Hole Saw Size
Match the hole saw diameter to the pipe or fitting. Common pipe sizes in NZ are 15 mm and 20 mm copper or PEX, but always measure the outside diameter of the pipe or escutcheon plate to confirm. Most tap escutcheons will cover a hole of around 35–50 mm, giving you a little wiggle room.
3. Start the Hole at an Angle
Begin drilling at roughly a 45-degree angle to create a small groove that guides the saw into position. Once you have a starter groove, bring the drill upright to vertical and continue drilling straight through. Keep the drill speed moderate — high speed generates heat that can crack the tile or burn out the bit.
4. Keep It Cool
Heat is the enemy. Have a helper dribble water onto the cutting area continuously, or use a damp sponge. Some hole saws have a water feed; use it if yours does. Never dry-cut porcelain or ceramic tiles — you risk cracking the tile and shortening the life of your bit significantly.
5. Apply Steady, Light Pressure
Let the diamond grit do the work. Forcing the drill causes cracking and bit wear. Ease off pressure as you break through the back of the tile to avoid chipping the exit edge.
6. Clean Up the Edge
Once the hole is cut, smooth any rough edges with a tile file or diamond hand pad. In most cases the pipe escutcheon or tap cover plate will hide the edge entirely, but it's good practice to tidy it up.
Cutting Holes in Already-Fixed Tiles
If the tile is already on the wall, the process is the same but you need to be more careful:
- Support the tile — don't lean hard on the drill or you risk cracking the tile or dislodging it from the substrate.
- Be aware of what's behind the wall. If you're drilling near plumbing, stop before you break through fully and check the depth. You don't want to drill into a live water pipe. If in doubt, use a pipe/cable detector first.
- Porcelain tiles (common in modern NZ bathrooms) are much harder than standard ceramic — use a quality diamond hole saw rated for porcelain and expect it to take longer.
Cutting Irregular Shapes with an Angle Grinder
For tap plates or larger cutouts that aren't perfectly round:
- Mark the outline clearly on the tile.
- Use a diamond blade on an angle grinder to make straight cuts into the waste area, then carefully nibble away the material.
- Work slowly and keep the blade moving — don't let it sit in one spot.
- Always clamp the tile securely before cutting.
Angle grinders produce a lot of fine silica dust. Always wear a P2 respirator, safety glasses, and hearing protection. Work outdoors or in a well-ventilated area where possible.
A Note on Plumbing and Electrical Work
Cutting the tile itself is DIY-friendly, but connecting or moving the pipes and fittings behind the wall is a different matter. In New Zealand, plumbing work is restricted work under the Plumbers, Gasfitters and Drainlayers Act. Any work on water supply pipes, waste pipes, or gas fittings must be carried out by a licensed tradesperson registered with the Plumbers Gasfitters & Drainlayers Board. Similarly, any electrical work behind the wall must be done by a registered electrician — see the Electrical Workers Registration Board for details.
When to Call a Professional
Consider calling a qualified tiler if:
- You're working with large-format or expensive porcelain tiles where a mistake is costly.
- The hole position is complex or very close to a tile edge (high risk of cracking).
- You don't have access to the right tools.
- The job involves moving or modifying the plumbing itself.
A skilled tiler will have the right diamond tooling and experience to get a clean result first time. You can find qualified local tilers on tradedirectory.co.nz.
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