Is it hard to drill porcelain tiles?

Quick answer - Is it hard to drill porcelain tiles?

It is only difficult if you use the wrong tools and technique. With a diamond tile bit or diamond hole saw, a drill in rotary mode at low speed, light pressure, and continuous water cooling, drilling porcelain is straightforward for most DIYers.

Use a diamond-tipped bit, keep the drill on rotary only, run at low RPM, cool the cut with water at all times, stabilise the start so the bit does not wander, and finish the hole gently to avoid chipping.

Why porcelain feels “hard” to drill

Material density and vitrification

Porcelain is fired hotter than ordinary ceramic, which vitrifies the body and makes it dense and glass-like. The density resists cutting by conventional masonry bits, so an abrasive diamond edge is needed.

Surface glaze and slip

The glossy glaze is slippery and encourages the bit to skate. A controlled start with tape, a guide, or a slight starting angle is essential to key the bit before drilling upright.

Heat build-up and micro-cracking risks

Friction generates heat quickly. Excess heat burns bits, chips the glaze, and can create micro-cracks. Cooling with water and pausing frequently prevents damage.

Tools and materials you’ll actually need

Drill types

Any good cordless or corded drill works provided it offers low speed and rotary mode. Do not use hammer action on porcelain.

Bits

Choose electroplated diamond tile bits for small holes and diamond hole saws for larger openings. Carbide may scrape through softer ceramics but is unreliable on porcelain.

Cooling setups

A spray bottle, a putty dam that holds a puddle of water, or a guide with a water feed will keep the cut cool and clear of slurry.

Marking kit

Masking tape, a wax pencil, and, if available, a suction drill guide or simple timber jig help you place the hole accurately.

PPE

Wear safety goggles and gloves, and use a dust mask. Keep electrics clear of any cooling water.

Preparation: marking and stabilising the start

Locate services behind the tile

Scan the area for pipes and cables before you mark up. Bathrooms often conceal services close to the tile face.

Choose the spot: grout line vs tile body

The tile body usually gives a cleaner, stronger hole. Grout can crumble and is rarely aligned with what you need behind the tile.

Prevent bit wander

Cross two short strips of masking tape over the mark, use a guide where possible, or start at a slight angle to create a bite, then bring the drill upright once the bit has keyed.

Core technique for small pilot holes (6–8 mm)

RPM and pressure

Run the drill slowly and let the diamond cut. Use light, steady pressure rather than force.

Wetting the cut

Keep the drilling point wet throughout. Work in short pulses and flush the slurry so the bit stays cool and sharp.

Breakthrough control

Ease off as you approach the back of the tile. Support fragile substrates where accessible and complete the final millimetres with minimal pressure to avoid spalling.

Stepping up to medium and larger holes

Step-drilling strategy

Open with a 6 mm pilot, then enlarge to 8 mm and finally to the required size. Staging keeps the cut true and reduces heat.

Using diamond hole saws (20–68 mm)

Use a guide plate or a plywood template, build a small water dam, and cut at low speed with frequent lift-offs to clear debris and cool the rim.

Plumbing penetrations

Measure so the escutcheon will cover the hole while leaving tolerance for movement. Keep to safe distances from edges to prevent cracks.

What not to do

No hammer action on porcelain

Impact chips the glaze and invites cracking. Keep the drill on rotary mode only.

Don’t run hot or dry

High speed or dry cutting overheats the tile and destroys the bit. Water cooling is non-negotiable.

Don’t force the bit or rush the breakthrough

If progress slows, back off, cool, and resume. Forcing the cut is what causes chips and fractures.

Drilling near edges, corners, and cut-outs

Safe distances from edges

Keep at least 20 to 25 mm from a tile edge, and more on thin or brittle tiles. Avoid holes across cut lines or notches.

Supporting large-format tiles

If the tile is loose or oversized, rest it on foam or cardboard with a backing board to absorb vibration while you drill.

Bathroom-specific best practice

Sealing the hole

After fixing, run a neat bead of sanitary silicone under flanges and around penetrations to block water ingress.

Load considerations

Distribute weight across multiple fixings, tie into studs where you can, and consider a hidden timber batten during refurbishment for heavy items.

Hygiene and cleaning of slurry after wet drilling

Wipe away slurry immediately so it does not stain grout. Rinse the area once drilling is complete.

Special cases and materials

Glazed vs unglazed porcelain

Unglazed porcelain starts more easily but still needs diamond tooling and water cooling. Glazed tiles demand extra care to avoid skating.

Textured or anti-slip surfaces

Textured faces help the start, yet the dense body remains the same, so technique and cooling still matter.

Porcelain slabs and sintered stone

Ultra-compact surfaces require top-quality diamond tools, strict speed control, and generous cooling. Keep holes well away from edges and corners.

Troubleshooting: chips, cracks, and stuck bits

If the glaze chips

A slight rim chip can often be hidden by the fitting. A very light countersink with plenty of water can tidy the edge if needed.

If a hairline crack appears

Stop immediately, dry the area, and reassess the load. Relocate the fixing or replace the tile rather than risking failure.

If the bit burns out or binds

Heat and debris are the causes. Withdraw the bit, cool it, flush the hole, and continue at a lower speed with lighter pressure. Replace worn tools promptly.

FAQs

Can I use a normal masonry bit?

It is not recommended. Masonry bits rely on a crushing action that works on brick or block but performs poorly on dense, vitrified porcelain. They skate on the glaze and overheat quickly. A diamond-tipped tile bit or diamond hole saw uses an abrasive cut that stays cool and clean with water, which is why it is the correct choice.

Do I really need water?

Yes, for porcelain you do. Water controls heat, clears slurry, and protects the glaze from thermal shock. You can mist from a spray bottle, drip from a sponge, or hold a small puddle in place with a putty dam. Cutting dry is slower, wears tools rapidly, and raises the risk of chipping.

What RPM should I use?

Keep it slow. As a rule of thumb, run most cordless drills at their lowest speed setting. For small diamond bits up to about 8 mm, aim around a few hundred RPM; for larger diamond hole saws, go slower still. The correct speed is the one that produces steady progress without heat build-up. If the water sizzles or the bit discolours, you are too fast.

How close can I drill to a tile edge?

Give yourself at least 20 to 25 mm from any edge, and more on thin tiles or near cut-outs. Edges are where cracks start, so support the tile well, keep the bit cool, and approach the breakthrough gently. If you must work closer, consider moving the fixing position or using a bracket with a wider footprint.

Is carbide good enough for one or two holes?

Sometimes, on softer ceramics, but porcelain is far less forgiving. Carbide spear bits dull quickly and often chip the glaze. A single good-quality diamond bit costs a little more but usually saves time, reduces risk, and leaves a neater hole.

How do I drill a 40–50 mm hole for a mixer outlet?

Use a diamond hole saw in the exact size, guided by a suction plate or a plywood template. Start with a small pilot to stabilise the position, build a putty dam to hold water, and cut at low speed with frequent lift-offs to flush slurry. Keep well away from tile edges and check that the escutcheon will cover the cut with a few millimetres of tolerance.