How to drill bathroom porcelain tiles

A practical, step-by-step method for small fixing holes and larger openings, including how to anchor into the wall behind the tile so the result is strong and safe.

Tools and materials you will need

A variable-speed drill in rotary mode only, diamond tile bits for small holes, diamond hole saws for larger holes, a drill guide or masking tape, a spray bottle of water or a putty dam to hold a puddle over the drill point, suitable wall plugs or hollow-wall anchors for the substrate, stainless or galvanised screws, a cable and pipe detector, a pencil or wax marker, a spirit level, PPE such as goggles, gloves and a dust mask, and a bathroom grade silicone sealant.

Before you start

1. Scan the wall for services. Use a multi-detector to check for hidden cables and pipes. Bathrooms often hide supply lines close behind the tile face.

2. Choose the exact spot. The tile body is usually stronger than the grout. Keep holes at least 20 to 25 mm from tile edges.

3. Stabilise the drill start. Cross short strips of masking tape over the mark, or use a drill guide. Mark the centre clearly.

4. Plan the anchor into the substrate. The tile is only the face. In masonry, set the plug in the brick or concrete. In plasterboard, use a cavity anchor or fix into a stud.

Set the drill to rotary only at the lowest speed. Do not use hammer action on porcelain.

Method A: small fixing holes (6–8 mm)

Step 1: Wet the area. Spray the mark or form a small ring of putty and fill it with water so the bit stays cool.Step 2: Start the hole. Hold the drill a fraction off-square for a second to help the bit bite, then bring it upright as soon as it keys in. Keep pressure light and speed low.

Step 3: Keep it cool. Drill in short pulses and let water flush the slurry. If water steams or the bit darkens, slow down.

Step 4: Control the breakthrough. Ease off as you approach the back of the tile to prevent spalling.

 Step 5: Continue into the substrate. Change to the correct bit for the wall behind if needed. In masonry, switch to a masonry bit sized for the plug. In plasterboard, a toggle or metal cavity anchor may not need further drilling.

Method B: medium and large holes (valves, wastes, cable grommets)

Step 1: Pilot. Make a 6 mm pilot to guide the hole saw.

Step 2: Guide and water. Fit a suction guide or a plywood template. Build a putty dam to hold water around the cut.

Step 3: Cut slowly. Run the diamond hole saw at low speed with light, even pressure. Lift the saw every few seconds so fresh water cools the rim and clears swarf.

Step 4: Finish cleanly. Ease off at breakthrough. Check that the escutcheon or flange will cover the cut with a little tolerance.

Fixing into the wall behind the tile

Solid masonry behind the tile

Vacuum dust from the masonry section. Insert a quality plug so most of its length sits in brick or concrete, not in the void. Use stainless or galvanised screws. Tighten until firm, then stop. Over-tightening can crush the tile face.

Plasterboard or dot-and-dab

If possible, fix into studs using long wood screws. Locate studs with a finder. Where studs are not available, use high load cavity anchors such as spring toggles or metal expanding anchors rated for bathrooms. For heavier items, consider a timber batten fixed across several studs, then mount the cabinet or rail to the batten.

Mixed or uncertain substrates

If the build-up is unknown, drill a small test hole in a hidden spot. For significant loads, consider chemical anchors into masonry behind dot-and-dab, or install a concealed batten during refurbishment.

Sealing and finishing for bathroom conditions

Seal penetrations to keep water out of the wall. Apply a small bead of sanitary silicone in the hole mouth before inserting the fixing, then add a neat bead around the bracket or escutcheon. Wipe away drilling slurry promptly so it does not stain grout. For towel rails, cabinets, and shower screen brackets, spread load across multiple fixings and use nylon spacers or stand-offs so pressure goes to the substrate, not the tile face.

Safety checklist

Wear eye protection for every cut since porcelain fragments are sharp. Keep hands clear of the bit and hot swarf. Manage water so it cannot reach live electrics. Always scan for pipes and cables. Work slowly, allow cooling pauses, and keep the floor dry and clear.