Why a Regular Drill Bit Won't Work Here

Porcelain tile is one of the hardest finishing materials available. On the Mohs scale, its hardness is comparable to hardened steel, which means a standard metal or wood drill bit simply slides across the surface without making a mark. At best you waste time, at worst you end up with a chip or crack right in the middle of an already installed tile. Drilling porcelain tile is entirely possible — but only with the right tool and the correct technique.

What Tools Are Suitable for Drilling

The choice of tool depends on the hole diameter and the volume of work:

• Diamond Core Bits — the optimal choice for most tasks. The cutting edge is diamond-coated, which gradually grinds away the material without any impact action. Suitable for holes 20 mm and larger — for sockets, pipes, and faucets. Use only in non-impact drilling mode, always with water cooling.
• Diamond Drill Bits (Tubular) — used for smaller diameter holes. The principle is the same: diamond coating, no impact, with cooling. They perform well for precise holes for wall plugs and fasteners.
• Tungsten Carbide Tipped Bits (Pobedit) — acceptable for thin wall tiles, but poorly suited for porcelain stoneware. The material is too hard, causing the bit to dull quickly and increasing the risk of chipping. Use only as a last resort and at minimum speeds.
• Spear-Point Ceramic Bits — suitable for small holes in medium-hardness porcelain. They operate without impact at low speeds. Not recommended for large-format or high-strength porcelain stoneware.

Hammer Drill or Regular Drill: What to Choose

The answer here is clear: a regular drill only, and only in non-impact mode. A hammer drill creates percussive force that porcelain tile cannot withstand — the tile cracks, and the crack can travel sideways and damage neighbouring pieces. If you only have a hammer drill, switch it to pure drilling mode (no hammer). In this mode it works like a standard drill and is perfectly suitable for use with a diamond core bit or drill bit.

Cooling: There Is No Way Around It

Diamond tools heat up very quickly during drilling. Overheating destroys the coating — the core bit or drill bit wears out prematurely, and the tile can crack from thermal shock. Cooling methods:

• Water — the most effective method. For wall tiles, use a plasticine dam around the drilling point and fill it with water. For floor tiles, wet the drilling area and add water periodically during the process.
• Breaks — if water cooling is not possible, stop every 15–20 seconds to let the tool cool down.
• Special lubricants — available at hardware stores, they reduce friction and temperature at the contact zone.

How to Drill Porcelain Tile Correctly: Step by Step

1. Mark the drilling point. Apply masking tape — it prevents the bit from slipping at the start and protects the surface from scratches.
2. Start at minimum speed. A fast start at high speed is a direct route to chipping. Work slowly for the first few seconds until a small indent forms.
3. Keep the drill strictly perpendicular to the surface. Even a slight angle increases the load on the edge of the core bit and raises the risk of cracking.
4. Do not press hard on the tool. Diamond coating works through rotation, not pressure. Extra force only accelerates wear and raises temperature.
5. Monitor cooling throughout the entire process.
6. Reduce speed at the end — the bit breaking through the back side at high speed often causes chipping.

Drilling Already Installed Porcelain Tile

Drilling tile that is already laid is harder than drilling a single loose tile. The base beneath creates resistance, and any vibration transfers to neighbouring tiles. Take extra care when working near joints and edges. If the tile is installed on a wall, make sure cooling water does not seep into the joints or under the tile — this can compromise adhesive bonding. For more on the differences between working with floor and wall porcelain tile, read the article Wall vs Floor Porcelain Tiles: Key Differences.

Common Mistakes When Drilling

• Using hammer mode — the main cause of cracks.
• High speed from the very start — leads to surface chipping.
• Working without cooling — destroys the tool and can crack the tile.
• Pressing too hard on the drill — does not speed things up, it only causes damage.
• Drilling too close to the tile edge — the edge is the most vulnerable point, keep a minimum distance of 15–20 mm from the edge.
• Wrong angle — the drill must be held strictly perpendicular to the surface.

After Drilling

After the work is done, the tile surface often has traces left on it — porcelain dust, lubricant residue or cooling water streaks. These are not difficult to remove, but the key rule is never to use abrasive products on polished surfaces. For detailed advice on how to clean porcelain tile after construction work, read the article How to Clean Porcelain Tiles from Adhesive and Grout. If you are still at the planning stage and choosing your material, itum.ua offers a wide range of porcelain tiles with detailed technical specifications — so you can assess tile density and hardness in advance and choose the right tools for the job.