Drilling tiles like a pro: Tips for damage-free holes

Tiles are predominantly made of terracotta, porcelain, ceramic, or stoneware, materials which differ in structure and properties. Terracotta tiles are soft, porous, glazed, and usually used as wall coverings. Stoneware tiles, meanwhile, have a much denser structure, making them extra robust and resilient and perfect for flooring. They can be glazed or unglazed.

Porcelain tiles, which are also available glazed or unglazed, are even more resilient. Thanks to their high density, they absorb almost no water, making them ideal for outdoor use. In addition to the materials mentioned, tiles can come in all different types, including baked clay, metal, and glass.

What makes a tile useful for construction is precisely what makes it so hard to drill through. Its robust surface requires significant force to penetrate, and its material composition means that cracking is common. When drilling, the drill bit can also slip on the tile’s smooth surface.

You can check how scratch-resistant (and therefore drill-resistant) a tile is by its Moh scale rating, which measures the hardness of materials from 1 (very soft) to 10 (very hard). Standard tiles have a rating of 3-4, while porcelain tiles are typically around 8, making them one of the hardest and more resistant tile materials.

The more wear and tear your tiles are subjected to, the higher rating they should have. To put this scale into context, diamond has a rating of 10 and can only be scratched by other diamonds.

When drilling tiles, it's important to use the right drill bit. Your chosen drill bit should be harder than the tile, so check the tile’s packaging for an indication of its Moh rating. If you’ve already disposed of the packaging, try to score the tile with the drill head. Use an offcut or non-visible part of the tile to do this. If you can make a scratch on the surface, you’ve found the right drill bit.

Often referred to simultaneously as glass and tile drill bits, these look like small spears and are easy to use even for beginner DIYers. The tip of the drill bit is incredibly sharp and easily penetrates tiles up to a hardness rating of 3. You must use cold water to cool off your glass drill bit after drilling the tiles.

You can also find special tile drill bits for soft and medium-strength tiles. These are essentially reinforced spiral drill bits with a diamond-ground cutting edge that enables effortless and precise drilling. Post-use cooling isn’t necessary with tile drill bits.

If you want to drill into very hard materials like stoneware and porcelain tiles, you’ll need a diamond drill bit. The tip is studded with fine diamonds that cut through almost any material effortlessly and precisely. During the drilling process, these bits constantly form new cutting edges and sharpen themselves, making them ideal for drilling hard tiles. You can find both wax-cooled and uncooled diamond drill bits. Wax-cooled bits don’t overheat during long drilling sessions, while uncooled bits must be cooled with water.

Masonry drill bits have limited suitability when drilling tiles and are best used when there is already a hole in the surface and the bit reaches the wall behind. The tip is coated with a hard metal plate that cannot penetrate tile cleanly. With a lot of patience and caution, however, you can drill decent holes in tiles up to a Moh rating of 3 with a masonry drill bit.

Once you’ve selected the right drill bit for your tiles, it’s time to prepare for your project. It’s crucial to make sure you’ve got all the tools, utilities, materials, and helpers you need before starting.

Before you begin drilling through your tiles, make sure there are no water or power lines behind them. Drilling into pipes and cables can be highly dangerous and expensive to fix. They’re particularly common in bathrooms and kitchens, so check for vertical and horizontal cables wherever there are sockets or light switches.

In general, installation areas of pipes and cables are around 30cm out from doors, windows, under the ceiling, and above the floor. This rule may not be reliable in old buildings, however, as cables often run diagonally. Therefore, always use a detector that can locate metal and weak current flow to find cables and pipes. Learn more about this in our guide to safe drilling. Although the risk of electric shocks is low, you should always switch off the fuse before drilling.

Next, measure the exact position of the drill hole and mark the spot with a water-soluble pencil. If you want to drill multiple holes, place a spirit level on the first mark and align it with your next intended drill hole.

To prevent the drill bit slipping on the smooth tile, we recommend centre-punching the hole beforehand. This creates a small indentation that holds the drill bit in place. To do this, place a centre punch or scriber on the mark at a slight angle and give it a few gentle taps with a hammer. You can also use a tough nail for this. If you’re using a diamond drill bit, this step isn’t necessary.

When drilling through tiles, it’s important that you proceed patiently and cautiously. Check out these handy tips for more information.

• • • There should be no cavity underneath the tile. You can check this by gently tapping around the tile; if it sounds the same everywhere, the tile is sitting firmly on the substrate beneath.
    • When drilling into porcelain tile, it’s worth pre-drilling holes. Start with a smaller drill bit diameter and work your way up to your desired size little by little, removing only a small amount of material at a time.
    • Always drill directly into the tile at a right angle, using a stencil or drilling template if necessary. If the drill bit tilts, the tile may be damaged.
    • Most drill bits heat up in the process and must be cooled with either drilling oil or cold water. Overheating damages the tool and creates tension in the material, potentially causing the tile to crack.
    • Tile and wax-cooled diamond drill bits generally don’t need cooling. Nevertheless, always pay attention to the heat created, particularly over long periods of time.
    • Ask a second person to hold a vacuum cleaner under the drill hole to catch any dust and debris before it spreads throughout your home. Alternatively, you can place a coffee filter or an open envelope with masking tape underneath the hole.
    • Always switch off the hammer or percussion functions of your drill, as the vibrations could damage the tile.
    • Apply a low pressure when drilling tile, as excessive force could cause the entire tile to crack. The drill speed should not exceed 1,000 rpm.
    • Standard tiles are typically 8-11mm thick. Switch to a masonry drill bit once you’ve reached this depth, as tile, glass, and diamond bits wear out quickly on masonry and stoneware floors. You’ll know when you’ve penetrated through the tile when the drill bit no longer brings up any loose material from the hole.
    • Continue drilling into the masonry at normal speed and with sufficient pressure. If you can’t make any progress, you can switch on the hammer or percussion function again.
    • The depth of your hole will depend on the wall plug you’re using. You can find useful information on choosing the right wall plug and hole depth in our extensive guide on drilling.

Mistakes can happen even with the best preparation. If you chip a drill hole or create it in the wrong place, you can fill any hole with a special tile levelling compound and remove any excess with a spatula. Once it’s hardened, carefully sand the surface with sandpaper and conceal any colour differences with spray paint. You can also cover the tiles with a decorative film. Check out our tutorial on renovating bathroom and kitchen tiles for more information.

You can also repair cracked tiles like this, provided they’re not in moisture-free rooms. Bathroom and kitchen tiles, however, need to be replaced if they’re broken as water could penetrate the cracks. Learn how to do this in our DIY guide on replacing individual tiles.

Things get a lot more challenging if you accidentally drill into a water pipe. If you do, you need to act quickly! Find out what to do in our guide on when the drill hits a water pipe.

Instead of drilling directly into the tiles, you can drill through the tile joints instead. This requires a lot less effort, and the holes can be easily covered up again later. However, only holes and wall plugs that are smaller than the joint itself are suitable. You cannot attach heavy cabinets like this.

Drilling through joints is much like drilling into tiles, except you use a masonry drill bit from the start. To prevent damage to the surrounding tiles, use a centre punch beforehand and switch off the hammer or percussion function on the drill. Apply a little force to drill through the grouting material, then continue drilling with added pressure once you reach the masonry.

If you live in a rented flat or house, you should think carefully about whether you really need to drill through tiles. Although your tenancy agreement may not explicitly refer to tiles, drilling holes in ceramic and porcelain tiles is generally a no-go if they’re not required for essential installations. If you drill into a wall without an agreement from your property’s owner, you may be required to pay for the damages. Always consult your landlord before drilling.

• For water-cooled drills, fill the tank with water.
• Attach the drill bit to the drill.
• Switch off the drill’s hammer or percussion function and set the rotation speed.
• Place the drill bit at a right angle to the tile.
• Drill through the tile.
• Regularly check the temperature and cool the drill bit if necessary.
• Switch to the masonry drill bit and drill to the desired depth.
• Remove adhesive tape and clean the drill hole.
• Insert the wall plug.

Below, you’ll find additional information to ensure your tile drilling project is a guaranteed success.

Special heavy-duty wall plugs are required if you want to attach heavy loads like kitchen cabinets to tiles. Remember that the wall anchor can only hold as much weight as its wall, so masonry or concrete walls are best. Special heavy-duty fixing sets are available for aerated concrete. If your walls are made of plasterboard, you shouldn’t attach anything weighing more than 40kg. For lighter loads, use cavity wall plugs.

You might be wondering whether it’s possible to drill a hole in the tile before you lay it. After all, this would make it easier to replace if it breaks. Drilling tiles before laying them is possible but not recommended. It simply takes too much time and effort to plan, as the holes in the tiles and the walls must exactly align with one another. Plus, you must hold the tile firmly in place when drilling and ensure it doesn’t vibrate.

Drilling isn’t the only method for fixing objects to tiles. Small and lightweight objects can be attached to the wall with double-sided sticky tape, for instance. There are also adhesive hooks and accessories that can withstand regular showers. And for heavy loads, you can use mounting adhesive to attach them to the wall – just remember to pay attention to the application instructions on the packaging.

• • • First things first: check whether you really need to drill into the tile or whether there’s another solution, such as joint drilling or using adhesive tape.
    • Use a detector to search for cables and pipes in the walls.
    • Choose the right drill bit. Use glass and tile drill bits for soft and medium tiles and diamond drill bits for drilling porcelain and natural stone tiles.
    • Centre-punch the drill hole beforehand to prevent the bit from slipping. Stick masking tape over the marked area for extra grip.
    • Switch off the percussion or hammer function on your drill and work carefully and cautiously, applying gentle pressure.
    • Regularly check the temperature of the drill bit and cool with water if necessary.
    • Always switch to a masonry drill bit to drill into the masonry behind the tile.

Did you manage to drill a clean hole? Excellent work! For additional DIY tips, check out our many other articles and tutorials about expanding your DIY knowledge...