How To Repair Hairline Cracks In Ceramic Floor Tile

When installed correctly, tiles offer a robust, durable and practical solution for floors and walls throughout the home. However, this doesn't mean that they're completely devoid of problems. In some instances you may find your tiles have cracked, which can arise from a number of causes.

If this sounds familiar and you're facing the dilemma of a cracked tile or two, we're here, answering the all-important question: "my tiles are cracking, what do I do next?". Join us as we take a closer look at some of the reasons why tiles crack, as well as what you can do to fix them.

How can tiles crack?

Cracked tiles are usually the result of other underlying issues, mostly likely incorrect installation. However, it could also be due to extreme temperature changes, cracks in the substrate (or surface the tile is laid on), supporting too much weight or something as simple as a heavy item being dropped on them.

To help you better understand how to repair cracked tiles, you need to identify the cause and go from there. Here are a few more details on some of the most common reasons you may be facing cracked tiles in your home:

Incorrect installation

In order for a tile to deliver optimal performance, it's essential they're installed correctly. Otherwise you may find yourself with a whole host of issues, including cracked tiles. Tiling installation mistakes can be costly and includes:

Improper adhesive application: tiles should be fixed down with adhesive that covers the entire back of the tile. If there are any gaps or voids between the tile and the surface, this can impact their integrity, causing weak spots and eventually cracks
Unsuitable adhesion: tiles need to be securely fixed to the surface using adhesive with flexible properties that allows for small movements between rigid tiles and the substrate without impacting the stability of the tile. Using the wrong material like a grout or cement mix to apply tiles or not applying a flexible membrane can cause tiles to fracture

Hard impacts

Both ceramic and porcelain tiles are incredibly strong, but if subject to hard impacts like a heavy item being dropped on them, you may find they crack – particularly if there are other installation issues.

Bearing too much weight

As a rule, tiles are designed to support heavy loads, but not all tiles are designed for this application. For instance, if you install a wall tile onto floors, they may not be equipped to handle a heavy item like a fridge or washing machine for sustained lengths of time.

Cracked substrate

Particularly with floors, if the surface below the tiles cracks, it can also result in one or even multiple tile cracks above. This can be due to small movements such as concrete or wood expanding and contracting, or due to an installation without a flexible membrane or screed that stretches as the substrate moves.

Tiling over control joints

In large areas with concrete floors, you have control joints designed to allow for the material to expand and contract. If incorrectly tiled over without some form of flexible membrane, you may see fractures in these isolated areas.

Extreme temperature changes

Inside your home, temperature changes may be nominal and shouldn't drastically impact the integrity of your tiles. However, if you're using tiles outside that aren't suitable for outdoor use with frost-proofing properties, extreme temperature changes can make them more prone to cracking.

Unsuitable or low-quality tiles

Not all tiles are made equal and some variations aren't suitable for specific applications. As we mentioned above, using indoor tiles outside or installing wall tiles on floors can leave you more susceptible to tiles cracking in the long run.

Why do tiles crack?

When it comes to why tiles crack, the short answer is that the tile surface is put under too much stress that results in the material giving way and fracturing. These can be hairline cracks or more severe shattering, depending on the amount of strain the tile is put under.

Made from hard ceramic or porcelain that undergoes high heat and pressure during manufacturing, tiles are well-equipped to withstand heavy bearing loads, footfall, extreme temperature fluctuations, exposure to moisture, and not to mention their fair share of impacts. The problem often comes when external factors undermine their individual strength and durability.

Even if you don't have a vast understanding of the science involved in tile production and installation, it doesn't take a physics degree to know that any material will eventually break when put under pressure. This is exactly what happens with tiles.

Due to their rigid format, there's little to no give in tiles once they're in situ, meaning they rely on their surrounding environment to support them and ensure they remain in place and intact.

For instance, in the situation where the surface tiles are laid on is unstable or cracked, the tiles will be pulled in two different directions that puts stress on them in opposing areas. The result is a visible split in the tile surface.

Similarly, if they're undergoing strain due to heavy loads and aren't the right tile for this application, it's only a matter of time before the tile begins to buckle under the pressure of excessive weight. This is even more likely if tiles aren't installed correctly and have voids in the adhesive layer that creates weakened areas below the tile surface.

It also doesn't take a genius to work out that if you drop a heavy item from height, like a casserole pot or heavy-based saucepan, this will apply pressure and stress in a concentrated area of the tile, resulting in cracks and shattering.

What can you do to repair cracked tile s?

With a better understanding of how and why tiles crack, now it's time to look at what you can do to repair them. In most cases, you can repair tile cracks without having to shell out on a complete refit. Certainly with minor hairline cracks, you can use an epoxy filler to repair the tile surface. For bigger, more visible cracks you may need to remove the entire tile and replace it.

DIY tile fixes offer an affordable and convenient alternative to retiling a complete area – and we'll tell you exactly how you can carry out these tile crack repairs.

Minor cracks

Even though a lot of tile cracks aren't that noticeable, it's important to address them early. If you don't, you could end up with a bigger problem further down the line, as dirt, moisture and general wear will take their toll quicker.

Repairing small, hairline cracks is relatively simple with the right tools for the job. For this method, you'll need a small amount of clear epoxy (a specialist binding glue) and some paint that matches the colour of your tile.

Give the tile a thorough clean using washing detergent or a specific tile cleaner to remove any dirt and grime from the surface. Allow the tile and the crack to fully dry as this will ensure the epoxy has the best adhesion to the tile
Apply the epoxy along the crack, allowing it to seep down into the gap. Once the gap is filled, level it off with the tile surface covering 0.5cm either side of the crack and allow it to dry. Epoxy glue dries quickly, so be sure to work fast when applying it and try to avoid getting it on the unaffected areas of the tile.
Once dry, use a stanley knife to remove the excess epoxy from around the crack
Apply a layer of paint to tint the epoxy to match the colour of the tile

Large tile cracks

If you're stuck with a bigger crack or a shattered tile, the above method isn't an option. Instead, your best bet is to remove the tile and replace it with a spare tile in the same design, colour and size. If you don't have any spare tiles, you'll need to order new ones. However, keep in mind that tile batches can vary even with the same model, so there may be a difference in colour or finish than the original ones.

As tile fixes go, this one is a little trickier to pull off than the above. If it's not executed correctly, you run the risk of damaging the surrounding tiles and creating an even bigger job. Luckily, we've laid out the process in easy-to-follow steps below:

Using a special grout scraper, remove the grout from around the tile edge of the affected tiles. It's important to remove all the grout right to the edges as when you come to the next step, you won't impact any other tiles.
Lay an old towel over the cracked tile and smash it with a lump hammer right in the centre. By removing the grout and smashing the tile in the middle rather than trying to prize it out from the side, you avoid putting stress on the surrounding tiles and damaging them.
Remove the shards of broken tiles and chip out the remaining pieces that are stuck down using a chisel and hammer.
Next, use the chisel and hammer to remove any remaining grout and adhesive from the substrate and give it a final sweep out to remove all the debris.
Mix up a small amount of tile adhesive and apply to the underside of the tile using a notched trowel. Make sure you fully cover the surface to prevent air pockets once the adhesive is set.
Carefully place the new tile into the centre of the hole and gently press it into position, making sure the new tile lines up with the existing ones and is laid completely flat. Once in position, leave the adhesive to dry fully.
Next, apply grout into the gaps between the new tile using a grout float until the gaps are completely filled. Then take a damp sponge and wipe away any excess grout and allow it to dry overnight. Follow up with a wipe down to remove any grout residue and you're all set.

So there you have it, answers to those burning questions on how and why tiles crack, as well as some handy tips for cracked tile repair.

Of course, if repairing cracked tiles using the above methods isn't an option, you'll find plenty of premium-quality floor tiles and wall tiles right here, and our blog is packed full of ideas on how to use them, too!