Subway tiles, a timeless design choice for kitchens and bathrooms, can add a touch of elegance and sophistication to your home. However, even the most beautiful tiles can develop cracks over time. This can be a frustrating sight, leaving you wondering what went wrong. The good news is that there are several reasons why subway tiles crack, and many of them have solutions.

 

 

Understanding Subway Tiles

Before diving into the reasons behind cracked tiles, let's understand the materials involved. Subway tiles are most commonly ceramic or porcelain, both types of fired clay. Ceramic tiles are generally more affordable but slightly less durable than porcelain. Porcelain tiles are denser and less prone to water absorption, making them a good choice for high-moisture areas like bathrooms.

The tile itself is just one part of the equation. Subway tiles are adhered to a substrate, commonly drywall, using thin-set mortar, a specially formulated adhesive that ensures a strong bond. Grout, a cement-based filler, completes the installation by sealing the gaps between tiles. Together, these materials create the iconic subway tile look and offer functionality. That is why it’s important to identify and address the underlying causes of cracks when they occur, as neglecting them can compromise both the appearance and durability of your tiles.

 

 

Installation Issues

Subway tiles’ appealing qualities shine when installed correctly, but improper practices can lead to cracking and other issues over time. Understanding common mistakes and how to prevent them, can make a big difference in the durability of your tiles. Please note, that the tips provided here are general and for informational purposes only. For optimal results and to avoid potential pitfalls, consult a professional regarding your specific installation needs.

 

Improper Substrate Preparation

The foundation for a crack-free subway tile installation begins with proper substrate preparation. This process involves ensuring the underlying surface, typically drywall, is in pristine condition. To start, the installer must meticulously clean the drywall, removing any dust, dirt, grease, or contaminants that could hinder the adhesion of the thinset mortar, which bonds the tiles to the wall.

The next step is leveling. The installer should carefully check for any unevenness, such as bumps, dips, or warped areas. High spots can be sanded down, while depressions are filled with a patching compound suitable for drywall. Additionally, existing cracks in the drywall must be addressed, as they can compromise the entire tiled area. For example, hairline cracks can be repaired with a flexible joint compound, whereas larger cracks might require reinforcement with fiberglass mesh before patching.

Lastly, in moisture-prone areas like bathrooms or kitchens, it’s vital to ensure the drywall is completely dry before tiling begins. Excess moisture can weaken the bond between the tile and the substrate, ultimately leading to cracked tiles over time.

Inadequate Thinset Application

Thinset mortar plays a critical role in keeping your subway tiles securely bonded to the wall. However, improper application of this "glue" can lead to significant problems over time. To ensure proper adhesion, it’s crucial to achieve the right consistency when mixing the thinset, following the manufacturer’s instructions carefully. Thinset that is too dry won’t spread evenly or create a strong bond, while overly wet thinset will shrink as it dries, leaving tiles loose and prone to cracking.

Another common mistake is skimping on the amount of thinset used. For reliable adhesion, the thinset should be applied evenly across the entire back of each tile to ensure full coverage. Be sure to avoid "spot" application, where only small dabs of thinset are used. This method leaves air pockets behind the tiles, which weakens the bond and creates vulnerable points that can crack under pressure.

Lastly, after applying the thinset, it should be combed with a notched trowel. These ridges help create a mechanical bond between the tile and the thinset, enhancing the adhesion and preventing tiles from loosening or cracking in the future.

Grouting Problems

Don't underestimate the importance of proper grouting for your subway tile installation. Grout does more than just fill the spaces between the tiles; it plays a crucial role in supporting the entire tiled surface. But improper grouting techniques can lead to cracked tiles down the line.

Firstly, grout selection matters. Different types are formulated for specific applications. For wider grout joints, sanded grout is your friend, while non-sanded grout is better suited for narrow gaps. Using the wrong type can cause the grout to crack as it expands and contracts at a different rate than the tiles themselves.

Secondly, proper mixing is key. Grout that's too dry becomes difficult to work with and might not completely fill the joints, creating weak spots. Conversely, excessively wet grout shrinks more than it should as it dries, forming cracks in the grout lines and putting stress on the tile edges.

On top of that, ensure complete grouting. Incomplete grouting is a major culprit behind cracked tiles. The grout needs to be pressed firmly into the joints to ensure full contact with the tile edges and complete filling of the gaps. Skipping sections or leaving air pockets within the grout joints creates weak points that can easily crack under pressure or movement. By following these grouting best practices, you can help ensure your subway tile installation remains beautiful and crack-free for years to come.

Additional Installation Considerations

Beyond the points mentioned above, proper installation also involves aspects such as allowing for proper curing time for the thinset and grout before using the tiled area, as well as following recommended layout patterns to prevent excessive cutting of tiles, which can weaken them.

 

 

Movement and Stress

Subway tiles, while known for their durability, can sometimes suffer from cracks caused by movement and stress. This movement can stem from various sources, and understanding these culprits is crucial to preventing cracked tiles and maintaining the beauty of your tiled surface.

Structural Movement

While less common, cracks in subway tiles can sometimes indicate a more serious underlying issue with the building structure itself. Settlement of the foundation, which can occur over time due to various factors like soil conditions or changes in water levels, can cause the walls to shift ever so slightly. These subtle movements can put stress on the tiled surface, leading to cracks in the grout or even the tiles themselves. Similarly, structural movement within the building due to factors like expansion and contraction caused by temperature fluctuations or wind sway in high-rise buildings can also exert pressure on the tiles, causing them to crack.

Identifying cracks caused by structural movement typically involves looking for larger cracks that may run across multiple tiles or even extend beyond the tiled area onto the ceiling or adjoining walls. If you suspect structural movement as the culprit behind cracked tiles, it's crucial to consult a structural engineer to assess the situation and recommend appropriate solutions.

Thermal Expansion

Ceramic and porcelain tiles, while known for their durability, are not immune to the effects of temperature fluctuations. These materials have a slightly different coefficient of thermal expansion compared to the substrate they're adhered to, meaning they expand and contract at a slightly different rate when exposed to temperature changes. In areas with dramatic seasonal swings or environments with significant temperature variations, these expansions and contractions can become uneven, putting stress on the tiled surface.

This stress can manifest as hairline cracks in the grout or even cracks within the tiles themselves. To minimize the risk of thermal expansion causing cracked tiles, it's crucial to allow for proper expansion joints during installation. Expansion joints are small gaps strategically placed between the tiles and around the perimeter of the tiled area, acting as a buffer that accommodates the natural expansion and contraction of the tiles without putting undue stress on the tiled surface. Although this can help mitigate the risks, individual circumstances can vary, and consulting with a professional tiler for tailored advice is recommended for best results.

 

Tile Quality and Selection

Not all subway tiles are created equal. The quality and type of tile you choose can significantly impact its susceptibility to cracking. Let’s examine the factors to consider when selecting subway tiles to ensure they remain beautiful and crack-free for years to come.

Low-Quality Tiles

The quality of your subway tiles directly impacts their vulnerability to cracks. Cheaper, lower-quality tiles might have hidden flaws or inconsistencies from the manufacturing process. These imperfections can make the tiles more susceptible to cracking under pressure or stress. 

To ensure you're selecting the best tiles for the job, consider a few factors. First, opt for tiles from reputable brands known for their quality control standards. Second, if the area will be exposed to moisture, choose tiles with a low water absorption rating. Tiles that absorb excessive moisture can expand and crack as they dry out. Finally, before purchasing any tiles, thoroughly inspect them for any cracks, chips, or other imperfections. Even minor flaws can develop into bigger cracks later on.

Improper Tile Selection

Choosing the right tile is crucial to avoid premature cracking in your subway tile project. As previously mentioned, not all tiles are created equal, and different types are designed for specific applications. Installing wall tiles on the floor, for example, is a recipe for disaster. Floor tiles are designed to withstand weight and pressure, while wall tiles are not, and will inevitably crack due to heavy use.

The Porcelain Enamel Institute (PEI) rating system can be your guide here. This system classifies tiles based on their wear resistance. For busy areas like kitchen floors, opt for tiles with a higher PEI rating. These tiles are built to take a beating and are less likely to crack under everyday wear and tear. Finally, consider the thickness of the tile. While thinner tiles might look sleek, they may not be suitable for high-use areas or those prone to impact. Thicker tiles offer better structural integrity and are less prone to cracking under pressure.

 

 

External Factors

Beyond the intricacies of installation and tile selection, external factors can also play a role in the unfortunate cracking of subway tiles. We’ll explore these external influences and how to mitigate their impact on your beautiful tiled surfaces.

Impact Damage

Direct impact is often a primary cause of cracked subway tiles. For instance, accidentally dropping a heavy object can leave behind a visible crack that tells the story. A single crack radiating outward from a central point typically indicates a direct hit on that specific tile. However, with a more forceful blow, you may notice a spider web pattern of cracks extending from the impact site, potentially damaging multiple tiles or even compromising the substrate beneath the surface.

To minimize the risk of impact damage, exercise caution both during installation and in everyday use. Additionally, protective measures, such as using mats during installation and avoiding harsh cleaning techniques, can go a long way in preserving the integrity and appearance of your subway tiles.

Moisture Intrusion

Moisture exposure is another enemy of your subway tiles. In areas like behind showers that lack proper sealing or around leaky faucets, water can seep behind the tiles and cause significant damage. This moisture can lead to several issues that ultimately result in cracked tiles.

First, moisture can damage the substrate material behind the tiles, causing it to swell, warp, or even crumble. This compromised substrate can no longer adequately support the tiles, and as they shift or become loose, cracks will appear.

Second, moisture creates a breeding ground for mold growth behind the tiles. As mold grows, it exerts pressure on the tiles, eventually causing them to crack. Finally, in climates with freezing temperatures, trapped moisture behind the tiles can freeze and expand, causing the tiles themselves to crack.

To prevent moisture intrusion and safeguard your tiles, ensure proper waterproofing during installation, address leaks promptly, and maintain adequate ventilation in moisture-prone areas. Taking these precautions helps prevent moisture-related cracks and keeps your subway tiles looking beautiful for years to come. However, since individual conditions vary, it's advisable to consult a professional tiler to tailor these practices to your specific needs for the best results.

 

 

Repairing Cracked Subway Tiles

Repairing cracked subway tiles requires careful consideration of the severity and type of damage. While the tips provided here offer general guidance, it’s important to note that the best repair method for your specific situation may vary. Consulting a professional tiler ensures personalized advice and optimal results. Below, we’ll outline common scenarios and practical solutions to help restore your tiles and maintain the beauty of your space.

Hairline Cracks (Crazing)

Hairline cracks, often referred to as crazing, are fine surface fractures that commonly appear in older tile installations. While they typically don't pose a structural risk, they can diminish the overall visual appeal of your tiled surface. Addressing these minor cracks is relatively simple with a cosmetic touch-up using a grout stain.

Start by selecting a grout stain that closely matches the existing grout color for a seamless finish. Apply the stain carefully with a small brush or cotton swab, adhering to the instructions provided. Once the stain has dried, gently buff away any excess with a soft cloth to restore the polished look of your tiles.

Larger Cracks

Cracks that are wider than hairline fractures require a more substantial repair approach. The specific method depends on the size and location of the crack.

Grouting the Crack

For smaller cracks that don't go through the entire thickness of the tile, simply grouting the crack itself might be a viable solution. First, use a utility knife or grout removal tool to carefully remove any loose or crumbling grout from the crack. Clean the area thoroughly with a damp cloth to remove any dust or debris. Once dry, use a grout applicator or your finger to apply fresh grout, ensuring it completely fills the crack. Smooth the surface with a damp sponge and allow the grout to cure completely according to the manufacturer's instructions.

Replacing Individual Tiles

For more extensive cracks or cracks that compromise the integrity of the tile, replacing the affected tile(s) becomes necessary. This process requires careful removal of the damaged tile. Use a utility knife to score the grout line around the perimeter of the cracked tile. Then, using a chisel and hammer (with proper safety gear), gently tap the tile at an angle to break the bond with the thinset underneath. Once the tile is loose, carefully remove it without damaging the surrounding tiles. Clean the substrate thoroughly and ensure a level surface before applying a new thinset and installing a replacement tile.

Extensive Cracking or Underlying Issues

Widespread cracking or cracks that point to a more serious structural problem should be handled by professionals. Attempting a DIY repair in these situations is not advisable, as accurately identifying the root cause is crucial. Consulting an experienced tiler is essential to assess the damage, determine the underlying issue—whether related to installation, structural movement, or moisture problems—and provide the most effective solution.

The solution might involve replacing a large section of tiles, addressing structural concerns, or even re-tiling the entire area. Working with a professional ensures the issue is resolved thoroughly, preventing further damage and restoring the integrity of your tiled surface.

Additional Considerations

When repairing cracked tiles, matching the existing grout color and style is essential for maintaining a seamless, polished look. A close match ensures the repair blends harmoniously with the rest of the tiled surface, keeping the overall design intact.

For larger repairs, it’s always helpful to save a few extra tiles from the original installation. These spares can be used for future replacements, making it easier to address accidental damage while preserving the integrity and visual appeal of your space.

 

 

Preventing Cracked Subway Tiles

The frustration of cracked subway tiles can be easily avoided by taking proactive measures during installation and throughout the lifespan of your tiled surface. Here's a detailed breakdown of preventative strategies to ensure your subway tiles remain beautiful and crack-free for years to come:

Choosing the Right Installer

The foundation for a successful subway tile installation begins with selecting a skilled and reliable tiler. Start by confirming that the tiler is properly licensed and insured, which protects you from unforeseen issues during the project. Additionally, seek out a professional with prior experience working with subway tiles. Unlike generic tiling, subway tiles demand a unique understanding of their aesthetic and precise installation methods. To gauge the tiler’s capability, ask for references from previous clients and request to view their portfolio. Examining past projects also provides valuable insight into their quality of work, attention to detail, and ability to handle projects similar to yours.

Meticulous Substrate Preparation

As mentioned earlier, preparing the substrate properly is a crucial step in preventing cracked tiles. Given the variability in conditions and materials, it’s always wise to consult a professional tiler to ensure these steps are tailored to your specific project for optimal durability and long-term success.

Surface Cleaning

The first step in substrate preparation is thorough cleaning. The substrate, typically drywall in the case of subway tiles, must be free of dust, dirt, grease, or any other contaminants that could interfere with the adhesion of the thinset mortar. Proper cleaning ensures a strong bond between the tiles and the wall, forming the foundation for a durable installation.

Leveling and Smoothing

Next, the surface should be carefully inspected for any bumps, dips, or uneven areas. A flat and level surface is essential to creating an even bond and preventing future cracks. High spots can be sanded down, while low spots should be filled with a patching compound designed for drywall. Addressing these inconsistencies helps to eliminate pressure points that could lead to tile damage over time.

Crack Repair

Any existing cracks in the drywall should also be repaired before tiling begins. Hairline cracks can be filled with a flexible joint compound, while larger cracks might need reinforcement with fiberglass mesh before patching. Properly addressing these flaws ensures the substrate provides solid and reliable support for the tiles.

Moisture Control

In moisture-prone areas such as bathrooms or kitchens, it’s critical to ensure the drywall is completely dry before beginning the tiling process. Excess moisture can weaken the bond between the tile and the substrate, ultimately leading to cracking. Using a moisture meter to verify the dryness of the substrate is a valuable precaution to ensure a successful installation.

By following these detailed substrate preparation steps, you can greatly reduce the risk of cracked subway tiles and create a solid foundation for a long-lasting and visually appealing tiled surface.

High-Quality Materials

Investing in high-quality materials is essential for ensuring the longevity and crack resistance of your subway tile installation. Using premium components not only enhances the durability of your tiles but also contributes to their overall appearance and functionality.

Tiles

Start by selecting tiles from reputable brands known for their rigorous quality control standards. To make an informed choice, Edward Martin offers $2 samples, allowing you to assess the texture, color, and quality in your own space. A great tip is to choose tiles with a low water absorption rating for moisture-prone areas, such as bathrooms or kitchens. Additionally, visually inspect tiles for imperfections, such as cracks or chips, before purchasing to avoid future issues.

Thinset Mortar

The right thinset mortar is crucial for securely bonding subway tiles to the substrate. Opt for a mortar specifically designed for subway tile installations, and carefully follow the manufacturer's mixing instructions. Achieving the correct consistency is key to ensuring strong adhesion and preventing problems down the line.

Grout

Grout selection is equally important in maintaining the structural integrity and aesthetic appeal of your tiles. Sanded grout is ideal for wider grout joints, while non-sanded grout works best for narrower gaps. Proper mixing is vital—follow the manufacturer's guidelines to achieve the right consistency, ensuring full filling of joints and minimizing shrinkage as the grout cures.

Conclusion

Subway tiles, a timeless design choice, are not immune to cracking. Identifying the common causes, such as improper installation, low-quality materials, and stress from movement, equips you to take preventative action. Choosing a skilled installer, investing in high-quality materials, and selecting tiles suited to your space are essential steps for maintaining your tiled surfaces.

It is also important to address any cracks as soon as they appear. Doing so minimizes further damage and ensures your tiles remain beautiful and functional. With these proactive measures, you can keep your subway tiles looking stunning and durable for many years to come!