5 Tiling Mistakes That Bathroom Pros Always See (and Wish You'd Stop Doing)

Whether you’re a bright color-loving maximalist or a neutral Scandi-style obsessive, there’s a bathroom tiling style that can appeal to any design philosophy. From large format marble slabs to patterned zellige tiles, it can be one of the most exciting design decisions you make when decorating your home — as long as you know the tiling mistakes you must avoid.

While the endless bathroom tiling ideas lure us in, tiling can feel like a high-risk, high-reward design choice. Installation is not always cheap — and if it is, you will likely end up paying the price eventually. From moldy grout to slippery floors, these tiling mistakes aren’t always the easiest to fix, so you’re much better off not taking shortcuts.

No matter how you decide to design your space, poorly done tiling can completely ruin your bathroom. But don't fear — our experts have covered the five most common bathroom tiling mistakes with their advice on how to avoid them, so you don't make the errors yourself.

1. Not Waterproofing

Whether you're looking to create a spa bathroom or just upgrading your current space, we wouldn't blame you for assuming bathroom tiles are inherently waterproof — it's a mistake made by many before, and no doubt many to come. However, it is worth knowing that some of the most popular materials are poorly suited to constant exposure to water.

Mike Whitfield, luxury interior expert at LUSSO shares: “Tiles are not automatically water resistant. For example, encaustic tiles made from cement and natural tile, such as marble, are naturally porous. Porous tiles will need to be sealed after installation, compared to ceramic and porcelain tiles which are virtually impervious to water.”

If you haven't already considered porcelain or ceramic tiles, these can be smarter options due to their resistance to water absorption. Mike explains: “As bathrooms are high moisture environments, surfaces are regularly exposed to water, steam, and humidity, you should choose bathroom tiles that have a low water absorption rate of less than 0.5%. Mosaic, terrazzo, and porcelain tiles are a great option for walls as they are designed to resist water, preventing issues such as cracking and mildew growth.”

However, as Farook Member, director, and bathroom design expert at QS Supplies says, "Even ceramic or porcelain can have varying water ratings, so make sure its rating is good before installing it." For minimal risk, and the best results, it's always a good idea to take the extra step and properly waterproof your tiles, even if you think you can get away without it.

"Using a waterproof membrane or cement board behind tiles prevents moisture damage and mold growth," recommends Amanda Leigh and Taylor Hahn from House of Rolison. And Courtney Cole, an interior designer for Tile Cloud says: "Waterproofing is a step that should never be skipped, yet it’s one of the most common mistakes people make."

She continues, "Even the best tile job won’t matter if water seeps into the walls or floors! Make sure that you are properly waterproofing before you start your tiling job."

2. Not Allowing for Slip-Ups

It's not just the material's ability to absorb water that you need to watch out for, the reverse can have equally risky results, especially on your bathroom floor tiles.

"In areas where water exposure is constant, it’s crucial to use tiles with a high anti-slip rating to minimize the risk of accidents," explains Mike. "Opt for tiles specifically designed for wet areas — such as matte porcelain — to provide peace of mind without compromising on luxury, quality, and style."

The risk of slipping on your tiles can be judged based on the R rating — or the more aptly named anti-slip rating. "The R rating, which stands for ramp test, has a varying range. It starts at R9, which has a small degree of slip resistance, up to R13, which is the highest slip resistance," Mike explains. "Not all tiles will have an anti-slip, or R rating — like gloss tiles, for example — and therefore could have a high slip potential meaning they need to be avoided in wetter areas."

As much as you may love the look of a high-shine tile, one slip is all it takes to make you instantly regret your decision. As Courtney puts it: "Polished porcelain might look sleek, but the moment water hits it, you’ll feel like you’re stepping onto an ice rink." No thanks.

3. Skipping The Prep Work

"Many DIY-ers skip prepping surfaces aside from layout," claims Farook. "It can result in issues when tiling on an uneven or weak substrate, where minute defects can result in cracks or weak adhesion later on."

It can be very tempting to try to simplify the process as much as possible, we've all been guilty of skimming over the steps we don't deem as important. However, it's time to put your own experience, or lack thereof, into perspective. We suggest taking some time to learn how to tile a bathroom and taking note of the expert advice before starting.

"Bathroom floors and bathroom walls need to be level, free of dust, and dry to begin tiling on top of them. It is most important around wet areas, such as around the bathtub or shower, because unless you watch out, water will creep behind and make tiles move or result in mold after a while. A good water buffer behind your tiles is not an added process; it is critical to ensuring your investment will endure," explains Farook.

4. Leaving Grout as an Afterthought

Often overlooked in planning, grout lines can make or break your tiling job — and you don't want to ruin all your hard work at the last hurdle. Whether the grout is a blobby mess oozing out the cracks, yellowing lines, or growing moldier by the minute, there's plenty of space to get it wrong.

The biggest issue with grouting is that "People only remember after is too late," as Farook says, "After it yellows, cracks, or grows moldy."

It can be tempting to view grout as an afterthought, an accessory to the main attraction, however, as soon as it begins to show faults, it will quickly become the most noticeable feature — and not in a good way. "Not properly closing up grouting or using poor grouting is also a frequent miscalculation that makes things more troublesome afterward," explains Farook.

It's not just the quality of the grout that needs to be considered, you should also take some time to think about the best grout color for bathrooms. As Courtney says, "So many people overlook grout, but the quality and color of the grout you choose will play a huge role in how the bathroom will look over time. For example, a bright white grout might seem like a great idea, but trust me, it won’t stay white for long —especially in a bathroom environment."

Farook agrees: "Light grouting is good-looking but is easy to stain, so if you wish to maintain that fresh appearance, use stain-resistant epoxy grouting or darker grouting that will stain much less readily."

Beyond color and quality, grout thickness is another aspect to pay attention to. "A useful tip is that the grouting should never be too thin," shares Farook. "Many assume thinner is better, but it is easy to break since it is rigid and can't move along with tile movement."

5. Going OTT

Even if you love a maximalist, colorful design, it can be easy to cross the line and overdo it with bathroom tiling. Mike explains: "Using too many colors or different types of tiles can easily overwhelm a space, creating a cluttered appearance." This is especially risky in small bathroom layouts, where you can easily feel suffocated by an overwhelming design.

"As a general rule," Mike says, "stick to no more than two tile styles within a kitchen or bathroom, as this keeps the design visually appealing and allows key elements, like feature walls or splashbacks, to stand out without competing for attention."

He continues: "For bathrooms, selecting one main tile and another for the floor provides a balanced, unified appearance. To create contrast, consider using tiles with a similar color palette but varying textures or finishes rather than introducing new colors."

Now you know the biggest risks to look out for, you can have some fun exploring the latest bathroom tile trends, including our current favorite — tile drenching. Or, if you're looking for more practical information, you may enjoy reading up on which bathroom tile is easiest to clean.