Can You Tile Over Tile? What to Know Before You Start

Replacing old tiles is a relatively common job that many DIYers take on without the help of a professional. One of the first steps is to remove the existing tile, but this part of the process can be difficult and time-consuming. Some DIYers skip the tile removal step entirely, choosing to install new tiles over existing tiles. However, this shortcut often leads to problems down the line, resulting in more time, effort, and money spent.

This doesn't mean DIYers can never tile over tile, but they must assess the situation ahead of time and avoid several common problems to complete this repair successfully. Use this guide to decide whether you should tile over tile.

Can You Tile Over Tile?

Tiling over tile is a shortcut that some DIYers and even some professionals take to cut down on the time and effort involved with the job. However, in some situations, the existing tile may be stuck to the walls with an overly strong adhesive, or the tiles may be so old they might crack, break, or crumble during removal. In these cases, it's often easier to install the new tiles over the old tiles, if possible.

Whether you can tile over tile depends on the condition of the old tiles, the weight restrictions of the walls or flooring, the type of tile adhesive, the height of the tiles, and the aesthetic appearance after the upgrade is complete. If the existing tiles have gaps or cracks or were installed unevenly, then the new tiles will have difficulty adhering to the damaged and uneven surface.

Similarly, if the walls cannot handle the extra weight of a second layer of tiles, they may buckle, bow, or begin to collapse after the new tiles are adhered to the wall. Floors don't usually have the same weight issues, but if the second layer of tiles adds too much height to the floor, it can impede the swing of the door or cause a permanent tripping hazard. Additionally, DIYers need to select an appropriate adhesive that can bond the front of the old tiles to the back of the new tiles.

Even if every step of the process works out, the second layer of tiles may protrude too far from the walls for the upgrade to look good, especially if the tiles stick out beyond the door trim or the edges of the double-tiled surface are visible.

Should You Tile Over Tile?

Now that you know you can tile over tile, the next question is whether you should. In most cases, tiling over tile is a bad idea. While it may take less time initially, there is a high chance of problems in the future. However, there are some situations where this installation method can work. Consider the benefits and drawbacks of tiling over tile before deciding on the route your project will take.

Benefits of Tiling Over Tile

There are several benefits to tiling over an existing tile surface that are important to weigh against the drawbacks of the job.

• Less time is required to install new tiling when the DIYer chooses to tile over the existing tile. Instead of spending half the time removing the old tiles, DIYers can skip to preparing the surface, applying adhesive, and installing new tiles.
• Prep time doesn't require as much effort since the existing tile surface is already smooth and flat. As long as the existing tiles were laid correctly, the new tiles should be able to be installed without any significant changes to the underlying material for a flat, level finish.
• It avoids damage to the existing substrate by skipping the tile removal process. Pulling up the old tiles can tear the drywall and damage the substrate, leading to time-consuming repairs. By tiling over the existing tiles, the DIYer doesn't need to worry about the underlying substrate or walls.
• It is easier to complete because the DIYer does not need to remove any existing tiles. Instead, they prepare the existing tiles, apply the adhesive, and cut and install the new tiles and grout.

Drawbacks of Tiling Over Tile

Tiling over tile is usually discouraged due to the potential issues that could arise as a result of this shortcut. Consider these drawbacks before deciding to tile over tile.

• Tiles may fall off the walls if the underlying tile surface is unsuitable for this job. This often happens if the existing tiles are uneven, cracked, or otherwise damaged, though it can also occur if the original tiles are not firmly attached to the underlying surface.
• Extra weight can cause the walls to bow or buckle, so it's important to consider whether the existing wall can handle the added weight of a second layer of tiles before proceeding.
• Extra height can interfere with functionality by blocking doors, covering baseboards, and protruding beyond door frames or window frames. The extra layer can negatively affect the aesthetic appeal of the upgrade if the tiles’ edges are visible.
• More time and effort are required if there is a problem with the installation. Tiles can come loose or even fall off the wall, leading to time-consuming patch jobs that may not solve the issue. If the problem can't be fixed with a quick repair, the DIYer might need to remove both layers of tiles and install a new layer before the job is complete.
  

What to Consider Before Tiling Over Tile

Despite the potential problems with this project, there are some situations where tiling over tile will work. If this shortcut still seems appealing, consider these five factors before starting this project.

1. Evaluate the Added Weight

Confirm that the wall can take the added weight of a second layer of tiles. If the wall cannot hold the combined weight of the existing tiles, the existing grout, the new adhesive, the new tiles, and the new grout, you have to remove the existing tiles and start from the bare wall or substrate.

2. Consider the Aesthetics

While some spaces can have a second layer of tiles added on top of the first with little visual difference, this isn't the case with all room layouts or bathroom setups. Take some time to determine how the upgrade will look and if the new appearance is appealing or if you should remove the existing layer to get the desired look.

3. Test the Functionality

When the extra layer of tiles blocks the swing of the door or creates a permanent tripping hazard for anyone living in the home, it's typically better to remove the existing layer of tiles instead of interfering with the functionality of the home.

4. Inspect Existing Tiles

When the tiles are uneven, damaged, or not firmly attached to the underlying surface, it can cause problems. Some slight gaps, cracks, and divots can be filled with adhesive to create a smooth surface, while minor protrusions might be ground down with a grinder. However, if there are significant issues with the condition of the tiles, it's better to remove the original layer and start from the bare wall or substrate.

5. Check for Moisture

Look for moisture issues behind the existing tiles. Adding an extra layer of tiles won't fix any ongoing moisture problems, so it's necessary to make any needed repairs to the walls and plumbing before proceeding.

Troubleshooting Tiling-Over-Tile Challenges

A range of issues can occur when taking a tiling-over-tile shortcut. Consider these methods for troubleshooting some of the challenges you might encounter.

• Tiles are not a good surface for secure adhesion. Already laid tiles are difficult for new tiles to grip, especially if the existing tiles have a smooth or glossy surface. In these instances, a DIYer can scuff the tile surface with sandpaper or a grinder, and then clean the tile surface before applying the adhesive. This should help the adhesive stick better to the existing tiles.
• The original adhesive may not work for tiling over tile. Not all adhesives can bond tile to tile, so before starting this project, it's necessary to research and test adhesive products that are suitable for the job. Speak to a knowledgeable employee at the local home improvement store or even reach out to a professional tiling company to determine what type of adhesive they use if they ever need to tile over tile.
• Extra height and weight may cause aesthetic and function problems. When the extra height of the second layer of tiles interferes with the door or protrudes too far from the wall, you can switch to a thinner type of tile that will fit better in the given space. However, in some cases, even switching to a thinner tile won't fix the issue. If this occurs, you must remove the existing layer of tiles to install the new tiles. Similarly, if the wall cannot support the extra weight of a second layer of tiles, there isn't a lot you can do to resolve the situation without removing the existing layer of tiles. 
• Existing tile placement and condition can affect the quality of the job. If the existing tiles are not level, you can use a grinder to grind off high spots for a smooth, even working surface. You can also apply extra adhesive to fill small gaps or level slight divots in the existing tile.