How to Install Tile Backsplash on Uneven Wall

Installing a tile backsplash can add style and personality to any kitchen. However, dealing with an uneven wall surface can complicate the project. With some planning and preparation, you can achieve a beautiful backsplash on a wall that is not perfectly flat. Here is a step-by-step guide for how to install tile backsplash on an uneven wall.

Assess the Wall and Plan the Layout

The first step is to assess the condition of the wall and identify any high or low spots. Look for protruding studs, uneven drywall seams, or areas that simply deviate from flat. Make note of the high and low areas and consider how to work around them.

It’s also important to map out the planned layout. Mark where the tile will start and stop, and sketch ideas for dealing with uneven areas. Consider adjusting the layout to avoid small high or low spots, or plan to build out the wall in places to compensate for more significant unevenness. Having a layout planned ahead of time will make the actual installation much easier.

Prepare the Wall Surface

To prepare an uneven wall for tile:

  • Sand down any high spots to make the surface smoother. Focus on sanding protruding drywall seams or screws.
  • Fill any low spots or dips with drywall joint compound to build those areas up flush with surrounding wall. Allow compound to fully dry before sanding smooth.
  • Skim coat larger low areas using thin layers of joint compound to gradually build up thickness. Sand between coats.
  • Prime entire wall surface with drywall primer when smoothing and filling is complete. This creates a uniform surface for tile adhesion.

Proper prep is crucial for success. Take the time to make the wall as even and smooth as possible before tiling.

Use a Cement Backer Board

Cement backer board, rather than drywall, is the ideal subsurface for tile in an uneven wall situation. It can span low and high spots better than drywall. Here are tips for installation:

  • Cut boards to fit your planned layout. Use full pieces when possible.
  • Screw boards in place using cement board screws, spaced 8 inches apart across stud locations.
  • Tape seams between boards with fiberglass mesh tape. Embed tape in a layer of thinset mortar.
  • Skim coat entire surface with thinset to fill any gaps, seams, and remaining unevenness. Let dry completely.

The cement board creates a strong, stable layer that compensates for wall irregularities.

Use a Thick Mortar Bed

Applying a thick mortar bed layer is key for an uneven wall tile installation. This can level the surface and prevent tile cracks or grout line unevenness.

  • Mix mortar to a stiff, almost dry consistency. The thicker the better.
  • Starting at the bottom, apply 1/4 to 1/2 inch layer of mortar over the wall area to be tiled.
  • Screed across the mortar using a straight board to smooth and level. Fill lows spots as needed.
  • Let mortar fully cure before installing tiles. This may take 24-48 hours.

Take the time to correctly build up the mortar bed. Rushing could lead to failure.

Mind the Tile Layout

When laying the tiles, careful planning can also help downplay any remaining unevenness:

  • Align tiles using laser levels or surface references, not just the wall plane.
  • Adjust tile spacing and alignment to prevent uneven or wide grout lines, especially at uneven seam locations.
  • Align tiles across any uneven wall areas rather than running tiles up and down.
  • Use smaller grout lines (1/8 inch or less) which look more uniform on uneven surfaces.
  • Incorporate tile patterns strategically, avoiding layouts like stacked subway tile which show imperfections.

Adjusting the tile layout can provide a beautiful finished look on a wall that is still slightly uneven.

Allowable Unevenness

How uneven can the wall be for a successful tile installation? Here are some general guidelines:

  • Up to 1/4 inch variation over 4 feet can often be compensated for with mortar bed and layout.
  • 1/4 to 1/2 inch variation may require more extensive smoothing and leveling work.
  • Greater than 1/2 inch unevenness across the surface is not recommended for tile. The wall likely requires significant structural repairs first.

Know when to call in a drywall pro to avoid taking on an overly ambitious backsplash project.

Grouting and Final Touches

With the tile installed, take these final steps:

  • Let tile mortar cure fully, generally 48-72 hours depending on products used.
  • Mix grout according to package directions. Apply grout using a rubber grout float. Push into joints firmly.
  • Clean excess grout off tile surface with sponge and water. Be careful not to pull grout back out of joints.
  • Caulk perimeter joints where tile meets countertop, ceiling, cabinets etc. Allow caulk to cure fully before wetting surface.
  • Seal grout and tile surface with grout sealer if desired. Allow sealer to fully cure.

Proper grouting and caulking will give a clean, finished look to your unique backsplash project.

With patience and proper planning, tile can be installed on even significantly uneven wall surfaces. Carefully assess the wall condition, compensate where needed with cement board and mortar beds, adjust the tile layout, and take care with final grouting. The result can be a stunning backsplash that compensates for any wall irregularities.

Frequently Asked Questions About Installing Tile on Uneven Walls

What’s the best way to determine how uneven a wall is?

Use a long, straight piece of wood or metal held against the wall surface to identify any gaps or inconsistencies. A 4′ – 6′ level is ideal. Measure any variations to determine the height differences. A wall may look flat, but this test will reveal high and low spots.

Should I use a leveling system for tiles on an uneven wall?

Leveling systems like tile spacers with built in leveling tabs can be useful, but may not work in cases of more extreme unevenness. Adjusting mortar thickness, the layout, and hand-aligning tiles often works better.

Can I just use more grout in uneven areas?

No. Grout should always be kept to the minimum effective thickness, usually 1/8 inch or less. Using extra grout to fill uneven areas can lead to cracking and failure.

What thinset mortar is best for an uneven wall?

Look for a mortar rated for large vertical installations, such as a medium bed thinset or one containing latex. These offer greater flexibility and adhesion over uneven surfaces.

Should backer board seams always fall over studs?

Ideally, yes. But for an uneven wall it’s more important to tightly space screws across the entire surface to prevent flexing. So putting seams between studs is acceptable if fastened tightly.

Can I use self-leveling compound instead of a mortar bed?

Self-leveling can work over very small areas, but it cures too quickly for larger installations. Mortar beds allow you to gradually build thickness as needed across the whole wall.


Installing tile backsplash on an uneven wall may seem like a daunting task, but with the right preparation and techniques, it can be accomplished successfully. The keys are properly assessing the wall condition, compensating for unevenness with cement board, mortar, and tile layout adjustments, and taking care with the final grouting and caulking. With planning and patience, you can achieve a stunning backsplash installation over wall surfaces that are less than perfectly flat. The end result will be a customized focal point that adds function and beauty to the kitchen.