How to Tile an Uneven Wall

Scrape the wall with your wide drywall knife to remove any loose material.

Use the knife to spread plaster over an area of about 4 by 4 feet on the wall. Run the knife at a steep angle so you lay the plaster on paper-thin on the flat spans but going deeper into the dips and depressions.

Repeat the plaster-application process for the next 4-by-4-foot section alongside the first one. Again, scrape the knife flat across the surface at a steep angle, so the plaster is laid very flat. Repeat for each 4-by-4-foot section, covering the whole wall.

Let the plaster dry for eight hours. Look at the wall from various angles, with bright lighting, to ensure that the shadows indicating dips are gone. If not, then repeat the skim coating process.

Let the final layer of skim coat plaster dry for 24 hours. Sand it smooth with a sanding pad.

Mark a horizontal line along the base of the wall your level and pencil, putting the line at the height of a tile plus 1/4 inch -- if the tiles are 6 inches across, the line should be 6 1/4 inches up from the floor. Mark a vertical line up the middle of the wall, intersecting the horizontal line.

Use your notched trowel to spread mastic over the base of the wall, from the floor up to the horizontal line and over the whole length of it.

Press the first course of tiles into the mastic, under the horizontal line, starting at the vertical line in the middle and working toward the sides. Put spacers between the tiles as you hang them. There should be a 1/4-inch space between the bottoms of the tiles and the floor. Cut the tiles at the ends on a tile cutter, as needed, to fit along the side walls.

Spread more mastic on the wall above the first course, and press the next course into place, again starting at the middle and working to the sides. Repeat, building up the wall course by course, putting spacers between all the tiles and cutting the end tiles as needed. Cover the whole wall.

Let the mastic set overnight. Pull out the spacers.

Spread grout over the tile surface with a grout float, pressing the grout into the spaces between the tiles and scraping it off the surface with the long edge of the float. Wipe up the residual grout with a damp sponge.