Putting tiles on concrete walls is similar to placing tiles on any other type of wall. The major difference is that preparing a concrete wall for tiles is different than preparing a plaster or drywall wall. You must ensure that the concrete wall provides a smooth, even subsurface so that all of the tiles rest flat against it. You can lay hard floor tiles on your concrete wall, or you can select softer tiles that are only appropriate for walls.
Place a 6-foot level on the wall in several spots to locate uneven areas. When the level's bubble is off centre, the level is resting on a bump or dent. Mark these spots by drawing a circle around them with chalk.
Chip away the bumps on the concrete wall with a hammer and cold chisel. If you create dents in the concrete instead of flat spots, do not worry; they will be filled in next.
Fill the dents, low spots and cracks with liquid concrete patching compound applied with a trowel. Scrape the wall with the edge of a 2-by-4 inch piece of scrap wood to make the patches flush with the surrounding wall. Smooth the surface of the patches with a trowel. Let the liquid patching compound dry according to the manufacturer's instructions, which is usually for a few hours.
Examine the finish of your concrete wall. If it is smooth, apply a liquid concrete bonding agent to the wall, following all manufacturer's instructions. This roughs up the surface so that the tiles can adhere to it. If your concrete wall is already rough, skip this step.
Measure the wall with a measuring tape and mark the midpoint along each edge of the wall. Snap chalk lines between the opposite lines, creating a vertical line and a horizontal line that intersect at the wall's midpoint.
Moving out from the centre lines, mark the wall edges in intervals equal to the size of three tiles. Snap chalk lines between opposite marks, creating a grid of vertical and horizontal lines that can be used as a guide when placing the tiles. Trace the lines with a permanent marker.
Apply mastic to one section of the wall with a notched trowel. Scrape the mastic with the notched edge of the trowel as you work to create grooves in the mastic.
Place the tiles on the mastic, using the grid lines as a guide to keep the rows and columns of tiles straight. The marker lines will show through the mastic. Put tile spacers between the tiles to leave room for grout.
Repeat Steps 1 and 2 until the entire wall is covered with tiles.
Tap each tile with a rubber mallet to push it into the mastic. Occasionally check with the level that the tiles are creating a flat surface; correct any unevenness by tapping raised tiles until they move into place. Let the mastic cure overnight, following the manufacturer's directions.
Remove the tile spacers. Scoop grout onto the wall with a grout float and press it into the spaces between the tile. Scrape excess grout from the tiles with the edge of the grout float and apply it to a different section of the wall. Continue until you have grouted the entire wall.
Wipe the remaining grout from the tiles with a damp sponge. Wipe the tiles two or three times to ensure that you remove all the grout residue before it hardens.
Run the corner of a damp sponge over every grout line, creating a consistent depth for each grout line. This is called jointing the grout and creates a professional look. First joint the vertical grout lines and then joint the horizontal grout lines. Let the grout dry overnight.