How to Tile Over Vertical Concrete
- 1). Clean the concrete surface with a pH neutral cleanser. Use a power washer on external surfaces to remove any dirt or debris. Scrub the surfaces of internal walls, using a scrub brush. Rinse the surface of the concrete with clean water and allow the wall to dry completely.
- 2). Repair the surface of the concrete, closing any cracks or holes present. Completely remove any dirt from the cracks or holes, using a wire brush and clean the damaged areas with a scrub brush and water. Dry the damaged areas with a cloth and fill the cracks or holes with joint-repair sealant, leveling off the surface of the repair with the edge of a putty knife. Fill larger cracks and holes by lining the damaged area with a thin layer of epoxy gel adhesive to aid in bonding and filling the damaged area with shrink-resistant repair mortar. Allow the mortar to dry according to the manufacturer's suggested drying time.
- 3). Spread the entire surface of the concrete with asphalt mastic using the flat of a notched trowel. Go over the mastic a second time with the notched edge of the trowel to raise ridges in the material. The ridges aid in spreading the mastic evenly across the surface of the applied material. Wait 30 minutes for the mastic to set.
- 4). Place a layer of 4-millimeter polyethylene sheeting over the mastic to form a moisture barrier between the concrete and the tile. Overlap the plastic by 4 inches where the individual sheets of the material abut. Press the sheeting firmly to the mastic to secure it in place. Make cuts in the sheeting, using a utility knife where necessary around electrical outlets and ducts. Seal the edges of the cut plastic by applying a spray adhesive to the edges of the plastic and gluing it to the mastic. Spread a second layer of mastic onto the sheeting and wait 30 minutes for it to set into a surface suitable for the tile adhesive.
- 5). Mix a batch of thinset mortar in a large bucket, using an electric drill with a paddle attachment. Using the flat of the trowel, spread the mortar across a 4-by-4-foot section of the wall, starting at the top corner of the wall. Use the notched edge of the trowel to raise ridges and then place the tile onto the mortar, pressing firmly to secure it to the wall. Apply the tiles in a row across the wall, working your way downward. Place a piece of plywood onto the tiles and press down to ensure the tiles are level with one another.
- 6). Cut the tiles for the bottom of the wall, using a tile cutter, and place partial tiles. Leave a small gap of 1/4 inch at the bottom of the wall for trim placement. Wait four hours for the thinset to set.
- 7). Grout the tile surface to fill the joints and protect the tiles from moisture penetration. Spread the grout across the tile surface and push the grout into the joints between the tiles, using a grout float. Wait 15 minutes after grout application and remove any excess grout, using a damp sponge. Wait an additional two hours for the grout to begin to set. Remove the drying grout from the surface of the tiles, using a clean lint-free cloth. Wait seven to 10 days for the mortar to cure.
- 8). Seal the tile and grout to protect it from staining by brushing on a grout and tile sealant across the entire tiled surface. Allow the sealant to dry overnight.
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