Step 9 · Install New Tile
After the waterproofing membrane has fully cured (check manufacturer's instructions), mix a small batch of thin-set mortar to a peanut butter-like consistency. Apply the mortar to the backer board patch using the flat side of a notched trowel, then comb it with the notched side to create even ridges. Firmly press your replacement tile(s) into the mortar with a slight twisting motion. Use tile spacers to maintain consistent grout lines that match the rest of the wall. Allow the mortar to cure for at least 24 hours before proceeding.