How to Put Floor Tiles on the Ceiling

Measure the ceiling and lay out the tiles on a floor, using the ceiling measurements as a template. Use a full tile at the back, center of the ceiling and radiate out the tiles from this point in rows. Cut the edge tiles on a tile saw and double-check their fit in the template before installing.

Spread a Portland cement-based mortar directly onto the backs of the floor tiles. Comb the cement with the teeth of the trowel and firmly press each tile to the ceiling, twisting it slightly to create a good bond. Tile each row front to back and stretch a piece of painter's tape across them to hold them temporarily in place.

Lay a 2-by-4 across each short, finished row of ceiling tile. Stand a longer 2-by-4 vertically to intersect with the first board to form a "T." Place shims beneath the vertical board to create a tight fit between the boards, holding the tiles in place while they dry. Leave these boards in place for a minimum of 24 hours.

Spread grout across the ceiling with a grout float. Drag the float across the ceiling at a 45-degree angle to the tiles to spread the grout; flatten the float to the ceiling to press the grout between the tiles. Wipe the surface of the tiles clean with a damp sponge.