Painting Over Glossy Tile

Run a belt sander with an aluminum oxide sandpaper belt over the tile surface, dulling each tile. Don’t attempt to sand off the surface; just de-gloss it.

Brush primer over the tiles with a paintbrush in a thin, even layer, brushing all in one direction. Don’t put primer over the grout lines. Let the primer dry 12 hours.

Brush paint onto the tiles using a paintbrush, again in a thin, even coat with the brushstrokes going all in one direction. Don’t paint the grout lines. Allow the paint to dry for 12 hours.

Brush on a second coat using the same method. Let it dry 12 hours. Add a third coat. Let it dry 24 hours.

Apply a coat of polyurethane on the tiles in a thin, even layer. Let the polyurethane set for 12 hours.

Lightly sand the dried polyurethane, by hand, using fine sandpaper, just enough to dull the shine. Wipe up the dust. Brush on a second polyurethane coat. Let it dry 12 hours.