Apply masking tape around the edge of the ceiling if you plan on repainting your walls later. This allows you to paint the walls more smoothly and effectively by leaving a space between the stucco and the top of the wall. If the walls won't be painted later, you don't need the masking tape.
Empty the room of furniture and lay down plastic drop cloths to prevent stucco from affecting the floor if it falls off during ceiling application.
Apply a primer to the ceiling with a paint roller to help the stucco bond with the ceiling more effectively.
Mix the stucco with water in accordance with package instructions for best results. Use an electric mixer for a large ceiling so the stucco continues to be mixed while you work on the ceiling to prevent it from solidifying during the application process. Otherwise, stir the stucco vigorously with a paint stirrer or a mixer bar.
Fill a mortar sprayer with your stucco solution once it reaches a consistent texture all the way through.
Use the sprayer to apply the stucco to the ceiling. Give the stucco at least four hours to start drying and then add a second coat for best results.
Run a paintbrush through the drying stucco to put imprints and designs into the ceiling. Push metal stencils or cookie cutters into the stucco to get specific shapes imprinted into the stucco.
Mist the stucco with water from a spray bottle every few hours as the stucco cures over the next several days.