A textured wall must be sealed with a clear coat of varnish with a glosslike sheen. An alternative option is to paint the wall with eggshell or satin latex paint. To ensure you have not missed any areas, apply two coats. Any areas left unsealed immediately absorb the glaze, forming a dark area. Such an area cannot be fixed, and you'll need to repaint the entire surface. Look at the wall at a very close angle while shining a light on the textured surface. Inspect for any chalky or dull-looking areas where paint may have been missed. When painting, use a rough nap roller to ensure you are getting paint in all textured areas of the wall.
When mixing glaze for your textured wall, ensure you mix enough. Running out of glaze in the middle of your project may require you to repeat the project. It is difficult to estimate how much glaze you'll need. Most common glaze recipes call for 1 part latex paint to 4 parts clear glaze. For darker finishes, use a darker base coat or add in additional paint. Still, the more latex paint you use, the faster the mixture will dry. Glaze needs to stay wet as long as possible so you can manipulate it with paint tools before it dries. Always write down the exact amounts of paint and glaze you use, and label the paint bucket. A rough estimate for glaze and textured walls is about 1 gallon per 600 square feet of surface.
You can apply the glaze to the plaster walls with a variety of tools. These include old paint brushes, mini-rollers, plastic garbage bags and even crumpled-up newspaper. Experiment with the tools first, as each will give a different look. Always wear gloves to avoid glaze covering your bare skin.
Glazing plastered or textured walls may cause the glaze to absorb and dry quickly. Always work fast and use an assistant if needed. Start at the top of the wall, in the right or left corner, and work downward. Once at the baseboard, repeat the next section at the top of the wall, blending the sections together. All sections of glaze must stay wet to properly blend together. Work in a cool environment to avoid the glaze drying or becoming tacky.