How to Prepare Plaster Walls for Latex Paint

Prep plaster walls by washing them first before sanding and applying paint.

Wall plaster, which is primarily composed lime or gypsum elements, sand and water has been used for centuries. The ancient Egyptians even used wall plaster in the same ways modern decorators do--to carry a unique design appeal while adding a strength and depth to wall surfaces. Preparing plaster walls for latex paint to create a smooth and easy-on-the eye visual requires a few simple tools.

Things You'll Need

• Bucket
• 1/2 cup of vinegar
• 1 cup of ammonia
• 1/4 cup of baking soda
• Stockings or socks
• Power sander
• Pole sander with extra fine-grit
• Acrylic primer/sealer
• Plastic covering
• Drop cloths
• Angled paintbrush
• Wall-joint compound

Instructions

1. Clean the wall. Mix 1/2 cup of vinegar, 1 cup of ammonia, 1/4 cup of baking soda in a gallon of warm water. Dip a nylon stocking or thick sock into the solution. Wring it out thoroughly. Apply the cleaning solution to the walls in even strokes.

2. Rinse the wall in clean water after the solution has been applied to all parts of the wall. Ventilate the room. Allow walls to air dry for at least three hours.

3. Inspect the plaster walls for holes. Fill uneven spots or holes with wall-joint compound. Apply a moderate amount of compound on a putty knife. Smooth it onto the plaster, feathering out in all directions as you maneuver away from the hole or wall damage.

4. Allow the compound to dry for a few hours before proceeding to sand the plaster down and before you reapply the compound a second time. Use a pole sander with extra fine-grit (150-grit is most preferred) to smooth the plaster down. Reapply compound. Allow the compound to dry completely.

5. Remove furniture or household fixtures in the room before applying paint on plaster walls. Cover the floor with a thick plastic covering. Use drop cloths on the plastic because they absorb paints better than plastic covering alone. Use blue painter’s tape on the wall’s edges or places that you do not want painted.

6. Use a high-quality acrylic primer/sealer to prevent painting from bleeding through the walls and to protect the wall from permanent oil, dirt and crud staining. Apply one to two coats of primer sealant with an angled paintbrush, beginning from one corner of the wall and extending it out to the rest of the wall in swift motions.

7. Allow the primer to set and dry for five hours or more. Apply desired latex paint color.

References

• Charles Supply: Plaster Washers
• Who, What, When, Where?: Preparing a Wall for Painting
• TLC: How to Clean Walls