To paint a plastered cement wall, use a roller for open spaces and brushes around trim, applying an even coat of paint, recognizing that plaster is absorbent and often requires multiple coats.
Here's a more detailed explanation of the process:
Preparing the Wall
- Clean the Surface: Remove any dust, dirt, or debris. You can use a brush, vacuum, or a damp cloth.
- Repair Imperfections: Fill any cracks or holes with appropriate patching compound. Let it dry completely and sand smooth.
- Sand the Surface: Lightly sand the entire plastered surface to create a better bond for the primer. Remove sanding dust.
- Masking: Use painter's tape to protect trim, windows, doors, and any other areas you don't want to paint.
Priming the Wall
- Choose the Right Primer: Select a high-quality primer specifically designed for porous surfaces like plaster. Acrylic latex primers are a good choice. Some primers are also formulated to block stains or provide extra adhesion.
- Apply the Primer: Use a roller for the main wall area and a brush for corners and edges (cutting in). Apply a generous, even coat of primer.
- Drying Time: Allow the primer to dry completely according to the manufacturer's instructions. This is crucial for proper adhesion.
Painting the Wall
- Choose Your Paint: Use a high-quality latex paint suitable for interior or exterior walls, depending on the location of the plastered cement wall. Consider the sheen (matte, eggshell, satin, semi-gloss, gloss) based on the desired look and durability.
- First Coat: Apply the first coat of paint using a roller for the large areas and a brush for the edges and corners. Work in manageable sections to maintain a wet edge.
- Second Coat (and possibly more): Allow the first coat of paint to dry completely (as per the manufacturer's instructions). Because plaster is very absorbent, you will very likely need a second coat, and potentially even a third. Apply subsequent coats in the same manner as the first, ensuring even coverage.
Tips and Considerations
- Ventilation: Ensure adequate ventilation during painting by opening windows and using fans.
- Proper Tools: Use high-quality brushes and rollers for a smoother finish.
- Multiple Thin Coats: It's better to apply several thin coats than one thick coat to prevent drips and ensure even coverage.
- Clean Up: Clean your brushes and rollers immediately after use with soap and water (for latex paint).
- Check for Peeling: If the existing paint is peeling, scrape it off before starting.
- Efflorescence: If you notice a white, powdery substance on the plaster (efflorescence), remove it with a wire brush and treat the area with a masonry sealer before priming.
