How to Paint Flat Over Eggshell Finish

1. Clean the Surface: Wash the eggshell-finished surface with a non-abrasive cleaner and water. Allow it to dry completely before proceeding.

2. Sanding: Lightly sand the eggshell-finished surface with 220-grit sandpaper. The goal is to scuff the surface, not to remove the eggshell finish completely.

3. Dust Removal: Remove all the sanding dust with a tack cloth or vacuum.

4. Primer Application: Apply a coat of bonding primer to the eggshell-finished surface. Bonding primers are specifically designed for adhering to existing paint finishes. Make sure to follow the primer manufacturer's instructions for application and drying times.

Painting:

1. Paint Selection: Choose a flat paint that is compatible with the bonding primer and the eggshell finish underneath.

2. Paint Application: Use a high-quality paintbrush or roller to apply the flat paint in thin, even coats. Follow the paint manufacturer's instructions for recommended number of coats and drying times between coats.

3. Drying Time: Allow the flat paint to dry completely as per the manufacturer's instructions before moving furniture or hanging objects back in place.

Tips and Notes:

- Choose the right paint color and sheen to match your specific preferences.

- Ensure thorough coverage of the entire eggshell-finished surface to prevent any bare spots from showing.

- Use painter's tape if needed to achieve clean and sharp paint lines.

- If the eggshell finish has a noticeable texture or sheen, consider using a roller with a thicker nap to achieve a smoother finish with flat paint.

- Follow all safety precautions, like ensuring proper ventilation and protecting floors and furniture from paint spills.

- Remember that achieving a seamless conversion from eggshell to flat finish might require experimentation and practice based on the specific surface and paint used.