You can apply enamel paint over unsealed cement paint. Unsealed cement paint doesn’t have a glossy finish or additives that prevent paint adhesion.
You can’t apply enamel paint over sealed cement paint unless you remove the sealer’s glossy topcoat first.
Does Enamel Paint Adhere to Cement Paint?
Enamel paint does adhere to cement paint as it has impressive adhesive qualities. Most cement paints don’t have additives or a finish that will repel the paint as they are water-based.
Since most cement paints are water-based, they don’t have a glossy or moisture-resistant finish that prevents paint adhesion. Instead, cement paint has a dry textured finish that allows new paints to stick over it.
You must clean and sand the cement paint before painting over it to remove oils, grease, and stains that prevent paint adhesion. If you don’t clean the paint, enamel paint won’t adhere properly over it and might peel off after application.
Sanding will remove imperfections and bumps from the cement paint, create tiny pores (holes) in the finish, and leave behind a smooth and textured finish for enamel paint to penetrate and stick to.
You can’t apply enamel paint over acid-based cement paint as the paint has already penetrated the surface too deep and will prevent penetration. To paint over acid-based concrete paint, apply a stain-blocking primer before applying paint.
How To Apply Enamel Paint Over Cement Paint?
To apply enamel paint over cement paint, do the following.
- Clean and Degrease the Cement Paint Finish.
- Sand the Finish.
- Apply Paint Primer.
- Apply Enamel Paint.
The tools you need for this project are listed below.
- Paint primer
- Enamel paint
- Clean rags
- A paintbrush
- Concrete paste or concrete filler (for repairs)
1. Clean and Degrease the Cement Paint Finish
Clean and degrease the cement paint finish to remove dirt, dust, oils, grease, and stains that can prevent paint adhesion.
To clean the cement paint, use soapy water and wipe the finish with a clean cloth. After cleaning, leave the surface to dry.
2. Sand the Finish
Sand the cement paint with fine-grit sandpaper (220-grit) to remove imperfections and bumps from the coating that prevent paint adhesion.
Use coarse-grit sandpaper (40-grit) if the cement paint is sealed as you must remove the glossy topcoat before painting over it. To remove the sealer, you can use a paint-stripping compound as an alternative to sanding
Re-clean the finish with a clean rag after sanding it.
3. Apply Paint Primer
Apply two (2) coats of stain-blocking primer over cement paint to prevent it from bleeding through the new finish.
If the cement paint is acid-based applying a stain-blocking primer is necessary.
4. Apply Enamel Paint
To apply enamel paint, do the following.
- Use a paint roller, brush, or sprayer to apply it.
- If you use a sprayer, thin enamel paint with mineral spirits (ratio of 4:1).
- Apply 3-4 coats of enamel paint to cement paint.
- Wait until one coat dries before applying the next one.
- Allow the final coat of enamel to dry for 3 days before using it.
Optionally, you can seal the finish with a polyurethane topcoat.
Can You Mix Enamel and Cement Paint?
You can mix enamel paint with cement paint only if both paints have the same base or solvent. Both paints must be either water-based or oil-based to be mixed.
You can’t mix oil-based enamel paint with water-based cement paint, or vice versa. If you mix paints with different solvents, the mixture will have an inconsistent flow and color, and won’t adhere properly.
You can’t mix enamel paint with acid-based cement paint as they aren’t compatible.
How Long Does Enamel Paint Last Over Cement Paint?
Enamel paint lasts around 7 years over cement paint. However, the durability of the paint depends on its type, how well it was applied, and where is the cement (or concrete) surface placed.
For instance, on outdoor concrete, enamel paint won’t last more than 3 years. That’s because the paint isn’t durable enough to withstand weather elements such as rain, and the paint will peel off. However, on indoor concrete, enamel paint will last up to 7 years because indoor concrete isn’t exposed to harsh weather elements.
The paint will last longer if you seal it. A sealer will produce a glossy transparent finish over the paint and protect it from moisture, water, scratches, and other damage. A good sealer for enamel paint is oil-based polyurethane.