Enamel paint is oil-based and has a glossy topcoat that protects the surface better. So, can you apply enamel over cement paint?
You can apply enamel over unsealed cement paint. However, if the cement paint is sealed with a topcoat, you can’t paint over it unless you remove the topcoat first. To remove the topcoat, you must sand it or apply a paint-stripping compound.
However, you must use a stain-blocking primer before applying paint. That’s because the cement surface is porous and can damage the paint from underneath.
Enamel paint sticks to cement paint because it has impressive bonding qualities. Also, cement paint doesn’t have additives or a finish that repels paint.
Most cement paints are water-based, meaning they don’t have a glossy, moisture-resistant finish. Instead, cement paint has a dry textured paint that allows other paint to stick.
You must clean the cement paint before painting over it. This removes oils, grease, and stains from the coating so another paint can stick over it. If you clean the coating, enamel paint won’t stick well over it and might crack or peel off after a while.
Enamel paint will stick better if you sand the cement paint. Sanding will remove imperfections from the surface and create tiny ridges on the coating that the new paint can stick into.
However, if cement paint is acid-based, enamel paint can’t stick over it because the acid-based paints penetrate the surface deeply. To paint over acid-based concrete paint, apply a stain-blocking primer before applying paint.
How To Apply Enamel Over Cement Paint?
Applying enamel over cement paint isn’t hard. But, to get the best results, you must prep the surface by cleaning and sanding it before applying paint.
Here are the tools you need:
- Paint primer
- Enamel paint
- Clean rags
- A paintbrush
- Concrete paste or concrete filler (for repairs)
1. Clean and Degrease
First, clean and degrease the cement paint. Cleaning will remove oils, grease, stains, and dirt from the concrete that can prevent paint from sticking.
To clean a concrete surface, apply a diluted degreaser over the surface and wipe the stains off. After cleaning, leave the surface to dry for a few hours.
2. Sand The Paint
Sand cement paint with fine-grit sandpaper to remove imperfections and bumps from the coating. To sand the paint, use fine-grit sandpaper, not medium or coarse-grit sandpaper. That’s because coarse-grit sandpaper can remove the entire finish, while fine-grit sandpaper will only smooth it out.
If the cement paint is sealed, you must remove the topcoat first. To remove a sealant from paint, use medium-grit sandpaper or a paint-stripping compound.
After sanding the paint, remove the dust from the surface using a clean rag.
3. Apply Paint Primer
Apply a stain-blocking paint primer to prevent cement paint from bleeding-through enamel paint. Also, if the cement paint is acid-based, applying a stain-blocking primer is mandatory. Apply two coats of stain-blocking primer using a paintbrush or sprayer.
4. Apply The Enamel Paint
After the primer dries, apply enamel paint.
Here’s how to do it:
- 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.
Mixing Enamel and Cement Paint
You can mix enamel paint with cement paint only if both paints have the same base (or solvent). So, both paints must have the same solvent (water or oil) to be mixed. This means you can mix acrylic enamel with cement paint (water-based).
You can’t mix oil-based paint with water-based paint because oil and water don’t mix. If you mix two paints with different solvents, the mixture will have an inconsistent flow and color, and won’t stick.
Oil-based enamel and water-based cement paint have different drying times. So, if you mix them, the cement paint will dry while the enamel paint will still be wet. This leads to paint cracks because one part of the finish is dry while the other is still wet.
Also, you can’t mix enamel with acid-based cement paint. That’s because acid-based paints are compatible with oil-based or water-based.
How Long Does Enamel Paint Last?
On average, enamel paint will last 7 years over cement paint. However, the durability of the enamel paint depends on the type of paint, 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 sealant will produce a glossy transparent finish over the paint and protect it from moisture, water, scratches, and other damage. A good sealant for enamel paint is oil-based polyurethane.
You can apply enamel paint to a cement-painted surface, but you must clean and sand the surface first. Cleaning and sanding will remove dirt and imperfections from the surface, allowing enamel paint to stick better.
However, the best paint for cement walls is latex and not enamel paint. That’s because latex paint is more compatible with cement paint because they have the same solvent (water).
Tony is a professional painter and an author of DIY Geeks. Tony has completed over 1,000 painting projects for his clients. It's safe to say he knows what he Is talking about,