To paint over concrete sealer, sand the finish, apply primer, apply paint, and seal the finish.
Paints don’t adhere over concrete sealer as the sealer forms a moisture-resistant layer that prevents paint adhesion.
You must either sand the top layer off or remove the entire sealer finish before painting.
Do Paints Adhere Over Concrete Sealer?
Paints don’t adhere over concrete sealer as the sealer forms a moisture-resistant coating that prevents water, moisture, and paint penetration or adhesion.
If you apply paint directly over the concrete sealer, the paint won’t penetrate the finish and will stay over the top layer until it gradually peels off.
Concrete sealer fills and seals surface pores and forms an impermeable layer to prevent penetration and protect the underlying surface.
However, you can paint over a concrete sealer if you sand or prime the sealer finish first. Sanding removes the moisture-resistant top layer and creates tiny holes (pores) that the paint can penetrate and adhere to.
Primer covers the moisture-resistant coating and forms a layer that the paint can adhere over. So, the paint adheres over the primer coating instead of the sealer coating.
How Long Must Concrete Sealer Dry Before Painting Over it?
Concrete sealer must cure (dry fully) for 24 hours before you can paint it. The exact dry and cure time depends on the sealer type, surface type, temperature and humidity levels, and coat viscosity.
Prep work is the reason concrete sealer must cure (dry fully) before painting over it. Since you must clean, sand, and prime the concrete sealer finish before painting, the sealer must cure and become hard (rigid) enough to withstand the sandpaper without getting damaged or removed.
If you paint over it too soon, the paint won’t stick well since the sealer is still wet. The finish will look gummy or sticky for several hours.
How To Paint Over Concrete Sealer?
To paint over concrete sealer, do the following things.
- Sand the Finish.
- Apply Primer (Optional).
- Apply Paint.
- Seal the Finish.
The tools you need for this project are listed below.
- Sandpaper (coarse, medium, and fine-grit).
- Paint-stripping compound.
1. Sand the Finish
To remove the concrete sealer’s moisture-resistant top layer and create tiny pores (holes) that the paint can penetrate and adhere to, sand the finish with fine-grit sandpaper (220-grit).
Fine-grit sandpaper isn’t abrasive (strong) enough to remove the entire sealer finish but will remove the moisture-resistant layer. If the sealer top layer is too strong, use medium-grit sandpaper (100-grit).
You can also remove the concrete sealer finish with coarse-grit sandpaper (40-grit) or a paint-stripping compound, and then apply paint.
2. Apply Primer
The primer coating covers the concrete sealer finish and forms a smooth layer that paint can penetrate and adhere to. The paint will adhere to the primer coating instead of the sealer coating.
Apply one (1) concrete primer coating over the sealer finish and allow it to dry.
Note: Applying a primer coating is optional if you sand the sealer finish.
3. Apply Paint
Apply 2-3 paint coats over the sanded or primed concrete sealer. The number of paint coats depends on how thick the existing finish is and whether you used a primer or not. The thicker the existing finish is, the fewer paint coats you need.
Wait until one coat dries before applying the next one.
4. Seal the Finish
Seal the new paint finish with a water-resistant sealer, such as polyurethane, varnish, or concrete sealer. Most paint types aren’t durable enough to protect outdoor concrete surfaces and will get washed off if exposed to weather elements (rainfall).
Can You Paint Over Different Concrete Sealer Types?
Water-Based Concrete Sealer
You can paint over water-based concrete sealer as it doesn’t have a glossy finish that repels paint as much. But, you must sand its top layer with fine-grit sandpaper (220-grit) before painting over it.
Acrylic Concrete Sealer
You can’t paint over acrylic concrete sealer unless you remove its entire finish first. This sealer has a shiny and elastic finish and fills concrete pores, preventing paints from adhering to it.
Penetrating Concrete Sealer
You can’t paint over penetrating concrete sealer as it penetrates the surface pores too deep and removing it is hard. You must use a paint-stripping compound to remove it as sanding doesn’t remove the sealer that penetrates the surface pores.