Concrete sealers are used to prevent damage, corrosion, and staining on concrete surfaces. But, concrete sealers are clear and boring to look at. So, can you paint over them?
You can paint over concrete sealer but you’ll need to clean, sand, and prime its top layer first. The prep work is to abrade the coating and remove the top layer, so the paint can stick better.
However, some types of sealers can’t be painted over, so you must tint them before you apply them.
Concrete sealers when dry form a moisture-resistant layer that prevents moisture from penetrating. Since moisture (liquid) can’t penetrate their coating, paint won’t stick.
If you apply paint directly over it, it won’t stick and will come off in a few days or weeks. Also, it will take very little effort or contact to wipe the coating off it.
Concrete sealers as the name implies are coatings designed to repel moisture and liquid. The sealer prevents damage and stains from affecting the concrete surface underneath.
They seal the pores with resins and silicon-based materials or by forming an impermeable layer on to prevent penetration. Either way, one thing is sure, the paint will not stick to sealed concrete.
However, if you clean, sand, and prime the sealers, you can paint over it. That’s because sanding will create tiny pores on its coating and remove some parts of the sealers. This allows paint to penetrate into those pores/parts and stick.
Also, priming helps to provide a smooth undercoat for the paint to be applied. This gives the finish a smooth and fine texture.
Dry Time Before Painting
The concrete sealer must fully dry before you can paint over it. On average this takes 8 hours. However, its dry time depends on the number of coats applied, room temperature, and humidity levels.
The reason the concrete sealer must be fully dried is because of the prep work required. Before you can paint over it, you must clean, sand (abrade), and prime it. If the sealer is still wet you can’t do it as you will remove the entire finish.
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?
Painting over concrete sealer is not the easiest of tasks because by design it will not allow paint to stick. So you need to alter its texture first.
Here are the tools you need:
- Medium Grit Sandpaper
- Fine Grit Sandpaper
- Chemical Paint Stripper
- The Required Paint
- A Sealant (optional)
Note: The concrete sealer must be fully dry before you paint over it.
1. Sand The Finish
You must sand the sealer to create tiny pores (holes) that the paint can penetrate to.
To do so, use medium-grit sandpaper (150-200-grit). The sandpaper isn’t strong enough to remove the entire finish, so it will just abrade it. Sanding will also remove imperfections from the finish that can prevent good adhesion.
You can also remove the entire sealer finish and then apply the paint.
To remove it:
- Apply paint-stripping compound over it.
- Wait 15 minutes.
- Scrape the stripping compound (the sealer will come off too).
- Clean the surface.
- Sand it with fine-grit sandpaper.
2. Apply Two Coats Of Primer
After sanding the sealant, apply two coats of primer using a brush. The primer will produce a textured coating that helps the new finish to stick to it. So, the paint will stick to the textured layer of primer, and not the glossy finish of the sealant.
Ensure to use a primer designed for concrete surfaces. Wait until one coat dries before applying the next one.
3. Apply The Paint
For high-traffic concrete surfaces that are exposed to constant usage, use epoxy or masonry paint. For indoor concrete surfaces, use any type of paint you want. It’s recommended to apply up to 3 coats of paint. You usually don’t need to sand between coats, but light sand will improve the adhesion.
4. Seal The Finish
After the final coat dries, seal the finish with a sealant. Most paints aren’t durable or strong enough to protect the concrete surface from damage. So, you must seal the finish with a waterproof sealant. Use polyurethane, concrete sealer (again), or spar varnish.
Different Types of Concrete Sealers
You can paint over water-based concrete sealer because it has a low level of solvents, resinous compounds, oils, and silicon-based materials. Also, its finish isn’t as glossy, so it doesn’t repel paint as much.
You can also use water-based sealer as an undercoat before painting over it. The sealer is stronger and more durable than a primer and protects the surface better.
However, you still have to abrade (sand) its top coat off before painting over it. If you don’t, the new coating won’t stick.
You can’t paint over acrylic concrete sealer unless you remove the entire finish first. This is because this sealer is shiny and elastic and has a rubber-like texture that makes it difficult for paint to stick over it.
Also, they tend to fill the pores in the concrete making it difficult for any other coating to adhere well to it. Simply abrading or scuffing its finish won’t work because it has a flexible nature that shifts and moves based on temperature changes.
You shouldn’t paint over penetrating concrete sealers. That’s because they penetrate the surface by sifting through the pores and hairline cracks. Since the pores are already full, no coating will stick over it since it can’t penetrate the pores.
The only way to paint over it is to remove the entire finish first.
Tinting The Sealer
Concrete sealers are clear coats, meaning they have no pigments in their formula, so their finish is transparent. This is because they are designed to be used over an existing finish, and reveal their color shade.
However, you can tint the concrete sealer by adding a few drops of colorants (or pigments) before applying it. After mixing them, you will get a finish that is durable and moisture-resistant, but at the same time colorful.
In summary, painting over concrete sealer is possible, but you must clean, sand, and prime it first. Sanding will abrade the finish by creating pores that the paint can penetrate. Priming will create a textured coating over the finish to improve the adhesion.
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,