Mold or mildew is a series of black, white, or grey colored patches that appear on walls, drywall, and wood. Can you cover these patches by painting over them?
You can paint over mold. Paint will stick and perform well on mold-infested areas. But, painting over mold is a temporary fix. Mold is an organism that thrives where there is moisture. So, if mold is growing on your walls or furniture, painting over it will not fix the problem or kill the mold permanently.
Regardless of how many coats of paint you put over the mold, it will still grow through the paint and you’ll have the same problem all over again.
But that’s not all. This post reveals more about painting over mold including a type of paint that can remove and prevent mold growth. So let’s dive in.
Do You Need To Remove Mold Before Painting?
It’s recommended to remove mold before painting. If you don’t remove the mold before painting over it, you’ll run into problems while and after applying the paint to the mold.
The first problem you’ll experience is poor paint adhesion. Since mold grows where there is moisture, it means that the surface where you have mold will wet. Also, mold has a moist texture. If you apply the paint to the mold-infested surface, the paint will not stick well due to the moist texture of the mold.
Oil-based paints especially will not stick or perform well on mold. This is because the oils in the paint will not stay on a wet area. This will lead to a sticky mess and a waste of paint.
Asides from poor paint adhesion, the paint will be affected by stains especially if you used paint with a light color shade like white yellow. Since there is mold and moisture underneath the paint, painting over it without removing the paint means that the mold and moisture will bleed through the paint to cause brown patches on the paint.
It’s also difficult to seal the paint if you don’t remove the mold first because the sealant will also be affected by stains and moisture. If you use a clear sealant on mold, the result will be terrible. Painting over mold can also cause the paint to crack, bubble, and peel.
So it is better to remove mold before you paint over it. You should also identify and fix whatever is causing mold to grow on your walls before removing the mold. This way, you’ll stop more mold from growing.
Does Painting Over Mold Stop It From Growing?
Painting over mold doesn’t stop mold from growing. Mold will still grow after you have painted over it. This is because mold is a fungus that grows anywhere there is moisture.
If you have mold or mildew growing on your wall or furniture, it’s because the furniture is constantly exposed to high moisture content. This could be a result of a rooftop leak, damaged plumbing pipes, or exposure to rainfall. If you don’t fix the leak or the cause of the mold, painting over it means the mold will still grow since the reason for the mold hasn’t been addressed.
Mold is more common on outdoor objects since these items are usually exposed to rainfall and cool air. Since mold is a living organism (fungi), water and air will make it thrive outdoors. So regardless of the number of paint coats that you put over the mold. It will still grow because you have not addressed the main problem. You only masked the problem by painting over it.
For instance, if the mold growth is a result of a roof leak and you paint over the mold, the new paint coating will still develop mold because you have not fixed the leak. As long as there is water and air, mold will grow.
However, there are paints advertised as “Mold-killing” primer or paint. These paints are formulated with fungicides to kill the mold and stop it from growing.
But after a while, such paints will develop mold if the surface is still exposed to high moisture content. So the best thing to do is to remove the mold before painting over it.
How To Paint Over Mold?
To paint over mold, you’ll need the following tools and supplies:
- A bottle of bleach or vinegar
- A bucket of water
- A pair of gloves
- A scrubbing brush or scraper
- A respirator mask
- Eye protection
- A gallon of mold-resistant paint primer
- A gallon of paint
- A sealant or top coat (optional)
Here is a quick rundown on how to do it:
- Repair the item
- Use a brush or scraper to remove the mold
- Spray and clean the affected areas with vinegar or bleach
- Apply two coats of a mold-resistant paint primer
- Apply a few coats of paint
- Seal the paint (optional)
Now, let’s get to work.
1. Fix The Mold Source
Usually, any item that has suffered mold infestation will be damaged. If it’s a piece of furniture, the wood may have developed rot. If it’s a wall, it would be stained and weak.
So you’ll need to repair the item first. You’ll also need to patch, seal, and repair leaks or anything causing mold to grow. When you have repaired and fixed the cause of the mold, you can move on to the next step.
2. Remove The Mold
The next step is to remove as much of the mold as you can. You should use a scrubbing brush or a scraper to remove the mold from the surface.
But before you start scraping the mold off, place a large drop sheet on the floor beneath the mold so as you scrape, the mold can be collected in the drop sheet and carried out easily later.
Mold can also be orange, white, brown, gray, or green. So if you see blots with these colors close to the mold, you should also remove them. Always wear safety gear when dealing with mold.
3. Spray and Clean The Affected Areas With Vinegar
To do this, fill a spray bottle with vinegar and spray the areas where mold grew. Ensure to cover the entire area with vinegar. You can also use bleach or household fungicide. Don’t use too much vinegar or mold-removing products as it has a strong odor.
Also, if you are working on a porous material like drywall, wood, and the likes, don’t spray the vinegar on the item. This is because these materials will easily suck the vinegar and in large quantities, the vinegar can damage wood, plaster, or drywall. Instead, soak a rag in vinegar and use the damp rag to wipe the affected surface.
4. Apply Mold-Resistant Paint Primer
Mold-resistant paint primer helps to prevent mold from growing on a surface. So this is a good choice to use on the item as it will prevent mold from growing on the paint.
You’ll need 2-3 light coats of mold-resistant primer for proper coverage. Ensure to allow each coat to dry before re-coating.
5. Apply a Few Coats Of Paint
You can apply the paint using a paint roller, paintbrush, or spray gun. Ensure to pick the right paint for the job.
Most manufacturers advise using 3 coats of paint for proper paint performance. After applying each coat, ensure to allow it to dry properly before applying the next coat.
6. Seal The Paint (Optional)
This step is based on your choice. But, sealing the paint after applying it helps to protect the finish.
The best sealants to use are waterproof sealants. While the mold-resistant paint primer prevents mold from growing beneath the paint, the sealant will prevent mold from growing on the paint. It’s like getting double protection.
Can Mold Bleed Through Paint?
Mold will bleed through paint if you don’t remove the mold before applying the paint. This is because mold has high moisture content.
Also, the organism reproduces by traveling as light moist spores. These spores can easily sift from underneath the paint causing a bleed-through of moisture and stains on the paint. Mold bleed-through is very common with water-based paints since the paint’s base (water) is a necessity for the mold to thrive.
But, mold will not sift through moisture-resistant primer or paint since these paints are formulated with mold-control additives like fungicides to repel mold growth.
Does Mold-Killing Paint or Primer Work?
Mold-killing primer does work but not in the way most people think while using it. Mold-killing paint or primer is designed to stop the growth of mold on a surface.
The paint or primer is usually a preventive measure against mold growth. The paint is usually incapable of destroying large blotches of mold or mildew on a surface.
Since the paint is designed to curb the growth of mold, it will cover the mold on the item for a while, usually about a few months. After a few months, mold will begin to grow again on the paint.
So you should only use mold-killing primer after you have cleaned the mold with vinegar.
How Long Does Mold-Killing Paint Last?
Generally, mold-killing paints aren’t known for their durability. Mold-killing paints aren’t built with additives that give them durability.
The additives in the paint are focused on preventing mold growth. Mold-removing paints usually don’t last up to 5 years.
This is why it is advised to seal the mold-killing paint after applying it. Zinsser mold-killing primer states to apply a top coat on the mold-killing paint within 72 hours for maximum protection.
Can You Paint Over Mold-Killing Primer?
You can paint over mold-killing primer. The paint given its special additives is still a paint primer meaning that it is designed to be an undercoat and not a top coat. So you need to paint over mold-killing primer.
Though you can leave mold-killing primer as the top coat, you wouldn’t get as good a finish as if you paint over the primer with a proper top coat. You can paint over mold-killing primer 1 hour after you applied the primer coat. The paint given its water-based nature dries quickly.
Can Mold Grow under Paint?
Mold will grow under paint, especially if it’s a water-based paint. If you don’t fix the root of the mold, then mold will keep growing regardless if you have painted over it or not. Mold-removing primers and paints won’t stop mold from growing, these primers will proactively prevent mold, but won’t remove it.
How to Tell if Mold Has Been Painted over?
To know if mold has been painted over, check the paint surface. If mold has been painted over, the mold color will bleed through the paint surface. The paint coating will have different colors. The paint coat will also be uneven and may develop bubbles.
Overall, you can paint over mold but only if you do enough prep work before applying the paint over the mold. Mold given its moist nature will not allow your paint to perform well so you should remove and clean the mold with vinegar before painting over it.
Remember, it’s better if you use mold-killing primer as a preventive measure rather than as the solution. Vinegar will clear out the debris better than mold-killing primer or paint.