Is Latex Paint Waterproof? (Explained!)

So you want to put latex paint on a surface that will see moisture but you aren’t sure if latex paint is waterproof. Well is it?

Latex paint is not waterproof. For paint to be waterproof, the paint shouldn’t be damaged by water even if exposed to rainfall or moisture constantly. If you expose 100% water-based latex paint to constant moisture or rainfall, the paint will get damaged meaning that it’s not waterproof.

However, latex paint is water-resistant. This means that latex paint can and will withstand a certain level of moisture without going bad or peeling off. The reason for this is the synthetic latex in the paint coating.

The latex makes the paint coating stretch and cope in a moist environment. This is why you can clean and even wash your latex paint without it peeling off. Let’s take a closer look at this topic to find out more.

Is Latex Paint Water-Resistant?

Is Latex Paint Water-Resistant

Firstly, you should know that latex paint is not waterproof. The paint only has water-resistant qualities which makes many users think that the paint is waterproof.

For paint to be waterproof, the paint has to thrive under heavy rainfall and constant moisture. But, latex paint doesn’t thrive if there’s constant rainfall or moisture.

However, latex paint is water-resistant meaning that the paint can not be easily damaged by water. The reason latex paint is water-resistant is because of the synthetic latex in the paint coating.

The synthetic latex in latex paint is gotten from petroleum compounds. The latex in the paint makes the paint coating flexible enough to expand and contract based on temperature changes.

When the atmosphere gets moist, the latex paint particles will become tightly packed to prevent water or moisture from sifting through the paint coating.

This feature of latex paint makes it thrive in moist conditions longer than other paints would. This is why latex paint is water-resistant.

You should also know that latex paint can become waterproof if it’s sealed with a waterproof or water-resistant sealant after it dried. The waterproof sealant will produce a moisture-resistant film on the latex paint giving the latex paint coating improved resistance to moisture.

How Long Before Latex Paint Is Water-Resistant?

It takes between 4-6 hours for latex paint to become water-resistant. On average, latex paint will become water-resistant 5 hours after the final coat of paint was applied.

The latex paint will become water-resistant when it has dried enough or cured. To fully understand this, you need to know how latex paint dries.

After applying latex paint, the paint will be fresh and wet. In this state, the paint can be easily wiped off. This is because the solvent (or water) inside the latex paint is still present. As long as the paint is still wet, it will absorb moisture in the atmosphere making the paint water-soluble and nowhere near being water-resistant or waterproof.

When the latex paint had dried for about 2 hours, the solvent would have been evaporated from the paint coating. In this state, the latex paint is still not water-resistant because the paint particles haven’t hardened.

After about 5 hours, the latex paint will have completely hardened. The paint particles will become closely packed and it’s in this state that latex paint is said to have cured.

Also, in this state, the latex paint becomes water-resistant. You can clean, wipe, and wash the latex paint in this state without it coming off. The latex paint can even be exposed to moderate rainfall without any damages to the paint coating.

However, you should know that even in this state, the latex paint is still not waterproof. Though the paint can cope with moisture, it will still get damaged if you expose it to water constantly. So how can you make latex paint to be waterproof? Let’s find out.

How To Make Latex Paint Waterproof?

How To Make Latex Paint Waterproof

You can make latex paint waterproof by sealing the latex paint with a moisture-resistant or waterproof sealant. The waterproof sealant will prevent water and oils from penetrating the latex paint underneath. The sealant achieves this by drying to form a clear and thick film on the latex paint. This film will not let water penetrate and since water can’t get through the top coat, it can’t get to the latex paint underneath too.

To use this method, you’ll need to scuff the latex paint first with a fine-grit sandpaper. Then you can apply two to three coats of the water-based sealant on the latex paint and wait for the required time for the sealant to dry. When the sealant is dry, you should wait for 3 days before using or testing it.

You can also make latex paint to be waterproof by mixing the latex paint with a water-based moisture-resistant top coat or sealant. Sealants that can be mixed with latex paint include water-based polyurethane, polyacrylic, and exterior water-based varnish.

To do this, you’ll need to mix the latex paint with the water-based sealant in a paint bucket. Then apply the paint and let it dry. When the latex paint is dry, you’ll get a finish that is as colorful as latex and also as waterproof as the sealant.

Tip: Never mix latex paint with an oil-based sealant.

Does Rain Affect Latex Paint?

Rain does affect latex paint but only if the latex paint is exposed to heavy or constant rainfall. Latex paint is one of the most popular paints out there and one reason for this is because the paint is known to be very durable even on exterior surfaces.

As long as you don’t expose the latex paint to constant rainfall, you have nothing to worry about. Rain will only affect or damage latex paint if you expose the latex paint to rainfall or you use the latex paint on a horizontal piece of outdoor furniture.

If you put latex paint on a horizontal surface outdoors, then rainfall will affect the latex paint quicker. This is because horizontal surfaces like table tops are usually flat and the shape of the surface means that it will collect water.

In other words, when the rain stops, water will remain on the horizontal surface for extended periods. So if you coat the horizontal surface with latex paint, the paint will be affected by the water and it will eventually peel off.

However, on vertical surfaces like walls, the rain will not affect the latex paint as much because the water will roll down the wall as the rain falls. Since the water doesn’t stay on the wall, the latex paint is safe.

So in a way, rain will only affect latex paint if the latex paint is used on a horizontal object. Or, the latex paint is exposed to rainfall for extended periods.

Related Read: Can Latex Paint Catch Fire?

Can You Use Latex Paint On Bathroom Walls?

You can use latex paint on bathroom walls. This is because latex paint is water-resistant and as such can cope with the moist environment of the bathroom.

However, you should only pick latex paint that is washable for times when you want to clean or wash the bathroom walls.

Latex paint can be used on bathroom walls because the paint is water-resistant and as such, the paint will thrive in moist rooms. This means that the splashes of water, steam, and soap that get on the latex-painted walls will not affect the latex paint.

You can also use latex paint on bathroom cabinets, kitchen cabinets, and laundry rooms. However, always ensure the latex paint that you pick is washable and 100% water-based.

Related Read: How To Dissolve Latex Paint?

Final Words

Overall, latex paint is water-resistant and not waterproof. So if you’re to apply the paint on a surface that will see constant moisture, don’t! You should only apply latex paint on such surfaces if you will seal the latex paint or mix it with a waterproof sealant.

However, you can use latex paint on moist surfaces including bathroom walls, kitchen, and laundry rooms. The water-resistant qualities of the latex paint will make it thrive in such areas.

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