Is Chalk Paint Waterproof? (Explained!)

Chalk paint has some impressive qualities. The paint dries fast, it’s easy to apply, and the finish is colorful. But is chalk paint waterproof?

Chalk paint is not waterproof but the paint is water-resistant. This means that chalk paint can withstand a degree of moisture without getting damaged.

But if the chalk paint is constantly exposed to rainfall or moisture, it will get damaged. As a result, chalk paint isn’t great for outdoor furniture or surface that will experience rainfall.

However, chalk paint can be made to be waterproof by sealing the chalk paint with a waterproof sealant like exterior polyurethane. The sealant will give the chalk paint waterproof qualities. Check out the guide down below.

What Makes Chalk Paint Water-Resistant?

What Makes Chalk Paint Water-Resistant?

The first thing you should know is that chalk paint is not waterproof but is water-resistant. Both these terms are wrongly used interchangeably. A waterproof paint means that the paint can not be affected by water even if exposed to rainfall. A water-resistant finish means that the paint can withstand light moisture without getting damaged.

Chalk paint is water-resistant. This is why you can wipe and clean your chalk paint with a wet rag without the paint coming off. But, if you pour water on the chalk, the paint will get wet and peel off.

The next thing you should know is that acrylic chalk paint is the water-resistant type of chalk paint. The reason acrylic chalk paint is water-resistant is that the paint coating includes acrylic polymer and binders that keep the paint particles tightly packed together. As such, it becomes difficult for moisture to penetrate the paint coating.

Chalk paint is more water-resistant on vertical surfaces like walls. This is because moisture or water will not stay on such surfaces for extended periods. Even during rainfall, the water runs down the wall meaning that water isn’t staying on the chalk paint for a long time.

However, on horizontal surfaces like tabletops or benches, chalk paint is not water-resistant. This is because moisture will stay on such surfaces for hours since the surface is flat. You should also know that some chalk paints have additives included in the paint formula to make the chalk water-resistant.

How To Tell If Chalk Paint Is Waterproof?

To tell if chalk paint is waterproof or not, you can check the container of the chalk paint. The information about the paint is usually inscribed on the container and if the paint is waterproof, it will be indicated there.

Another way to tell is by putting water on the chalk paint after it has dried. You need to pour water on the chalk paint and let the water sit on it for a few minutes, usually, about 30 minutes. After 30 minutes, check on the chalk paint.

If you can see the water on the chalk, it’s a sign that the chalk paint is waterproof. But if you notice that the water has been tinted or the water has taken the color of the chalk paint, it means that the chalk paint is not waterproof and the paint is coming off. If the chalk paint is waterproof, the water you put on it will still be clear.

Also, if you can’t see the water that you applied or you notice that the chalk paint has turned liquid, it means the chalk paint isn’t waterproof. If the chalk paint has changed form or is looking, faded, wet, lumpy, or blistered, it also means that the chalk paint isn’t waterproof.

If the paint is waterproof, the water wouldn’t change the form of the paint or affect it in any way. Any changes in form or color mean the chalk paint isn’t waterproof.

How To Make Chalk Paint Waterproof (Made Easy)?

The best way to make chalk paint waterproof is to seal the chalk paint with a waterproof sealant. Good choices include exterior polyurethane, polyacrylic, wax, and lacquer. These sealants are water-resistant and will give the chalk paint waterproof qualities. To make chalk paint waterproof, you’ll need the following tools and supplies:

  1. Fine-grit sandpaper
  2. A paintbrush
  3. A waterproof sealant
  4. Clean rags

Here is a quick rundown of how to make chalk paint waterproof:

  1. Clean and scuff the chalk paint with fine-grit sandpaper
  2. Apply two coats of a waterproof sealant on the chalk paint
  3. Leave the sealant to cure for 3 days before use.

Now, let’s get to work.

1. Clean and Scuff The Chalk Paint

Clean and Scuff The Chalk Paint

The first step is to clean the chalk paint with a rag and then sand lightly with fine-grit sandpaper. 220-grit is good enough for this. The purpose of scuffing the chalk paint is to create tiny ridges in the chalk paint that the sealant can bite into. This promotes good adhesion.

After scuffing the chalk paint, you are sure to have dust and chalk residue on the surface. These should be removed as dust can affect the smoothness of the finish. Dust nibs can produce lumps and pimples in the sealant when it’s dry. You can remove dust using a portable vacuum or a soft brush.

2. Apply Two Coats Of A Waterproof Sealant

Apply Two Coats Of A Waterproof Sealant

With the chalk paint properly scuffed and clean, it’s ready to accept the sealant. As explained earlier, you can pick any sealant as long as it’s waterproof. It’s advised to pick sealants designed for exterior use.

Such sealants are usually reinforced with additives to make the sealant thrive under heavy rainfall. Chalk paint isn’t picky and will allow even oil-based sealants to stick. For this guide, I’ll be using exterior polyurethane.

Before you can use the sealant, you might need to prep it by thinning, mixing, or shaking it first. Follow the manufacture’s instructions for this.

For exterior polyurethane, the sealant comes in a spray can so all you need to do is shake the can lightly to mix the content. Don’t shake too hard or you’ll cause bubbles to form inside the spray can.

Apply the first coat of the sealant and leave it to dry. If you are a beginner, you should apply the sealant using a spray gun as this gives you good coverage of the chalk paint and a smooth result.

You can use a paintbrush if you are experienced. When the first coat is dry, apply the second and let it dry too. If required, you can sand between coats.

3. Leave The Sealant To Dry

Leave The Sealant To Dry

After applying two coats of the waterproof sealant, you should leave the paint to dry. It’s best to leave the sealant for at least 3 days so it can cure. When the sealant has cured, the chalk paint underneath will become waterproof.

Does Rain Affect Chalk Paint?

Rain does affect chalk paint. Heavy and constant rainfall on chalk paint will ruin the paint and cause it to peel off.

But rain is more likely to affect chalk paint that is applied on a horizontal or flat surface. This is because the rain will fall and stay on the chalk paint since the surface is flat.

But on vertical surfaces like walls, the effects of rainfall on the chalk paint is limited. This is because the rain will run down the walls. Since the rain will not stay on the chalk, it’s less likely to affect it.

The reason rainfall affects chalk paint is that chalk paint is a water-based paint. As such, the paint is water-soluble meaning that it will dissolve in water. So if the chalk paint is constantly exposed to rainfall, the paint will turn liquid and peel off the surface.

But you can reduce the effect of rain on the chalk by sealing the chalk paint with a waterproof sealant.

Can You Use Chalk Paint Outdoors?

You can use chalk paint outdoors. Chalk paint is great for outdoor furniture, walls, and objects. However, it’s generally advised to seal chalk paint that is used outdoors. This is to prevent the harsh exterior environment from damaging the paint.

Chalk paint is great for any type of surface including outdoor or exterior surfaces. But you shouldn’t use chalk paint on outdoor areas that aren’t protected or under a shed. This is because UV rays, light, and rainfall will affect the chalk paint making it peel off in the first few months.

If you are to use chalk paint on exposed outdoor furniture or material, you need to seal the chalk paint with a UV and moisture resistant sealant. But if you use the chalk paint on outdoor furniture that is protected or under a shed, you don’t need to seal the chalk paint. Remember, sealing the chalk paint is to make it last longer.

Related Read: Is Chalk Paint Durable?

Final Words

Overall, chalk paint isn’t waterproof but the paint can stand its ground if used in moist areas. As long as the moisture isn’t constantly hitting the chalk paint, then you are good to go.

But if the chalk paint is going to experience constant exposure to water or oils, it’s better to seal the chalk paint to protect the finish.

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