No, chalk paint isn’t waterproof, the paint has minimal water-resistance qualities and will get removed if exposed to constant water or rainfall.
To make chalk paint waterproof, clean and sand it, apply a waterproof sealer, and test the waterproof qualities of the finish.
Is Chalk Paint Water-resistant?
Chalk paint has a low level of water resistance. The paint washes off if exposed to constant water as it doesn’t contain protective additives that make its coating withstand water.
Chalk paint is water-based, meaning its resins are dissolved in water — so if you add more water to its finish, the resins (or binders) will dissolve and the finish will get removed.
The paint doesn’t have a glossy finish that repels liquids, instead, it has a dry textured finish that accumulates water and dust. Since water doesn’t slide off the finish, it will stay over it until it penetrates the coating or evaporates.
You can clean (or wash) chalk paint finish with water as it has a low level of water resistance and will withstand water for a short period of time without getting removed.
How To Make Chalk Paint Waterproof?
To make chalk paint waterproof, do the following things.
- Clean and Sand the Chalk Paint.
- Apply a Waterproof Sealer.
- Test the Waterproof Qualities of the Finish.
The tools you need for this project are listed below.
- Fine-grit sandpaper
- A paintbrush
- A waterproof sealer
- Clean rags
1. Clean and Sand the Chalk Paint
Clean the chalk paint finish with a dampened rag to remove dust, filth, and dirt that can prevent the sealer from adhering.
If you don’t remove the dust, filth, or dirt from the chalk paint finish, they will show once the sealer dries. Most sealers are colorless (transparent) and will highlight imperfections once dry.
Sand the chalk paint finish with fine-grit sandpaper (220-grit) to remove imperfections and create tiny holes (pores) in the surface that the sealer can penetrate. Sanding will improve the adhesion between the paint finish and sealer coating and help to achieve a smooth and flat finish.
Re-clean the surface after sanding to remove dust.
2. Apply a Waterproof Sealer
To apply a waterproof sealer, do the following things.
- Prep the sealer (thin, mix, or shake it) based on the manufacturer’s instructions.
- Apply three (3) waterproof sealer coats with a paintbrush or sprayer.
- Wait until one coat dries before applying the next one.
- Optionally, sand between sealer coats.
- Wait until the last sealer coat cures (fully dries) before using the surface.
You must use a waterproof sealer that is compatible with chalk paint and designed for exterior use. Waterproof exterior sealers are formulated with extra protective additives and UV-blockers that will withstand outdoor weather elements and protect the paint and surface.
3. Test the Waterproof Qualities of the Finish
To test if the paint finish is waterproof or not, do the following things.
- Pour a small amount of water over the paint finish coating.
- Wait a few minutes.
- If the water soaks into the coating or takes the paint color, the finish isn’t waterproof.
- If the water has a clear color and doesn’t penetrate the finish (stay over it), the finish is waterproof.
Can You Use Chalk Paint Outdoors?
You can’t use chalk paint outdoors as the paint isn’t waterproof or formulated with protective additives that make its finish withstand outdoor weather elements.
Unsealed chalk paint lasts about 1 month outdoors if exposed to constant water or rainfall. Rainfall and dust will damage the chalk paint finish and quickly remove it off the surface.
Seal chalk paint with a water-resistant or waterproof sealer if you want to apply it outdoors. A water-resistant or waterproof sealer will produce a glossy transparent coating over the paint and protect it from water, moisture, and scratches.
Sealed outdoor chalk paint will last about 3 years outdoors, depending on the type of sealer you use. Touching up the sealer coating every few years will make the paint last longer.
Does Rain Remove Chalk Paint?
Rain does remove unsealed chalk paint as the paint has a low level of water resistance and can withstand water only for a limited time.
Rain affects chalk paint on horizontal surfaces more than on vertical surfaces because the water (or rain) stays on horizontal surfaces until it evaporates or penetrates the paint as it can’t slide off.
Rain on vertical surfaces, such as walls, will slide off and won’t damage the paint finish as much.
Seal the chalk paint with a water-resistant or waterproof sealer to make it withstand rainfall or use it outdoors.
Related Read: Is Chalk Paint Durable?