Can You Chalk Paint an Exterior Door? (All You Need to Know)

Chalk paint is a great decorative wood paint that usually doesn’t require any prep work. You can paint straight over existing finishes as long as they are clean, and at the most, you only need a light sand. Chalk paint is often used for furniture, but can it be used on an exterior door? 

Yes, it can be used on your exterior door, but it depends on the weather in your area. Chalk paint is not fully waterproof so it will need to be sealed to protect it in wet climates.

This article will tell you everything you need to know about using chalk paint on exterior doors and how to protect it with a sealer. Make sure you read this before attempting to use chalk paint on your exterior doors.

Will Chalk Paint Last Long Outside?

Chalk paint is designed to be used indoors and outdoors, so it should last. However, there are a number of things that can damage the paint outdoors. UV rays, for example, will wear the paint down and water will quickly wash the paint away if it pools on the surface. If the water runs off the surface, it will take longer to damage it. So, if you paint a bench, it is more prone to water damage than a vertical surface like a door.

In a relatively dry climate, chalk paint will last a few years before it starts to wear and needs recoating. However, if you paint an exterior door and it is constantly lashed with rain, it won’t last as long unless you protect it somehow.

Is Chalk Paint Waterproof?

No, chalk paint is not fully waterproof, it is water resistant, and there is an important difference between the two. A waterproof paint is designed to stand up to a lot of water without getting damaged. Something that is water-resistant, on the other hand, can only deal with small amounts of water.

Take a watch, for example; if it is water-resistant, it won’t break if it gets rained on. But if you take it swimming, it will stop working because it is not fully waterproof.

The same is true of chalk paint. If used on a chair or table indoors, it will be fine if a bit of water gets spilled on it. But if you paint your exterior door with it and you don’t protect it in any way, the rain can seriously damage the paint.

Some chalk paints claim that they’re suitable for outdoor use and they are safe in the rain, but in my experience, they still won’t hold up for that long on their own, especially if you live in a wet climate.

Should You Seal Chalk Paint if Used Outside?

Yes, sealing chalk paint is the best way to increase its longevity. You can use a clear coat to protect the paint from moisture and UV damage, so you don’t have to keep reapplying it every few years.  There are a lot of different clear coats you can use but you need to be careful because some can turn slightly yellow when used on lighter colors.

Some also have a problem with yellowing or going chalky when exposed to the sun for a long period. You can find more information to help you choose the right clear coat in our guide here.

What’s the Best Clear Coat for Covering Chalk Paint On a Door?

Different clear coats have their own benefits and drawbacks but spar urethane is the best choice, in most cases. It doesn’t have anywhere near as many issues with yellowing that other clear coats do and it’s a very durable finish. It protects against moisture and UV damage, so it will keep your chalk paint in excellent condition for years to come. 

Water-based spar urethane products like this Minwax Helmsman Spar Urethane are perfect. It’s easy to apply and it gives you a durable satin finish that will last for years before it needs to be reapplied.

The Rust-Oleum Diamond Spar Urethane Stain is a good choice too. It’s designed for protecting boats from harsh saltwater, so it’s more than capable of protecting your exterior doors from a bit of rain.

Whatever brand you go for, always look for water-based spar urethane because it dries much faster and it doesn’t have the same pungent smell. You also get a nicer satin finish which looks better than the glossier look of the oil-based products.

How to Seal Chalk Paint Outdoors?

If you want to use chalk paint on your exterior door, or any outdoor furniture, follow these basic steps to seal it once it has fully dried.

1. Thinning Your Sealer

You don’t necessarily have to take this step, but if you are using spar urethane, it is beneficial. Spar urethane is quite thick and it can be tough to apply without brush marks. Thinning it with some water can help you get a much more even finish on your door.

To do this, add 10% of the volume of the spar urethane in water and mix it thoroughly. This will make it much easier to work with and help you avoid brush marks. If you want to use a sprayer, you can add more water until you have the right consistency (around 50% of the volume.)

Bear in mind that thinning it in this way may increase the time that it takes to dry as it has a higher water content.

2. Applying the First Coat of Sealer 

Using a sprayer will make the job easier and give you a nice even coverage, but a brush usually gives you the best finish. 

Sponge brushes are the best for applying spar urethane because you don’t have to worry about brush marks as much and you get a good coverage with each coat. Alternatively, you can use the wiping method; take a clean cotton cloth and wipe layers of the sealer onto the door. 

Regardless of the method that you use, you should always apply thin coats and let them dry between. Doing multiple thin coats will give you a nicer finish than slapping on thick coats that drip and look uneven.

Always work with the grain of the wood when applying the sealer, never against it.

3. Sand the First Coat

Once the first coat is completely dry, you need to sand it before applying the second coat. Sanding is important for a few reasons; it gets rid of small bubbles and brush marks and it also creates a better surface for the next coat to adhere to. 

Use a 220 grit fine sandpaper to gently sand the surface, then wipe with a damp cloth and let it dry.

4. Repeat 2-3 Times

Repeat this process 2-3 times to add more coats. Most exterior projects need at least 3 coats, but you can add more if you like. 

Once the last coat is finished, let it dry and leave it as it is. Make sure that you don’t sand the last coat because it will give it a dull appearance.

Final Thoughts

Chalk paint is great for your exterior doors because it’s so easy to use. You don’t need to worry about extensive preparation beforehand and it goes on very nicely. However, you do need to seal it to protect it against moisture and sunlight. Follow the steps listed above and you can make sure that you chalk paint stands up to the elements.