Can You Use Exterior Paint Indoors? – Detailed Guide

Are you thinking of painting the interior of your home but are out of interior paint and are thinking of using exterior paint? It might sound helpful, but it is not a good idea.

Some people assume that exterior and interior paint are the same, but this is not true. Although they seem similar, they have many differences that make them unsuitable for use in other places. Below, we have discussed use of exterior paint indoors in detail!

Can You Use Exterior Paint Indoors?

Can You Use Exterior Paint Indoor

As exterior paints are exposed to the outside environment, they have chemicals that can tolerate intense sunlight and various weather conditions. Moreover, these chemicals prevent staining and fading by using UV protection.

Exterior paints are comparatively more pricey than interior paints. They also contain powerful pigment and resin to bind the elements together and reduce moisture. The following are the details of exterior and interior paint and if one can use exterior paint for the inside.

What Is Exterior Paint?

Before starting the comparison, the most significant thing is to have enough knowledge about exterior paint. You might know that exterior paint has reactive elements and binding agents that make it resist intense sunlight and prevent fading and staining.

Furthermore, they are expensive and easy to apply. A large amount of resin increases its durability and makes it resistant to mold and moisture.

Exterior paints are of two types, water-based and oil-based. Water-based paint dries fast and is comparatively more environmentally friendly. Moreover, it is easy to use and is yellow-resistant.

In contrast, oil-based paint takes much time to dry because of its viscosity and has more odor than water-based oil, which makes it less environmentally friendly. Exterior paint contains highly reactive elements that make breathing difficult if used indoors. If you’re planning to paint your roof, make sure to use roof coating sprayer.

What Is Interior Paint?

Interior paint is the best for use indoors. Many people use it for decorations in their homes. It is much more reliable than exterior paint indoors because it is environmentally friendly and more affordable. Moreover, it does not cause breathing problems because it contains fewer reactive elements and organic pigments. Though it has many uses, interior paint is not durable as exterior paint.

Interior paint is washable and can not stand various weather conditions. That is why it is not suitable for use on the exterior of a building. In addition, exterior paints are waterproof, but interior paint is not, which makes it fade over time. Various types of interior paint have less odor but do not show resistance to different things, such as molds, moisture, etc.

Also have a look at my article about best indoor paint sprayers

Using Exterior Paint As An Interior Paint

Although they have many similarities, using exterior paint inside is not a good idea. Many factors play a prominent role in making this paint unsuitable for the inside. The main common reason is that exterior paint is highly pigmented with reactive elements to prevent staining and fading. In contrast, interior paint does not contain highly reactive elements and has fewer binding agents.

As I stated earlier, the exterior paint has elements that can tolerate severe weather conditions, and interior paint lacks these elements because the inside of a building does not need such reactive elements.

In addition, the chemicals in the interior paint are much safer and more suitable for breathing than in the exterior paint. These are a few prominent reasons that make these paints unsuitable for each other. Let’s explore more differences between these paints.

Differences between Exterior Paint and Interior Paint

1. Pigments

Pigments play a prominent role in paint. They give stains and bind to resin to make it more durable and long-lasting. Now the question is how it may differ in interior and exterior paints.

Well, exterior paint uses more pigments for UV protection and to prevent fading. Moreover, the higher amount of pigments makes the color solid and durable. Due to the high amount of pigments, the exterior paint has more odor that can cause respiratory problems.

On the other hand, interior paint uses organic pigments that are more environmentally friendly. Furthermore, these pigments are transparent and give bright colors, but they are not as long-lasting as exterior paints.

In short, the stains in the interior paint make it less durable and can fade away after some time. The pigments in both paints play a prominent role in making them unsuitable for each other. You may also want to read about wood spray painting.

2. Binding Agents

A binding agent is also one of the prominent components of paint. The primary function of a binding agent is to hold the pigment and to protect the paint from staining and fading. Acrylic resin is the most popular binding agent in exterior paint. It plays an essential role in holding the paint’s components together. Although it has many uses in exterior paints, acrylic binding agents have a strong odor that makes it hard to breathe if used inside.

In contrast, interior paint also uses binding agents but does not have powerful chemicals or odor. As interior paint does not have to tolerate severe weather conditions or UV rays, it does not have powerful elements. Interior paint uses epoxy or silicone as a binding agent because they perform well and have less odor, making breathing easy.

3. Components

As I mentioned above, the exterior paint has to deal with various conditions. Therefore, It has components that increase its binding energy, make it stain-resistant, and protects against UV rays. The highly reactive elements in exterior paint play a prominent role in increasing its durability, providing solid stains, and much more. In short, exterior paint consists of numerous different components.

On the other hand, interior paint lacks many components. As I stated earlier, interior paint does not use highly reactive elements because it does not need them. Interior paint does not come with UV protection because it is not exposed to the outer environment.

Moreover, it consists of organic pigments and binding agents having less odor. Although both paints Seem similar, they use different components, making them non-interchangeable.

4. Durability

Durability is an essential factor in anything. People prefer using things that are more durable and long-lasting because everyone can not afford to buy the products after a few months. The same is the case with paints. Painting your house or room can cost a lot of money. Therefore, people look for more durable paint.

Although exterior and interior paints are durable, exterior paint is comparatively more durable than interior paint because it contains powerful binding agents. As exterior paint has to withstand various conditions, it has more pigments and resin to hold the color together and increase its durability. In contrast, interior paint is not durable as exterior paint because it lacks many powerful elements because of odor and respiratory problems.

5. Dry Time

As I stated earlier, there are two types of paint. Water-based paint dries quicker, while oil-based paint takes much time to dry. Moreover, oil-based paint is not easy to apply because of its viscosity. Many people use latex or acrylic paints for painting the exterior of a building because they are water-based and dry fast. In addition, sunlight plays a prominent role in drying the exterior paint more quickly.

In terms of interior paint, it takes more time than exterior paint because some interior paints are oil-based. Furthermore, interior paint does not have UV protection, so it starts fading when exposed to sunlight instead of drying. In short, exterior paint wins this race against interior paint because it dries quicker than interior paint.

6. Weather Resistance

Exterior paint must resist all weather conditions because it is exposed to the outer environment. If it does not withstand weather conditions, it will start fading. Therefore, exterior paint uses powerful binding agents and pigments to hold all elements together and to withstand various conditions, such as rain, snow, wind, thunder, etc.

On the other hand, interior paint also uses silicone and epoxy as binding agents, but they are not as powerful as acrylics. Moreover, interior paint uses organic pigments that are transparent and are not durable. Interior paint can fade away after some time because of the lack of various elements because they have more odor and cause breathing problems.

7. Temperature Resistance

Exterior paint must be temperature resistant because it has to withstand various temperatures. As I stated earlier, exterior paint can withstand intense sunlight and comes with UV protection. It can tolerate hot weather and cold weather. In short, exterior paint is temperature resistant and is more long-lasting and durable.

In contrast, interior paint does not have to withstand such intense weather conditions. Therefore, it is not temperature resistant. It is a little resistant to the temperature inside the building, but this resistance is smaller than in exterior paint. In short, exterior paint wine is the race against interior paint in temperature resistance.

8. Moisture Resistance

Another primary factor of exterior paint is the resistance against moisture. You might know that exterior paint has a large amount of resin, which makes it moisture-resistant. In other words, exterior paint is waterproof. If your paint is not waterproof, it will start fading and fail to withstand various weather conditions. Therefore, exterior paint is waterproof.

On the other hand, interior paint is washable to remove stains. It does not contain a large amount of resin to prevent more odor. Therefore, it is not waterproof or moisture-resistant. That is why interior paint does not last long and is unsuitable for the exterior of a building.

9. Fade Resistance

Another common factor of paint is that it should resist fading. If it is not resistant to fading, the stains will start to fade, and you will have to paint again after a few months. In some cases, paint that is not resistant to fading starts to get yellow. Therefore, exterior paint uses such elements that are fade and stain-resistant.

In contrast, interior paint also has some resistance against fading and stains, but this resistance is lower than in exterior paint. Exterior paint can withstand heat and sunlight, so it is fade-resistant, while interior paint does not withstand such conditions, so it is not fade-resistant. Interior paint can start fading after some time.

10. Price

Though exterior paint has many benefits and uses, it is a bit more expensive than many other paints. On the other hand, interior paint is more affordable than exterior paint. The price does not mean you can use interior paint outdoors or the other way around. Therefore, you must buy exterior paint for outdoors and interior paint for indoors.

FAQs about Exterior and Indoor Paints

What happens if you use exterior paint indoors?

I do not recommend using exterior paint indoors because it contains highly reactive elements that have a strong odor and can cause breathing problems. If you use exterior paint indoors, you will face breathing issues because of the smell. Moreover, some exterior paint is not safe for your health.

Is it OK to paint the inside with exterior paint?

It is not a good idea to paint the inside with exterior paint because you may suffer from health issues. Furthermore, interior paint is more reliable than exterior paint because it is affordable and environmentally friendly.

Is indoor paint waterproof?

Indoor paint is not waterproof. It does not come with a moisture resistance feature because it is washable and can remove various stains and marks. That is why it does not last long and is not as durable as exterior paint.

Is exterior paint more durable than interior paint?

Yes, exterior paint is more durable than interior paint because it consists of various elements that can withstand heat, sunlight, and different weather conditions. Moreover, it has a large amount of resin, which makes it waterproof and more durable than interior paint.

Is exterior paint thicker than interior?

Exterior paint is usually thicker than interior paint because of a large amount of binding agent. It uses acrylic as a binding agent because it holds the elements and the pigment together in a better way. Though it is thicker than interior paint, exterior paint dries more quickly than interior paint.

Concluding Painting Exterior Paint Indoors Guide

The above article consists of detailed information on the exterior and interior paints. Many people think both are interchangeable, but this is not true. Though they seem similar, they have many differences. Exterior paint can withstand heat and sunlight, while interior paint fails to do so.

Furthermore, interior paint is more affordable than exterior paint. Various types of paint have different dry times. Exterior paints dry quickly, and interior paint takes some time. If you use exterior paint indoors, you might smell the odor of reactive chemicals and face health issues.


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