When it comes to home renovation, many people think they have it under control. Because of this, some don’t conduct the proper research. That led to botched painting jobs both inside and outside of their house.

The fact is, not all paints are created equal. The properties of interior painting are vastly different from those found on the exterior.

Whether your renovation is a DIY project or you hire a painting service, this is critical information to know. If you want to learn about the difference between interior and exterior painting, continue reading our helpful guide. 

Binding Resins

The job of binding resin is to help the paint adhere to the surface of your walls. Since exterior paint undergoes such harsh outdoor conditions, it needs a binding resin that is tough. Acrylic is usually the base resin found in exterior paint because it is durable and won’t wear away during extreme weather conditions.

Since acrylic can give off thick odors that may be hazardous inside, your interior paints stick to either silicone or epoxy resins. These are still durable, though. They can withstand things like scrubbing and cleaning with water without it tearing away. 


The ingredients used in either type of paint may vary. Surprisingly, most paints do not contain many different additives. However, they do possess additives to withstand several different situations.

For instance, exterior paints have to hold up against harsh sunlight. Because of this, there are ingredients added in to help divert the premature fading of your house color.

Exterior paints also have additives that help against debris and varying temperatures. Interior paints do not need such harsh additives because indoor conditions aren’t as severe. If you put interior paint on the outside of your house, you may see it fade or wear away much sooner. 


The first thing we look at when it comes to painting is the pigment or color. We all want our houses to look their best and with a vibrant new coat of paint.

To ensure your paint job comes out looking perfect, you should know that pigments for exterior paints differ from those you would use indoors. Indoor paint solutions are typically organic.

Their pigments are brighter and contain fewer fumes. Those used for the exterior of houses contain non-organic chemicals because the paint needs to remain durable and fade-resistant. Plus, the colors for outdoors may offer you a smaller selection of colors. 

Weather and Physical Damage

As mentioned, exterior paints undergo harsh weather conditions. Being on the outside of your house means exposure to things like:

  • Rain
  • Thunderstorms
  • Wind
  • Sleet
  • Snow
  • Hail

Depending on your location and what weather your area experiences the most, you need paint with the best durability and resistance to weather. Interior paints do not have these additives, so they are liable to chip and break off if you are in severe thunderstorms or hurricanes.

Along with the weather, exterior paints can take a substantial amount of physical damage. For instance, even the slightest breeze can cause erosion if it is constant enough.

Along with that, physical damage also entails sticks, bugs, and dirt flying into the sides of your home. Sturdy exterior paint should take years of weather and natural damage before it even begins to show on the surface of your home. 

VOC Levels

Volatile organic compounds may create short or long-term health effects if individuals expose themselves for too long. Since exterior paints have more durable binding resins and additives, volatile organic compounds are present at higher rates.

Typically, this is not a problem when painting outside in the open air. The wind is usually enough to blow the toxic fumes away from the person. So, they do not inhale an unhealthy amount.

However, if you use exterior paint inside, you could expose yourself and others to these chemicals. Interior paints do not have the same levels of VOCs.

Since this paint is for indoor use, the fumes are little to none. You can even find paints that have no fumes at all and do not emit VOCs. That said, you should still open a window while painting inside just for safe measure. 

Time to Dry

Several factors add to the drying time of each type of paint. Paint for exterior use is usually water-based.

Because of that, the paint will dry faster than indoor paint would. The sunlight, wind, and heat also play a factor in drying the outside of your house. Since interior paint does not withstand outside elements or constant airflow, it will dry slower. 


Exterior paint contains additives that help it hold up under hours of direct sunlight and heat. It also has properties to protect it from harmful UV rays that disrupt chemical bonds and cause fading.

Since interior paint does not undergo exposure to sunlight, the protective additives are not present in the solution. Therefore, if you use indoor paint on the outside of your house, it may fade faster. 

Mildew Prevention

If you are painting inside, then the solution you have probably does not contain mildewcides. However, one of the additives in exterior painting is a mildewcide that prevents mildew and mold from forming on the exterior of the house. These elements are not only harmful to your health but can eat away at paint if the proper protection is not present. 

More On Interior and Exterior Painting

As you can tell, there are several differences between indoor and outdoor painting. You cannot use paint meant for the inside of your house on the outside because it is not waterproof or oil-based.

Likewise, using exterior paint on the inside may not result in the correct pigment or tone. We hope this article helps you better understand the differences between interior and exterior painting.If you require professional aid, the Brush Masters are here to help. Feel free to contact us and request a free estimate. We will make one up for you soon as possible so we can get to painting your house the color of your dreams.