Can You Use Exterior Paint Inside?

Randy Charles
Professional Painter

Randy Charles is the owner of PaintCentric.com, a website dedicated to providing information, tips, tricks, and news about all things paint. With over 10 years...Read more

An average man believes all paints are the same. To some people, there are no differences between the ones used indoors and those used on building exteriors. There are different kinds of paint with different formulations that make them suitable for their specific purposes. Also, their high VOC content makes them very unsafe for indoor use.

So, can you use exterior paint inside? Exterior paints are not to be used indoors since their high VOC content makes them harmful to inhale. Furthermore, they lack the needed additives to withstand indoor conditions. To better understand what paints are suitable for different applications, we recommend that you continue reading.

What Are The Differences Between Interior And Exterior Paint?

Interior and exterior paints differ concerning several factors. Some contents present in one type of paint are absent in the other, while some contents present in one type of paint are entirely absent in the other. Lets read along as we consider the differences between these two paint types under the following categories.

Differences Between Interior And Exterior Paint

Durability

Both paints are built to be durable. However, you should expect more from exterior paints. Exterior paints are meant to withstand several harsh conditions such as rainfall, snow, and contact from stones or twigs thrown at walls. Exterior paints can withstand a direct hit without chipping off.

Interior paints are also built with contents that make them durable, but not as much as exterior paints. These paints will withstand occasional scrubs, scrapes, and abrasion from pieces of furniture and hands. You can expect them to come off easily if subjected to harder hits.

Amount of VOCs present

Volatile Organic compounds, commonly known as VOCs, are chemicals that are commonly used in formulating paints. These chemicals act as a medium of transfer between the paint can and the painted surface. It further aids the flow of paint on surfaces. These chemicals easily vaporize and would be a health hazard if inhaled for too long.

Exterior paints contain a higher amount of VOCs. These chemicals can be used outside without much risk as they can easily diffuse into the atmosphere without causing much harm to people around. On the other hand, interior paints have little need for this content because they are less subjected to conditions that require VOCs.

Adhesion

Both exterior and interior paints offer good adhesion on surfaces. However, exterior paints are richer in their adhesive content. This is because they are more exposed to conditions that can peel them off. On the flip side, interior paints have a smaller amount of adhesive present in them. Therefore, they offer good adhesion but are not as strong as exterior paints.

Pigment present

Exterior paints have a higher exposure to conditions that will make them easily fade. Common causative factors include rain and UV rays from sunlight. Thus, exterior paints contain organic pigments that provide better resistance to fading.

On the other hand, interior paints are not meant for such abuse. Thus, the amount of pigment contained in them isnt that much. Thus, they are more prone to fading if exposed to harsh or abusive weather conditions.

Additives present

This brings us to the content that is responsible for the major characteristics of different kinds of paints. Additives are substances added to paints, allowing them to withstand different conditions without suffering damage.

It also helps to prevent faults such as bubbles, flocculation, sedimentation, poor leveling, and more in the coating. Exterior paints are formulated with a higher content of additives. On the reverse, interior paints are less prone to endangering conditions and, thus, are formulated with fewer additives.

Resin content

Resins are substances that are contained in paints. This content is what determines the binding properties of different types of paint and how well paints will adhere to surfaces. While exterior paints use acrylic as resin, interior paints use silicone and epoxy. Acrylic resins are avoided in interior paints because of the harsh odors they generate.

Can You Use Exterior Paint Inside?

Paints have varying formulations. These formulations make them more suitable for the purpose for which they were designed. So, can you use exterior paint inside? While you can use this paint inside, we strongly advise that you dont.

Can You Use Exterior Paint Inside

This is mostly because they are formulated with contents that pose health hazards in enclosed places. One of the significant causes of this is the high VOC content present in them. Inhaling this chemical for too long can cause persons to feel ill even long after the paints have dried up. It also has odors that can make the interior of your home uncomfortable.

Benefits And Drawbacks Of Using Exterior Paint Inside

Benefits of using exterior paint inside

  1. They can help you reduce the cost of painting your house. This is especially when you’re low on money and still have other things you’re working on. However, we advise you to use exterior paint inside only if the space remaining is painted considerably small.
  2. They make good finishing on pieces of furniture. However, you must be mindful of letting the furniture stay outdoor for some time for the VOC content in the paint to reduce.

Drawbacks of using exterior paint inside

  1. The VOCs present in exterior paints emits harmful vapors. Even for months after they have been applied, these vapors are still emitted and are harmful to the body if inhaled for long periods.

This may result in a sick feeling for both the painter and the occupants of the house pets aren’t excluded either. In severe cases, this may lead to serious respiratory problems.

  1. Acrylic resins present in outdoor paints dont smell good. When used indoors, these exterior paints will give your house an unpleasant odor that may persist long after the paint has dried up.
  2. Many exterior paints tend to be oil-based and, most times, are flammable. The oil base used in this type of paint is to boost its resistance and resilience to harsh weather conditions. Storing these paints in your home can pose a fire risk, too, so be careful.
  3. Exterior paints are more expensive. This is because they come packed with heavy-duty additives to make them more resilient to the elements. They come with extra additives, pigments, and other chemicals to increase their durability.

Can You Mix Interior and Exterior House Paint?

You can mix interior and exterior house paint; however, note that the base must be the same. Mixing a water-based paint with an oil-based paint will result in a mixture you wish you didn’t create in the first place. The two paints won’t mix properly.

Can You Mix Interior And Exterior House Paint

Things You Should Consider When Mixing Interior And Exterior House Paint

  • If youre going to use the paint indoors, then you have to be mindful of the VOC content of the exterior paint. Therefore, we recommend that the ratio of interior paint to exterior paint is higher. Using a high percentage of outdoor house paint in the mixture can expose you and your family to the risks associated with inhaling excessive amounts of VOC fumes.
  • If you’re using such a mixture outside, make sure you have a higher percentage of outdoor paints present. This will help the mixture to have a higher chance of surviving the harsh conditions outside. Adding more interior paint to the mixture will cause the paint to fade or crack easily.
  • The kind of base used in the paints formulation is of utmost importance when mixing any kind of house paints. Only mix paints that have a common base. For example, oil-based paints should go together while water-based paints should be mixed together certainly not both. When you mix paints with two different bases, it results in a clumpy and uneven mixture.
  • You stand a risk of exposure to VOC fumes when handling exterior paints. So, we recommend that you mix the paints in a well-ventilated environment, or better still, do it outdoors. Also, we advise that you wear a protective covering over your nose to reduce the number of fumes you inhale.
  • Some chemical additives present in the paint could cause health problems to individuals with certain allergies. Therefore, we advise you to contact your physician if you encounter any health challenges due to the exposure.

Final Words

Can you use exterior paint inside? The disadvantages may not seem obvious at first, but you should never use exterior paint inside. This is because of the health risks the house occupants are exposed to due to the high VOC content of exterior paints. Also, exterior paints have acrylic resins that have an unpleasant odor and are best suitable outside.

If you must use exterior paint inside your house, we advise that you don’t stay in the house for 6 months. If you’re going to use a mixture of interior and exterior paints inside, you must ensure a higher percentage of interior paint in the mixture. This will help reduce the risk associated with the use of exterior paint inside.

Randy CharlesProfessional Painter

Randy Charles is the owner of PaintCentric.com, a website dedicated to providing information, tips, tricks, and news about all things paint. With over 10 years of experience in the painting industry, Randy has become an expert in the field and is passionate about helping others learn more about painting. He has written numerous articles on the subject and is committed to providing accurate and up-to-date information to his readers.

Leave a Comment

thirteen + ten =