What’s The Difference Between Exterior And Interior Paint?

What is the difference between exterior and interior paint? We will answer this question clearly in this article.

Painting your room or your home is always an exciting but mind-boggling task. No matter the occasion, there is no perfect timing to paint your house.

Difference Between Exterior And Interior Paint

You can do it anytime you like. But, the real task comes when you make a trip to the paint store. Which paint texture should you use? Can you use the interior paints for your exterior too?

The answer is a straight No! The different kinds of paints are not created in the same way, and depending on what you wish to paint, you need to choose the paint accordingly.

All paints have different properties, depending on their intended use. For example, interior paints are designed to enable scrubbing, allow regular cleaning, etc. while exterior paints are made to protect against mildew, fading, and so on.

Any kind of paint is made up of four basic ingredients- resin, additives, solvent, and pigment. The kind of pigment and solvent are more or less similar for both the paints. What differentiates the two more are the additives and the resin used.

There is an absence of environment-specific additives in paints, which makes interior paints unsuitable to be used on external surfaces.

Regardless of the type of paint you want, given below are the three important things you should remember while purchasing paint:

  • The quality of paint can depend on the price. You should look into the length and breadth of an area the paint will cover.
  • For exterior surfaces, using the best paint grades will give the best durability.
  • Color and paint gloss will fade off with time, especially in areas that are exposed to sunlight.

What are the differences between the two types of paints?

1. Pigment

Pigments are components that give a particular color to paint. In the case of interior paints, the kind of pigments used is organic. Some kinds of organic pigments are known to fade away when used as exterior paint. Organic pigments are hence not used in exterior paints.

The kind of pigments used in exterior paints should be able to combat adverse environmental conditions.

2. Binders

Binders are kind of additives used in paints, meant to bind the pigments together. The presence of binders also provides more adhesion to the painted surface.

Exterior paints are specially designed to resist harsh environmental conditions such as rain, snow, UV rays, changes in temperature, dust, and many other things.

The binders used in exterior paints give resistance to cracking or chalking and also helps in controlling moisture.

While for interior paints, the binders used will provide more resistance to abrasion, which is not much of a necessary quality in exterior paints.

3. Types of Liquids used

The types of liquids used also differs for both the paints. One of the solvents used as a liquid in paints is VOCs ( Volatile Organic Compounds).

VOC’s can easily vaporize at room temperate, and the presence of VOC in the air has been linked to both short ( dizziness, headache)and long term ( liver damage, respiratory diseases)health problems.

According to Federal guidelines, interior water-based paints, even those that include latex, are specially designed to contain the lowest levels of VOCs.This guideline is not followed for all exterior paints.   

According to the Environment Protection Agency(EPA) reports, the level of VOCs inside the house is estimated to be three or five times higher as compared to the exterior. This level can also increase after painting.

When searching for an interior paint, make sure to go for low-to-no levels of VOC. This is one of the main reasons why exterior paints shouldn’t be used for interiors.

Some homeowners may feel that exterior paints, when used indoors, will be more durable, but that is a completely wrong idea. Surprisingly, exterior paints are known to be more prone to scratches and abrasions.

Along with that, the fungicides and the mildewcides used in exterior paints can cause allergies or release bad odor on humid days when used indoors.

Which paint to use where?

Now that you have an idea of the differences between the two paints, here is a list of which paint should be used where.

  • First thing, exterior paint should never be used indoors. It can cause tremendous outgassing, which means an increase in the amount of gas or vapor inside the house.

As mentioned above, the outgassing of VOCs can be detrimental to you and your family’s health.

  • If you wish to paint furniture for outdoor purposes, make sure that the furniture is painted outdoors and not inside. Doing so will allow the VOCs to escape.
  • In the case of interior paints, it is best to opt for oil-based paints, since they are more resistant to stains and can be scrubbed easily.
  • If you are planning on painting a masonry or a stucco, it is advised to use exterior paint. The main reason being, using flat paint will allow rainwater to wash off from the surfaces easily.
  • Semi-glossy paints work best for painting metals or things that are prone to constant touching. This will make the surface resistant to both abrasions as well as any wear and tear or from the absorption of water from the surfaces.

Conclusion

Paints are made up of different components, but each component has a role to play for the purpose of the paint. Most people don’t know the real difference between interior and exterior paints.

Now you know how different the two paints are, it will be easier for you to go to the store and ask for what you want exactly.

In the beginning, both these paints may appear to be similar, but only when you closely understand the specifications will you understand the intricate differences between the two. It is never a good idea to use exterior paint for interior use or vice versa.

It is important to always check the tin in order to understand the key components in the paint and buy the one that best serves your purpose.

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