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What’s The Difference Between Interior and Exterior Paint?

Several tins of paint for article difference between interior and exterior paint

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Different types of paint are created for several different purposes, and each has its own set of characteristics. For example, interior paint will be used when painting your interior doors, cabinets, baseboards, and exterior paint would be preferred when painting your garage doors, or shutters.

When it comes to exterior paint, mildew and fading are no match for its composition. On the other hand, interior paint is simple to clean and stain-resistant.

To identify between different types of paint, one must first get familiar with the chemistry of each kind of paint. Take a look at the two types and note how they differ from one another in terms of specifics.

So, continue reading our article to delve deeper into the difference between interior and exterior paint.

What Is Exterior Paint Used For?

Adhesives in exterior paint make it resistant to the elements, making it ideal for painting the exteriors of many types of structures. Rain, snow, sleet, and any other kind of precipitation are no match for it.

It’s also Ultraviolet Resistant, so you won’t have to worry about it fading or breaking over time. Additionally, it is built to withstand wind-blown twigs and other debris, preventing chipping and flaking.

Extra resins and additives, such as Volatile Organic Compounds, are included in the formulation to provide a longer-lasting paint.

While the paint is drying, this will cause outgassing. Most of the gasses will be released in a few days but can continue to be released for several years. In addition to preventing mold and mildew, the use of Mildewcides is also recommended. If inhaled, these can cause respiratory problems.

?Key Insight: Are you trying to determine if exterior paint can be used inside? Well, we have just the article for you, but be wary of the Volatile Organic Compounds released from exterior paint!

What Is Interior Paint Used For?

Four five gallon cans of paint, for article difference between interior and exterior paint

This kind of paint is used for decorating your home’s ceilings or IKEA furniture and aesthetics. As a result, interior paint provides features such as moisture avoidance, washability, and ease of upkeep at the same time.

This kind of paint is designed to endure abrasion, making it ideal for the inside of your home. For this reason, it’s made to be more delicate than exterior paint since it’s in the same room as humans all day.

Stain-resistant and scrubbable, this paint is a great option. Due to its lack of exposure to sunshine, it is not fade-resistant.

Interior paints are formulated to simply remove smudges and smears from dogs and children using a simple cleaning solution.

Unlike their exterior counterpart, low or no VOCs are used to manufacture interior paint. Therefore, maintaining good indoor air quality is much easier when using interior paints.

The Difference Between Interior and Exterior Paint

Having reviewed the fundamentals, let’s now look at the difference between interior and exterior paint

1. Binding Resin Types

The strength of the paint’s adhesion to a surface is determined by the glue used to attach it. Acrylic is the binding resin used in exterior paints because of its exceptional strength and long-term durability.

On the other hand, acrylic has a strong odor; hence, epoxy and silicone are used instead in interior painting.

2. Pigments

You may have heard that color is created by pigments. When it comes to paints for the interior, organic pigments are used.

It’s safe to breathe them in since they don’t have any strong aromas or fumes. Non-organic pigments in exterior paints may worsen strong scents and fumes, but they don’t fade as rapidly.

This is because exterior paints require durability more than they need to keep out harsh chemicals.

3. Various Additives

There are fewer ingredients in interior paints than exterior paints because of the fewer hazardous environments they must contend with.

A wide range of environmental factors must be considered when developing exterior paints.

This is why extra compounds are employed to resist paint fading, cope with temperature shifts, and even prevent cracking if needed. Exterior paints may also include mildew-, mold-, and algae-preventing mildewcides.

4. Weather-Resistance

Heavy rain hitting against a house

Interior paints aren’t designed to withstand extreme temperatures or unpredictable weather. Consequently, their temperature and water resistance are both relatively poor, and they fade fast in the sun because of this.

Exterior paint may tolerate a wide range of temperatures as it must withstand both the cold and the heat.

?Key Insight: Most people’s houses have a temperature range of 60 to 90 degrees Fahrenheit, where interior paint is designed to be used.

5. Durability

Exterior paint is designed to survive the elements for many years, unlike interior paint. In terms of protecting your home, exterior paints can withstand twigs and bugs blowing into the wall from the wind.

 So, it’s a lot more long-lasting than interior paint. On the other hand, a little washing and cleaning will not harm interior paint.

6. Physical Damage Resistance

Your interior paint may chip off if it receives a direct blow, revealing the previous paint or bare wall behind it.

Chipping outside paint is significantly more difficult since the resins that hold the surface color are much more substantial.

7. VOC concentrations in the air

To put it simply, VOCs are volatile organic compounds, and inhaling them may be dangerous.

Fortunately, interior paints have a shallow VOC content. Painting the outside of your home, on the other hand, does not fall under this category.

Since exterior paints are not meant to be used inside, they frequently contain a high concentration of volatile organic compounds (VOCs).

When it comes to exterior paints, this may make them more weather-resistant and durable, but it also means that they will emit harmful gasses as they dry.

?Bear in Mind: If you use exterior paints inside, the fumes can pose serious health complications, but always be sure to use protective equipment such as masks, goggles, and gloves!

8. Adhesion

The adherence to both interior and external paints is excellent. On the other hand, exterior paints adhere so well that they can survive bad weather.

Generally speaking, exterior paints are more durable and stickier than inside paints.

9. Dry time

Paints with an oil base dry more slowly than paints with a water base. However, paintings left outdoors in the sun will dry more quickly than paints left in a room with no air circulation.

Finally, the paint will dry quicker if it is heated. In general, outdoor water-based paint dries faster when all these conditions are present.

10. Fade resistance

Sunlight is one of the most continuous external elements your paint must deal with. Most days of the year, the sun will shine down on it for at least 12 hours.

Fortunately, exterior paint additives are designed to withstand this fading and even defend against UV rays, so you don’t have to worry.

Indirect sunshine, on the other hand, will fade interior paint. There are no extra ingredients to prevent the fading of organic pigments in interior paint.

11. Resistance to Water Absorption

Faded paint on a wall mainly caused by damage from harsh weather conditions

In most regions, rainstorms, thunderstorms, and even simple showers are an everyday occurrence; so exterior paint must endure these conditions and more.

Occasional cleaning of inside paint is required for it to last. As a result, exterior paint is far more water-resistant.

12. Preventing Mildew Growth

There are no mildewcides in most interior paints. Algae, mold, and mildew are significant risks to your home’s exterior.

?Definition: Mildewcides are applied to exterior paints to prevent mold growth.

Even though they aren’t ideal for your health, they do an excellent job of deterring mold, mildew, and algae growth.

13. Resistance to Scratching and Rubbing

Interior and exterior paints are equally scratch-resistant. However, exterior paint’s long-term durability ultimately prevails. It can tolerate far more scuffing with minimal harm.

14. Cost

Even though the price difference between these two kinds of paint isn’t huge, it exists nonetheless. Because exterior paint is more durable and contains more additives and chemicals, it tends to be more costly.

Interior paint is less expensive of the two, but it doesn’t provide the same protection and durability.

When you’ve Already Used Interior Paint Outside:

Using interior paint on an outside surface, such as vinyl soft sheen paints, may cause various issues. You’ll see right away that the paint itself may not be able to cling to the surface.

Interior paints are often too thin for outside surfaces, such as stone or concrete. These paints may take many applications to achieve even a thin covering.

It may also take a long time for these paints to dry. They will not dry in moist or icy circumstances in many situations.

As previously mentioned, paints for the inside do not have the same additives as paints for the outside. For example, they will not be immune to the impacts of the weather.

Rain, frost, and other types of severe weather may cause peeling, running, and cracking paint, among other problems. Overexposure to the sun may cause a variety of significant health issues in certain people.

When You’ve Already Used Exterior Paint Inside

External paints are meant to withstand the impacts of the elements, but they are not intended for use indoors. When used internally, they are easily marked and scuffed.

Just because exterior paints can tolerate severe weather conditions, they can not withstand frequent usage or footfall, and they’re less likely to entirely cover the ceiling, wall, or floor.

Some exterior paints emit potentially toxic vapors that dissipate when exposed to the elements. However, these vapors might get trapped when employed within a structure, resulting in disagreeable odors.

For my key reasons as to why you should not use exterior paints indoors, we have an ideal article for you.


What is the best exterior paint?

Oil-based and water-based paints are the two most common varieties. Oil-based paints are well-suited for outdoor painting since they are carefully designed with ingredients that give them endurance.

They contain alkyd, which is good for repelling dirt and managing temperature and humidity changes.

What is VOC (volatile organic compound) in paints?

Volatile Organic Compounds (VOCs) are chemical solvents used as a medium in various water-based coatings and paints to enable the paint to flow. The EPA recommends that VOCs be used sparingly in interior paints since they may create health problems.

Is it possible to apply interior paint outdoors?

Because interior paints lack the ingredients needed to endure the weather, they should not be used outdoors. Furthermore, interior paint is thinner than exterior paint, so it doesn’t adhere as well to outside surfaces, and you’d have to apply multiple coats to attain the same coverage.

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