There are loads of different paint types on the market today, each with its own set of qualities. These two basic categories are exterior paints for durability in a harsh environment and interior paints to keep your home looking its best.
So, what is the difference between interior and exterior paint? Exterior paint is weather, fade, and mildew resistant. Interior paints are formulated to be cleanable and designed not to stain the painter. Interior paint can be water-based, which makes it easier for cleanup, while exterior paints have oil bases for extra protection against mold.
In this article, we’ll explore how these products differ, what their characteristics are, and whether you can use them interchangeably.
Understanding The Basics Of Paint
All paints are composed of the same ingredients – resins, additives, and pigments. Solvent is what makes paint wet. The paint will dry out over time as air evaporates its moisture content.
Pigments are comprised of tiny molecules that give the paint its color. Special additives can give your paint varying physical effects, like water or UV resistance, to make it more durable. When you apply the final coat of paint on your project, solvents will quickly start evaporating from the painting’s texture as soon as they dry up.
The resin binds all these components together, but they can differ depending on whether you’re looking at silicone, acrylic, or epoxy-based products. All these types have their benefits, such as ease of application versus durability, respectively.
In both the exterior and interior paint, there are similarities between pigments and solvents. For outdoor painting, oil-based or water-based paint is a good choice. However, oil-based paints are not recommended for interior paints because of their odor. They are also more challenging to clean.
Exterior Paint
Meant for painting the outer walls of buildings, exterior paint contains additives that make it weatherproof. It can withstand rain, snow, sleet, and almost anything else nature has to throw at it. Plus, it’s built to handle years of hard sunlight without fading or cracking.
It’s also very durable to avoid chipping and flaking when the wind blows twigs and other debris against your home. To make a more durable exterior paint, manufacturers use higher quality resins and additives that cause off-gassing while the paint dries.
Most of this outgassing will happen just days after application, but it’ll continue slowly for up to several years. Mildewcides are also used to prevent mold and mildew, which can lead to respiratory issues if inhaled.
Properties Of Exterior Paint:
- Exposed to various weather conditions, this paint is specially designed to withstand the elements. It protects the building from moisture, snow, and sunlight. This includes protection against fungal growth on surfaces such as wood or concrete exposed to water or high humidity levels.
- Exterior paints are also made to combat mold and mildew. Since they face UV radiation, they also need to be fade-resistant for durability.
- Exterior paints are flexible because the type of resin used in making them is soft. As a result, they do not crack on contraction and expansion. This also makes them more durable against the effects of moisture and temperature changes.
- You can apply exterior paint to various substances just by changing the sheen. A house’s exterior absorbs water during rain. Flat paint won’t bubble, and it’ll allow the moisture to escape through a porous surface so that no puddles form on your roof or in your basement.
- It’s well known that exterior paint is not recommended for indoor use because it releases volatile organic compounds when wet and needs sunlight to cure.
Interior Paint
Interior paint is meant to color the inside of your home. Although it’s not as durable as exterior paint, it can withstand occasional scrubbing and washing. It isn’t waterproof, nor can it withstand weather conditions or sun.
Furthermore, interior paint is low in harmful chemicals such as VOCs and other toxins. You don’t have to worry about harsh, toxic smells either because there are few to no outgassing fumes when using it indoors.
This means you can paint the walls without worrying too much about your health. That being said, interior paints tend not to be very durable for several reasons. For instance, direct sunlight will cause organic pigments used on interior paint to fade quickly. At the same time, they also crack more easily than exterior ones, which makes them less attractive over time.
Properties of Interior Paint
- Painting the interior of your home can be a great way to make it more beautiful and adds benefits like preventing dampness and decreasing maintenance.
- Interior paint is formulated to withstand abrasion. As it occupies the same space as people, when they are moving around on its surface and touching things with their hands or wiping up spills, it also has to be durable.
- As it’s so versatile, this type of paint can be used to cover up any blemishes on a building. It also resists staining and washes off easily with water or scrubbing without fading away as other glossy paints do in the sun.
- Choosing a washable interior paint is excellent for those of you with little ones and pets. Roller marks, crayon, pet paw prints – they all come off easy peasy.
- When looking for new interior paint, make sure it is lead-free and has low amounts of volatile organic compounds. This helps reduce your health risk and is crucial to preserving the air quality in your home.
Are Outdoor And Indoor Paints Interchangeable?
In short, no. These two paint types have different properties, which make them suitable for separate purposes. Interior paints typically have higher levels of pigment that can withstand normal wear and tear and furniture that is constantly being moved or shifted for a new look (changing the color scheme).
However, exterior paint should be more water-resistant than interior because it’s outside in environmental conditions such as heat, sunlight, wind, and rain. This, along with gloss finishes, makes it durable against deterioration in the long term.
Another reason why you can’t use them interchangeably is that after the application of exterior paint, there is a possibility that there will be outgassing. This process usually lasts for no more than two days but can continue with smaller amounts for years to come.
Therefore, if used indoors, this could cause headaches and nausea from gasses which are packing heat-insulating chemicals known as VOCs (volatile organic compounds).
For stucco and masonry, you should use flat sheen exterior paint. These let surfaces breathe by allowing moisture to escape through the finish coat and brick walls where water vapor needs to evaporate from inside or outside, respectively.
In the case of interior paints, these are not made to withstand weather conditions. And if you used it on the exterior walls or a surface exposed to the outer atmosphere, it won’t last for longer than a few months. Hence, all your painting effort will go into the trash.
Apart from this, there are disadvantages to universal paints that make them less desirable than other types, such as water-based or oil-based paints. There’s more work involved in prepping for outside painting because they don’t clean up with soap and water as acrylics do. You might be required to use solvents, which make cleanup even harder.
Wrapping Up
So, if you’re planning to paint your house, you need to figure out what your needs are before choosing a type of paint. Interior and exterior paints are created differently, so it’s essential to know the differences before deciding on them. With distinct functions of each type of paint, you cannot use interior and exterior paint in place of each other.
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