Painting is a great way to breathe new life into your home. For the most part, this is a simple process, but it’s still important you choose the right type of paint.
Whether you have an extra can of exterior paint taking up space in the garage or wish to paint your home interior the same color as its exterior. You may be wondering if you can use exterior paint inside.
In this article, we will look at the difference between interior and exterior paint and when it’s possible to use one in the stead of the other.
Can You Use Exterior Paint Inside?
Technically, you can use exterior paint inside, but this is not recommended. Interior and exterior paints have different formulas and are meant for specific environments. Using exterior paint indoors usually comes with potential health risks due to the high level of VOCs in the paint.
What Is Exterior Paint
As the name suggests, exterior paints are paints formulated for use on outdoor surfaces. They typically use resin binders and a blend of additives to withstand the blistering sun, heavy downpours, and other extreme temperature changes.
Most exterior paint is oil-based and thus contains a high amount of VOCs (volatile organic compounds), which makes them unsafe when inhaled over a long period. They are typically mold-resistant and can last up to 7-10 years when correctly applied.
What Is Exterior Paint Used For?
As the name suggests, exterior paint is used for outdoor projects. In fact, it should never be used indoors unless it’s an indoor/outdoor paint.
Ideally, a good exterior paint should offer protection against the elements. It should be versatile enough to withstand the rain and harmful U.V. rays. It should also inhibit the growth of mold and mildew and, in some cases, offer protection against rust.
Most exterior paints are also known not to crack, peel, or fade easily.
What is the difference between exterior and interior paint?
The main difference between interior and exterior paint can be seen in the composition. Exterior paints usually contain a higher amount of VOCs, which is why they are unsafe for indoor use. This includes both regular paint and primer. Interior paints, on the other hand, emit minimal VOCs and are usually water-soluble.
As a result, exterior paints are usually more durable and can withstand harsh weather conditions such as snow, rain, sun rays, mildew, and other harsh conditions.
Other differences are highlighted below:
Interior Paint.
- Dries quickly and doesn’t require sunlight to dry.
- Easy to clean with water.
- Fades and peels more easily.
- More stain resistant.
Exterior Paint.
- Requires sunlight to dry properly.
- More difficult to clean and often requires solvent.
- Offer more protection from U.V rays.
- Highly resistant to fading, cracking, and peeling.
Why do people choose to use exterior paint inside their homes?
Since exterior paint is resistant to mold, moisture, U.V. light, and harsh weather, it seems to be perfect for anything. But this is not always the case.
1. Extra durability
Most people use the paint indoors because of the extra durability. But is this really required? Well, the answer is NO.
When painting interior surfaces, what you often need is a paint that is resistant to stains and is easy to clean.
2. Semi-interior areas
There are a few exceptions where it may be possible to use exterior paint indoors. For instance, there are some parts of the home that share both indoor and outdoor elements.
In most cases, people rarely stay in these areas for long periods. An example is a shed, a pool storage room, or a detached garage. Since these areas are rarely occupied, you can paint them with exterior paint without putting anyone at risk of inhaling harmful fumes for long periods.
3. Moisture Prone Areas
Some people may also use exterior paint in areas of their homes that are constantly exposed to moisture and mildew. Examples of such places are your bathroom, basement, and kitchen.
However, we only recommend going this route if you plan to leave the house for long periods. Also, ensure the space is well-ventilated to reduce the impact of the VOCs. For kitchen environment, ensure you use food safe paints to prevent ingestion of harmful chemicals.
Is It Safe to Use Exterior Paint Indoors?
No, it’s not. The problem with using exterior paint indoors is that most products contain high levels of VOCs, which, when inhaled over long periods, can cause many health problems.
Some common symptoms of VOC exposure:
- Nausea
- Loss of coordination
- Eye, lung, or nose irritation.
- Problem with vision.
- Headache and dizziness.
- Damage to the nasal passage and airways.
- Complications with the central nervous system.
Some paints may be designed for both indoor and outdoor use. Even in such cases, it’s best to move the project outside and take it in after it has fully cured.
Can You Use Exterior Latex Paint Inside
Yes, you can use water-based latex paint on interior walls. While it may not be as durable as oil-based, it emits fewer VOCs, making it safer to use.
In addition, latex paint is low odor and easier to clean, which is great in case you have to deal with a mess. It also dries faster and is non-yellowing.
As earlier indicated, you can only use water-based or exterior acrylic latex paint. Ideally, it should be targeted toward interior and exterior surfaces. Avoid oil-based or chemical-based products by all means.
Can You Use Sherwin-Williams Exterior Paint Inside
This depends on the composition. If the paint is exclusively for outdoor use, then it’s best not to use it indoors. There are a number of Sherwin-Williams paints that are designed for both interior and exterior surfaces; you might want to opt for such products.
Sherwin Williams paints are generally low VOC, which makes them versatile and suitable for many applications.
Can You Use Behr Exterior Paint Inside
As Sherwin-Williams paints, Behr paints are usually safe to use and have fewer VOCs. There are even products with zero VOC; these are usually their interior paint. In most cases, they offer exterior paints that can be used indoors. But to be on the safe side, make sure it’s clearly written on the label that you can use the paint indoors.
Things To Consider Before Using Exterior Paint Inside
- VOC Levels.
- Flammability.
- Application.
So, what are those things to consider when using exterior paint indoors? Let’s look at the main ones:
1. VOC Level
The main reason why exterior paints are not suitable for indoor use is due to the high levels of VOCs in the paint. However, not all exterior paints are the same. While the majority are high in VOCs, there are still a few that contain a lower amount of VOC and are less harmful. Acrylic and water-based paint usually have the least amount of VOCs, while oil-based paints have the highest.
If you must use any exterior paint indoors, you have to make sure it’s low VOC, and there’s plenty of ventilation in the space. Also, it should be clearly stated on the can that you can use it indoors.
2. Flammability
Oil-based paints are usually more flammable than interior paint, making them unsuitable for interior surfaces, especially in areas exposed to heat. Unfortunately, the majority of exterior paints are oil-based.
Having said that, paints are not usually responsible for house fires. But it’s always a good idea to ensure the safety of your home by not using substances that could potentially cause a fire.
3. Application
While most exterior paints are specifically designed for outdoor use, there are still a few that can be used indoors and outdoors. These products are usually described as “indoor/outdoor” paint. This means you can use the paint indoors. However, you need to ensure there’s a lot of ventilation in the space.
What Do I Do If I Accidentally Used Exterior Paint Inside?
We already know that it’s not a good idea to use exterior paint inside. But what if you mistakenly did? What can you do?
Well, you don’t need to worry too much, and it is not an immediate danger if you have good ventilation.
Here’s what you need to do:
1. Increase ventilation
As earlier indicated, with good ventilation, the impact of the paint fumes will be greatly reduced. Open all the windows if you haven’t done so already, and turn on the fans. This will quickly increase airflow in the space to direct the fumes outside and get rid of the smell faster. Make sure there are no kids and pets around.
2. Vacate the area
It’s best to leave the area once you’ve done everything to improve the ventilation. You want to limit your exposure to the fumes and toxins. In fact, leaving the space will also help with ventilation, which will speed up the drying process.
If possible, vacate the building. Once again, make sure there’s no one in the room.
3. Repaint the area
The best solution is to remove the paint or prime it and repaint it again.
If you decide to remove the paint, use a paint thinner or stripper. While this method is quick, it could affect the wall.
A better approach is to prime the surface to seal over the exterior paint. This will prevent any potential adhesion problems and seal in the harmful vapors underneath.
Once you’ve successfully primed the surface, you can repaint the area with a low or zero-VOC interior paint. Always wear a mask when working with any paint, even if it’s low or zero VOC.
How to Safely Use Exterior Paint Inside
While we generally don’t recommend using exterior paint inside, there are still times you may want to use it. Here are some tips on how to use it safely to avoid any health problems.
- Properly ventilate the room or garage you are using. Open the windows and doors so the paint can dissipate quickly. Also, run fans to increase air circulation.
- Opt for water-based paint when painting indoors. They are less toxic and emit less VOCs. Avoid oil-based paints altogether.
- Wear a breathing mask or respirator to protect your lungs. This also applies when working outdoors. Wearing a mask will protect your lungs from harmful fumes.
- Choose exterior paints with fewer VOCs. Ideally, it should be meant for indoor and outdoor use. In some cases, the paint will cost a little more, but it’s ok.
- Another way to reduce the fumes is to cover the lid or cap when you are not using the product.
- Finally, if possible, run a VOC fume extractor in the space where you are working to pull out harmful compound in the air.
FAQs – Using Exterior Paint Indoors
Is the external and interior paint the same?
No, they are not. As their names imply, exterior paint is meant for outdoor use, while interior paint is meant for indoor use. The reason why it’s not recommended to interchange them is because you don’t have the same conditions inside and outside. Exterior paints usually contain higher amounts of VOCs and usually provide more durability.
Is exterior paint cheaper than interior?
No, exterior paints are typically more expensive than interior paint. And that is because they usually contain additional chemicals to boost their toughness, moisture resistance, and U.V. protection. This is why it’s not a good idea to use interior paint outdoors.
How many coats of paint should you use interior?
Whether you’re painting an interior or exterior surface, you should use at least two coats of paint for good coverage. You may need more depending on the quality of the paint, the color, and the kind of look you wish to achieve. For instance, cheap paints are often thin, so you’ll need to apply several coats to get a good result.
Can you use exterior paint inside a garage?
Garages usually have plenty of ventilation, so it might seem OK to use outdoor paint inside, but this is not recommended. The impact of the fumes will still be felt, which is something you don’t want. If you want to paint your garage, use latex or indoor paint.
Can you use rust Oleum exterior paint inside?
It depends. If the Rust-Oleum paint is meant for indoor use, then you can use it indoors. However, Rust-Oleum spray paint is predominantly oil-based, so they’re best used outdoors. Once again, always check the label to know where you can apply the product.
Is Exterior paint toxic after drying?
Yes, most exterior paints are usually toxic after drying and will continue to give off fumes until after a while. For this reason, any item you paint with exterior paint should be left outside. You should only use it indoors (if you must) after a few months.
Content Summary – Can You Use Exterior Paint Inside
To conclude, it’s simply not a good idea to use exterior paint inside as you would be exposing yourself to harmful chemicals. Exterior paints contain a significant amount of VOCs, which makes them unsafe to use in an indoor setting.
But that doesn’t mean you should get rid of leftover cans of exterior paint. If you have space in your garage, you can store it and use it for touch-ups and other outdoor projects.
For your indoor projects, it’s best to use an interior paint that is specifically designed for the intended surface.