Can You Use Exterior Paint Inside?

If you have some exterior paint left over from painting the outside of your house, you might be wondering if you can use that same paint inside the house. Industry-wide, using exterior paint inside is not recommended. In fact, it can be downright dangerous.

We know that it can be tempting to use leftover paint for more creative purposes, and you probably like the exterior color you chose. However, exterior paint formulas are not the same as interior paint formulas, and there are several very important reasons why.

Exterior Paint VS. Interior Paint

Exterior Paint

These paints do two very different things. Exterior paint has features that make it extremely durable against a wide range of weather conditions. It must withstand UV from the sun, moisture and water resistance from the rain, extreme heat and cold, and even impact resistance against hazards like hail and scuffs during wind storms.

Outdoor paint is also durable and flexible. It uses some heavy-duty chemical compounds to achieve these qualities, including VOCs that outgas safely when used outdoors.

Interior Paint

Indoor paint, on the other hand, is designed to be human-safe. Paint manufacturers need indoor paint to be safe enough for children and pets to literally lick the walls. Indoor paints must not outgas significantly, contain significant VOCs, or shed toxic flakes. They tend to have organic pigments and include mildew-resistant formulas to keep families safe from mold and dampness indoors.

Can You Use Exterior Paint Inside?

Health and Safety Risks

The simple answer? No. Using exterior paint inside of your home primarily poses a health and safety risk. Exterior paint can contain dangerous VOCs and the outgassing can make your entire home interior toxic for days - something that you don't have to worry about when using the paint outdoors.

Toxins in exterior paint may include Toluene, Xylene, Benzene, and Trichloroethylene. These can impact the nervous system, cause headaches and tremors, and pose a carcinogen (cancer) risk. You do not want to use exterior paints in an enclosed area.

The Rare Exceptions

However, there are a few situations where you might use exterior paint indoors. This involves indoor-outdoor spaces where you need paint that can endure the elements but the space may often be closed off. Covered porches, sunrooms, outdoor living with adjustable enclosures, and the inside of your garage may all meet these requirements.

To make exterior paint use safe for indoor-outdoor spaces, be sure to open up the space while you paint and for several days as the paint is drying. This will give your exterior paint a chance to safely outgas. It is also advised that these areas not be used for the unsupervised play of young children or pets who are prone to chew walls or furniture.

Types of Interior Paint

For your truly interior spaces, it's important to choose the right finish for your space. For example, semi-gloss and high-gloss are more moisture-resistant and easy to scrub. This makes them a better choice for bathrooms and kitchens. Satin paint is the most versatile and preferred throughout the home, while Eggshell offers a softer appearance that still maintains some durability. 

Cougar Uses The Right Paint For The Job

While it may be tempting to start using the last of your exterior paint inside, look for opportunities to create outdoor accents instead. Paint your porch railings or touch up your shutters with exterior paint. For indoor spaces, always choose low-VOC, safely formulated interior paint.

The best way to ensure you always have high-quality paint is to hire a skilled painting professional who understands the painting requirements for each space of your home. Cougar Painting can help you determine the perfect paint color and formula for your indoor, outdoor, and transition spaces. Contact us today to explore exterior and interior painting options for your home.