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Is Using Exterior Paint Inside Harmful?

Is Using Exterior Paint Inside Harmful?

It may seem like a good idea to reuse paint you have in storage when repainting or touching up. After all, you don't want to waste paint. But what if you need to touch up an interior surface? Can you use exterior paint to do it? In short, it's possible to do so, but it's not the safest choice or the wisest way to protect your surfaces.

Using Exterior Paint Inside: Health Risks

Different paints have different chemical properties because they're formulated for different purposes and designed to adhere to different surfaces in different conditions. For example, interior paint is made to be scrubbed and allows cleaning without the cleaners or moisture damaging the surface.

Stain resistance is a common quality of interior paints. After all, you don't want a spatter to ruin fresh kitchen cabinet painting or bedroom paint to need a touchup after one bump of a piece of furniture against the wall.

Exterior painting demands products that can combat fading and mildew. Their high durability often comes from the volatile organic compounds (or VOCs). VOCs emit strong smells and sometimes smoke. Even with a solid interior ventilation system, exterior paint is still a dangerous health risk for you, your family, and your pets, since you'd be breathing in volatile organic compounds.

And even in small amounts, these compounds can cause and exacerbate both respiratory and gastrointestinal issues. It's simply not worth the risk when it's a choice between keeping you and your family healthy and having to buy more paint for your interior surfaces.

Using Exterior Paints Inside: Performance and Finish Risks

Safety risks are only part of the problem with using exterior paint inside. The other issue is the performance risks. You're not going to have the same finish, aesthetic appeal, or performance from using exterior paint inside or vice versa. Namely, there's likely not the same depth and dimension to the finish that you want when interior painting. Paints with lower-gloss sheen tend to be preferred by exterior painting contractors. Those sheens are generally more resilient against outdoor grime and contaminants and are designed for harsher conditions.

And if you're tempted to mix interior and exterior paints, we wouldn't advise it. It won't take away the volatile organic compounds that make exterior paints a risk, and it will only diminish the performance of the resulting finish on your interior surfaces. That makes it more likely you'll see imperfections sooner and have to remove and repaint before your schedule or budget are ready for it. Interior paint and exterior paint are formulated differently for a reason, and mixing them means that neither of them are doing their intended job.

Tips for Avoiding These Paint Issues

The temptation to misuse exterior paint inside can happen for many reasons. Here's how to avoid this situation:

  • Too Little Interior Paint: If you ran out of interior paint before your projects were done, it's a good idea to accurately measure the square footage of the area for future reference. If you need guidance, here's a solid tip from PPG: "One gallon can of paint will cover up to 400 square feet, which is enough to cover a small room, like a bathroom. Two gallon cans of paint cover up to 800 square feet, which is enough to cover an average size room."

  • Interior Paint Deterioration: Perhaps you got enough interior paint, but it's been a long time since you opened and used it. If paint is improperly stored, it deteriorates and must be disposed of. In the future, storing interior paint in a cool, dry place should keep it intact. Just make sure the containers are airtight and clearly labeled.

  • Interior Paint Damage: If interior paint was peeling, blistering, or bubbling, there are either issues with the paint application, the underlying surface, or both. Interior painting contractors can help remove old paint, check the surface for structural integrity, and reapply high-quality interior paints and finishes that will stand the test of time without putting you and your household at risk.

The local house painters at Trico Painting don't want you to struggle through your painting project or misuse paints in a way that only causes more stress and costs more money.


We can help correct paint damage and apply new paint, and there's no need to figure out paint storage. No paint will go to waste, and your walls, ceilings, or cabinets will look better and last longer. Ready to get things fixed? Contact Trico Painting to talk about interior painting services today.