The reasons why exterior paint isn't the recommended way to go.
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Garage walls—they're kind of outside, kind of inside. Some are temperature controlled, others aren't. They can double as laundry rooms, storage rooms, man caves, and more. It's a lot to take in and can pose quite the conundrum when trying to determine which variety of paint is best for brushing on the walls, but we did the legwork, and it all comes down to ventilation.

While a couple of other factors do weigh in, it's the fumes in an enclosed space that rule out exterior paint. Interior latex paint, specifically varieties formulated for high-traffic areas, is what's best for garage walls thanks to its fast-drying speed, minimal odor, and easy clean up as compared to oil-based versions. Exterior paint typically has more toxins and a stronger smell due to anti-mildew properties, making it best left for exterior spaces—and completely open air ones at that.

The sheen needed for garage walls is also important to note. Semi-gloss or satin finishes are the best choices as they'll provide a cleanable surface and just enough reflection to camouflage inevitable imperfections like dents, screwheads, and uneven texture. To that end, primer can be an important step in the process, especially if you're painting over unfinished drywall that would otherwise just soak up paint leaving it rough and bumpy. If your walls are already painted and devoid of staining, you can likely get by skipping the priming step.

One more thing to pay attention to if you're painting over another layer of old paint is determining whether it's oil-based or latex. You'll need to sand down oil-based paint prior to applying latex. The purpose is to remove the sheen so the latex paint can properly adhere. After you've properly sanded, wipe down the walls to remove any grit, dirt, or dust.

Regardless of whether you're painting over dry wall or painting over already-painted walls, the surface will need to be completely clean. A shop-vac, damp sponge with soapy water, or even a good sweeping could do the job, depending on what you're working with.

As for color selection, that's one decision that's entirely up to personal discretion. But if you really want to know our thoughts, we're of the mindset that you can never go wrong with white walls.