Adding a fresh coat of paint is an easy way to update your garage without a complete renovation. But, many homeowners wonder “should you use interior or exterior paint for garages?”
There are some do’s and don’ts when painting these walls, including what type of paint to use and when to use it.
In the rest of this article, I’ll explain what type of paint you should use inside your home. Then, I’ll cover how temperature may make an impact and why some garages are better left unpainted.
Should You Use Interior or Exterior Paint for Garages?
It may seem simple, but you could argue it either way.
Your garage is inside your house, so it would make sense to use interior paint. On the flip side, cinder block garage walls are exposed to harsher conditions than the insulated walls inside your home.
Does that mean you should use exterior paint for garage walls?
Always use interior paint inside your home or garage. Exterior paint is formulated to protect your home from extreme weather. It contains chemical additives that can be toxic to your family if used inside. Only use exterior paint in open spaces with good airflow.
All interior and exterior paints comprise the same four components: resin, solvents, pigments, and additives.
However, the composition of those components differs significantly between interior and exterior paints.
The first difference is the type of resin used to bind the pigment to the paint.
The resin is what allows the paint to stick to your walls. The most common paint resins are acrylic, alkyd, and epoxy resins.
We’ve talked about epoxy resins extensively on this site. They’re commonly used in flooring and sealants because of their high durability.
However, acrylic and oil-based (alkyd) paints are very common in homes.
Acrylic Resin (Acrylic or Latex Paints)
Acrylic resin is a water-based paint that gives off relatively low amounts of volatile organic compounds (VOCs) while drying. That makes it extremely popular in both interior and exterior paints.
Acrylic is easy to clean and dries quickly compared to oil-based paints. In fact, most acrylic paints dry as quickly as 20 minutes after painting.
Mixing acrylic paint with an epoxy base creates what’s commonly called latex paint. Interior latex paint is very durable and great for your garage.
Epoxy paints fall under this category as well.
However, epoxy is most likely used as a floor coating or sealant because it adheres well to porous surfaces like concrete. It is also corrosion-resistant, breathable, and easy to clean.
Alkyd Resin (Oil Based Paints)
Alkyd resin paints are oil-based and can be used inside or outside the home.
Oil-based paint is more durable than acrylic paint, so they’re typically used on areas that receive more wear and tear, like doors, window sills, or trim.
However, alkyd paints can be hazardous because they give off more VOCs than water-based paints. They also require paint thinners or turpentine to clean up or remove, which means more chemicals.
Additives Can Make Exterior Paint Toxic
Air quality is critical inside your home. With that in mind, the additives are another significant difference between interior and exterior paint.
Interior paints are made with fewer chemicals and additives, so they don’t adversely impact your health.
By contrast, exterior paints are designed to withstand the elements, repel mildew, and be chip-resistant. They must be rated to survive scorching summers, freezing winters, downpours, and a constant barrage of UV rays from the sun.
That is done through the use of chemical additives.
These include mildew-resistant chemicals, fungicides, anti-fading compounds, and anti-chipping solutions. As the paint dries, those additives expel gasses in a process called outgassing.
Most paint manufacturers recommend painting in a well-ventilated area and keeping the area ventilated for up to 48 hours after you finish.
However, that’s not always enough when using exterior paint.
Most outgassing happens within 48 hours of painting but continues in smaller amounts for several years. These gasses can harm humans and pets in enclosed spaces.
That’s why the United States Environmental Protection Agency (EPA) recommends never using exterior paint inside your home. This includes your garage walls.
Can You Use Interior Paint in an Unheated Garage?
As with any paint, one of the biggest concerns is the room temperature when painting.
Unlike our living room, most garages aren’t climate-controlled, limiting when to start a painting project.
You’re looking for that ‘Goldilocks point’ that’s neither too hot nor too cold during the painting and drying process.
It can adversely affect your walls if it gets too extreme in either direction.
When temperatures are too cold, water-based paint will have difficulty adhering to the surface, making it much harder to dry correctly.
If temperatures are too hot when painting with latex paint, they won’t dry properly and can become gunky and too wet on your wall. This can quickly lead to cracks and bubbles in your paint.
It is recommended that the temperature be at least 50 degrees Fahrenheit (10 degrees Celsius) and not higher than 90 degrees Fahrenheit (32.2 degrees Celsius) over the entire painting time and drying process.
High humidity has similar effects to high temperatures, causing the paint not to dry correctly and damaging the finish.
Manufacturers recommend controlling the temperature and humidity levels while painting your garage walls.
In colder climates, that means using an electric or propane garage heater in your garage. You’ll want to invest in a portable air conditioner or garage dehumidifier in warmer areas.
Should You Paint Your Garage?
So why don’t more people paint their garages?
In most cases, this comes down to simple cost savings for the home builder.
Paint best adheres to a clean, flat surface. Because most garages don’t have finished walls (drywall or other wall covering), it takes more paint to get a good finish.
Before you start painting, you’ll need to thoroughly clean off any dirt in existing homes. Also, if there are any imperfections on the walls, those will need to be fixed.
That adds additional costs that most homeowners just aren’t willing to pay.
Ultimately, it comes down to personal preference and how much effort you’re willing to put in to have a great-looking paint job.
Wrapping It Up
Never use exterior paint for garage walls or any other interior room. You can use the same paint for garage walls that you would use throughout the rest of your home.
The best type of paint to use in your garage is acrylic latex paint because it is durable, quick-drying, and easy to clean. This article has some great recommendations for the best garage wall paints.
You can use latex paint, even if you have a heated garage. You’ll want to avoid extreme temperatures during painting and drying, however. You may need to temporarily heat or cool your garage so it stays between 50 and 90 degrees Fahrenheit (10 to 32 degrees Celsius).
Once you’ve decided to paint your garage interior, the next step is to figure out what color to paint it. While I recommend a simple white or light gray, there are many other paint schemes to choose from. Here is a huge guide on choosing the right color for your garage walls.
