Is It Okay to Use Interior Paint for Outdoor Surfaces?

Home improvement projects often involve painting, but is it a good idea to use interior paint for exterior surfaces? While it may be tempting, it’s not recommended. Two cans of paint may seem identical, but interior and exterior paint are formulated differently. While both contain the same pigment and sheen, exterior paint has additives that protect it from the elements. Water-based latex paint is commonly used for exterior surfaces because it’s durable and can handle temperature changes and humidity. Oil-based paint is better at resisting dirt, but water-based is more commonly used. Interior paint is designed to hold up against scuffs, scratches, and cleaning, making it a poor choice for exterior surfaces. Additionally, the pigment, binders, and liquids used in interior and exterior paints differ. Organic pigments used in interior paint can fade significantly if used outside, making exterior paint the better option.

Paints for interior and exterior use have different formulations. Binders are added to paints to hold the pigment together and provide adhesion to the surface being painted. Exterior paints require binders that provide resistance to environmental factors such as cracking, chalking and moisture. On the other hand, interior paints need binders that offer better abrasion resistance. The types of liquids used in the paints also differ. Interior paints contain low levels of VOCs (volatile organic compounds), which are solvents in the liquid component of paint that can cause short-term and long-term health problems. Look for interior paints with low-to-no VOC levels. Exterior paints may contain higher levels of VOCs than interior paints, so they should not be used indoors. Hybrid interior/exterior-formulated paints are also available as an option.

FAQ about Interior and Exterior Painting

Is it okay to use interior paint on the exterior of a house?
No, it is not recommended to use interior paint on the exterior of a house because exterior paints contain special additives that make them more durable and resistant to harsh weather conditions. Interior paints are not designed to withstand these elements and will eventually crack and peel off.

Do I need special paint for concrete surfaces?
Yes, it is best to use a paint that contains a binder for concrete surfaces because they can expand and contract with temperature fluctuations. Low-cluster acrylics, such as patio and concrete porch paints, are also recommended because they resist UV damage, scuffing, fading, cracking, and conceal imperfections.

What type of paint is best for exteriors?
Oil-based paint is recommended for exteriors because it contains alkyd, which is ideal for resisting dirt and handling temperature changes and humidity. They are also formulated with additives that give them longevity, making them well-suited for exterior painting.

What is VOC in paint?
VOC stands for Volatile Organic Compounds, which are solvents in a chemical form used in many water-based coatings and paints to allow the paint to flow. The EPA has guidelines for low usage of VOCs in interior paint because they can cause health-related issues.

Can exterior paint be used in a bathroom?
Although exterior paint may be more resistant to mold due to moisture, it is not recommended to use it in a bathroom because it contains more VOC, which is not safe for indoor use.

For More Information

Author’s Note: Can Interior Paint be Used for Exterior Surfaces?

If you are not paying close attention to the solvents and binders, the components of latex interior and exterior paints may differ. However, it is best to use paint as it is intended to be used. If you have an outdoor paint project in mind, choose a paint that is labeled for outdoor use to avoid early and excessive fading and cracking.

Other Articles to Check Out

• Step-by-Step Guide on House Painting
• Solutions to Common Painting Problems
• Test Your Knowledge with the Ultimate Painting Quiz

Additional Helpful Resources

• Indoor Air Quality Tips from the American Lung Association
• Learn How to Paint with Tips from Benjamin Moore
• 13 Painting Secrets the Pros Won’t Share on Popular Mechanics

Sources to Consult

• Consumer Reports. “Paint Buying Guide.” May 2014. (June 23, 2014) http://www.consumerreports.org/cro/paints/buying-guide.htm
• Curtis Lumber. “Choosing the Right Paint.” (June 23, 2014) http://www.curtislumber.com/choosing-paint.asp
• Green America. “Eco-friendly Paints and Stains.” July/August 2003. (June 23, 2014) http://www.greenamerica.org/livinggreen/paints.cfm
• HGTV Remodels. “Interior-painting Basics.” (June 23, 2014) http://www.hgtvremodels.com/interiors/interior-painting-basics/index.html
• Lipford, Danny. “Outdoor Painting Tips.” The Weather Channel. Aug. 20, 2010. (June 23, 2014) http://www.weather.com/outdoors/home-improvement/outdoor/outdoor-painting_2010-08-20
• Piper, James. “Evaluating Paint Quality.” FacilitiesNet. August 2006. (June 23, 2014) http://www.facilitiesnet.com/maintenanceoperations/article/Evaluating-Paint-Quality–4992#
• The Paint Kings. “Exterior Stucco Paint vs Interior Paint.” October 28, 2013. (June 23, 2014) http://paintkings.com/exterior-paint-vs-interior-paint/
• The Paint Quality Institute. “Form No. CM10N054: How Color Is Affected by the Ingredients of Paint.” 2010. (June 23, 2014) http://www.paintquality.com/media-center/paint-publications/education/module5.pdf
• The Paint Quality Institute. “The Ingredients of Paint and Their Impact on Paint Properties.” 2010. (June 23, 2014) http://www.paintquality.com/media-center/paint-publications/education/module4.pdf
• The Painted Surface. “How To Choose Interior or Exterior Paint.” (June 23, 2014) http://www.thepaintedsurface.com/how-to-choose-paint.php
• U.S. Environmental Protection Agency (EPA). “An Introduction to Indoor Air Quality (IAQ): Volatile Organic Compounds (VOCs).” July 9, 2012. (June 23, 2014) http://www.epa.gov/iaq/voc.html
• U.S. Environmental Protection Agency (EPA). “Healthy Indoor Painting Practices.” May 2000. (June 23, 2014) http://www.cpsc.gov/PageFiles/121965/456.pdf
• Valspar Paint. “Paint Like a Pro: Frequently Asked Questions.” (June 23, 2014) http://www.valsparpaint.com/en/how-to/faqs/

FAQ

1. Can I use interior paint for exterior surfaces?

No, interior paint is not suitable for exterior surfaces. It is formulated with different ingredients that are not designed to withstand the harsh outdoor environment.

2. What happens if I use interior paint on exterior surfaces?

If you use interior paint on exterior surfaces, it will quickly deteriorate and peel off due to exposure to moisture, UV rays, and temperature fluctuations. It will not adhere properly to the surface, leading to premature failure.

3. What type of paint should I use for exterior surfaces?

You should use exterior paint that is specifically designed for outdoor use. Exterior paint is formulated with additives that provide better protection against weathering and UV rays.

4. Can I use exterior paint for interior surfaces?

Yes, you can use exterior paint for interior surfaces. However, keep in mind that exterior paint may contain higher levels of volatile organic compounds (VOCs) that can be harmful to indoor air quality.

5. What are the benefits of using exterior paint on exterior surfaces?

Exterior paint provides better protection against weathering, UV rays, and moisture. It is also more durable and resistant to fading and cracking, making it ideal for high-traffic areas.

6. How do I know if a paint is suitable for exterior use?

You can check the label of the paint can to see if it is suitable for exterior use. Look for terms like “exterior,” “outdoor,” or “weather-resistant.”

7. Can I use a primer for exterior surfaces?

Yes, you should use a primer for exterior surfaces to ensure proper adhesion and durability of the paint. Choose a primer that is specifically designed for use on exterior surfaces.

8. How long does exterior paint last?

The lifespan of exterior paint depends on various factors, such as the quality of the paint, the surface preparation, and the exposure to weathering. Generally, exterior paint can last up to 10 years or more with proper maintenance.

9. How do I prepare the surface for exterior painting?

You should clean the surface thoroughly by removing dirt, debris, and any loose or flaking paint. Repair any cracks or holes and sand the surface to create a smooth and even texture. Apply a primer before painting.

10. Can I paint over existing exterior paint?

Yes, you can paint over existing exterior paint as long as it is in good condition and properly prepared. However, if the existing paint is peeling or cracking, it needs to be removed before applying a new coat of paint.

11. What tools do I need for exterior painting?

You will need a paintbrush, roller, paint tray, ladder, and drop cloths to protect the surrounding areas. You may also need a pressure washer, scraper, and sandpaper for surface preparation.

12. Can I paint exterior surfaces in cold temperatures?

No, you should avoid painting exterior surfaces in cold temperatures as it can affect the drying and curing process of the paint. The ideal temperature range for exterior painting is between 50°F and 85°F.