Why Does Spray Foam Turn Yellow Over Time?

If you've ever seen spray foam that was installed a while ago, you might have noticed a more yellow hue. Perhaps you did some air-sealing with can foam and are surprised to see that the foam, once bright white, has become yellow. Why exactly does spray foam turn yellow over time?

South Central Services has insulated hundreds of homes in and around Carlisle, Pennsylvania, with spray foam insulation. While yellowed spray foam is not particularly desirable, the change in color does not indicate that the foam is ruined. However, it can indicate that an action step needs to be taken.

By the end of this article, you will understand:

• Why spray foam changes color
• What causes spray foam to yellow over time
• How to prevent spray foam from yellowing over time
• What to do if your spray foam insulation has started to yellow

Spray Foam Goes Through Many Color Changes.

If your spray foam insulation has started to turn yellow, it is not the first color change your foam has been through. Since spray foam is created through a chemical reaction, it experiences several color shifts during manufacturing.

At the start, spray foam components in the chemical drums look similar to motor oil. When these liquid chemicals initially turn solid, they look closer to brown. Once the foam starts to rise and cure, the foam looks more white or cream-colored.

In a way, the yellowing of spray foam over time is a natural change.

Yellowed Spray Foam Is Normal And Caused By UV Rays.

Ultraviolet rays can damage anything. We wear sunscreen to protect our skin. We can see the change in color for fabric and wood when exposed to ultraviolet light. The same principle applies to spray foam.

When spray foam is exposed to ultraviolet rays, the otherwise white foam can turn yellow over time. If your foam doesn't receive direct sunlight, it should theoretically look the same as when it was first sprayed.

Ultraviolet Rays Can Compromise Spray Foam Performance.

Spray foam insulation should not be exposed to UV rays. Enough exposure to ultraviolet light will break down spray foam over time.

This is why spray foam installed on a home's exterior, such as a spray foam roof, must be covered with a protective coating. However, even spray foam in an attic could receive UV rays from a window.

If your spray foam is yellowing, it should be protected by a coating or a covering such as drywall.

The Bottom Line About Why Spray Foam Turns Yellow Over Time

Spray foam insulation will turn yellow over time if exposed to ultraviolet light. To protect the performance of your insulation, be sure to cover up or coat your foam. Your contractor should have already installed protective coatings over your spray foam if there was a chance for UV rays to deteriorate the product.

If you're concerned about the yellowing of your foam, a covering or drywall can be a simple solution to stop the UV light.

Now that you understand why spray foam turns yellow over time, your next step is to:

• Learn how long spray foam insulation is meant to last
• Discover how spray foam insulation can save money over time
• Estimate the cost of a spray foam upgrade in your home