The Science of UV (Sun) Damage to Coatings

Mom has always said, “Don’t go outside without your sunscreen.”
We say, “Protect your home with its sunscreen – paint.”

Think of paint as the sunscreen protectant for your home; in this article we explain how paint protects against harmful UV rays. 

Table of Contents

1. Understanding UV Radiation
2. The Effect of UV Rays on Paint and Coatings
3. UV Damage to Wood Stains and Finishes
4. Impact on Vinyl and Polymer Coatings
5. Mitigating UV Damage
6. Conclusion

Understanding UV Radiation

Sunlight is composed of visible light, infrared radiation, and UV radiation. UV radiation can be further divided into three categories: UVA, UVB, and UVC, with UVA and UVB being the most relevant to coating damage. UV radiation, especially UVA, penetrates the atmosphere and has a significant impact on materials exposed to sunlight.

The Effect of UV Rays on Paint and Coatings

UV rays can cause photodegradation, a process where the chemical bonds in a substance are broken down by light. In paints and coatings, this leads to fading, chalking, and loss of gloss. Pigments in paint absorb UV light and can break down over time, leading to color fading. Certain pigments are more susceptible to UV damage than others. UV rays can cause the binding agents in paint to degrade, leading to a powdery residue on the surface, known as chalking.

UV Damage to Wood Stains and Finishes

UV exposure can cause wood stains and clear finishes to dry out, leading to cracking and peeling. This compromises the protective layer and exposes the wood to further damage. Wood itself can discolor under UV exposure, often turning gray or yellowish, depending on the type of wood and finish used.

Impact on Vinyl and Polymer Coatings

Prolonged UV exposure can make vinyl sidings and polymer-based coatings brittle. It can also lead to warping and distortion due to the breakdown of plasticizers and other components.

Mitigating UV Damage

Many modern exterior paints and finishes are formulated with UV inhibitors or stabilizers to reduce the rate of UV degradation. Regular maintenance, including reapplying coatings and finishes, can help mitigate UV damage. In areas of high UV exposure, additional protective measures like shades, awnings, or UV-blocking window films can be effective.

Conclusion

UV radiation from the sun is a major culprit in the degradation of home coatings. It can cause fading, chalking, cracking, and other forms of damage to paints, stains, and synthetic materials. Here in San Luis Obispo, the frequent temperature changes paired with the excessive sun exposure are a recipe for coating failure. Contact Rogall + Co. today to learn how you can protect your home from the sun's rays.