Does rubber degrade in sunlight?

Worried about rubber seals or gaskets failing outside? Sunlight can be a hidden enemy that weakens rubber over time, leading to cracks, brittleness, and loss of function.

Yes, most rubber types degrade in sunlight due to UV radiation. Natural rubber and some synthetic rubbers will crack, fade, or harden when exposed to sunlight for long periods. Special rubbers like EPDM and silicone resist sunlight much better.

I have seen outdoor rubber parts turn brittle, lose flexibility, and start leaking or breaking much sooner than expected—especially when the wrong material was used.

Why Does Rubber Degrade in Sunlight?

The sun emits ultraviolet (UV) rays that attack the chemical structure of rubber. Over time, these UV rays break the bonds in the rubber molecules, causing it to lose elasticity, change color, and develop surface cracks.

UV radiation is the main cause of outdoor rubber failure. Most rubbers will dry out, fade, and crack unless they are specially formulated for UV resistance.

🛠️ How Sunlight Affects Different Rubbers

Which Rubber Types Resist Sunlight Best?

Some rubbers are specially designed to stand up to sunlight, ozone, and weather for years. I always suggest these for outdoor jobs.

EPDM and silicone rubbers have outstanding resistance to sunlight and UV rays. Neoprene and FKM (Viton®) are also fairly resistant, but less so than EPDM and silicone.

EPDM is the top choice for outdoor gaskets, weatherstripping, roofing, and irrigation hoses. Silicone also stays flexible and does not crack or fade, even in direct sun.

🛠️ Rubber Selection Table for Outdoor Use

I always remind people: using indoor-grade rubber outside will lead to faster failures.

Can You Protect Rubber from Sunlight Damage?

Sometimes you have no choice but to use a rubber that isn’t UV-resistant. In that case, I recommend extra steps to slow down the damage.

Covering, painting, or coating rubber can extend its life outdoors. But for the best results, use a UV-resistant rubber in the first place.

Practical Tips

• Install rubber parts in shaded areas if possible
• Use paint or UV-blocking coatings⁵ on exposed rubber
• Clean and inspect outdoor rubber regularly
• Replace any cracked or hardened rubber right away

What Happens When Rubber Degrades in Sunlight?

Rubber that sits in direct sun for months or years will:

• Lose its soft, flexible feel
• Become sticky or powdery
• Crack and split, especially where stretched
• Turn pale, grey, or faded in color
• Lose sealing or cushioning ability

I have seen outdoor gaskets and hoses fail from sun exposure, causing leaks and extra maintenance costs.

🛠️ Rubber Failure Table

How to Choose the Right Rubber for Outdoor Use?

Picking the right material saves time and money. I always review the expected sun, weather, and temperature conditions before choosing.

For long-lasting outdoor use, pick EPDM or silicone rubber. Avoid natural rubber and low-cost synthetic rubbers for direct sun exposure.

When in doubt, always ask your supplier for the UV resistance rating of the rubber before you buy.

Conclusion

Yes, most rubber degrades in sunlight, especially natural rubber and many basic synthetic types. EPDM and silicone are the best for outdoor and sunlight exposure. Choose wisely for the longest service life.