How to Avoid Yellowing in Epoxy Topcoats

Amee Curtis
Sep 26, 2025
2 min read

Tired of yellowed, cloudy epoxy floors? Learn what causes ambering and how to prevent it with UV-stable products, proper layering, and the right topcoat strategy.

The floor looked perfect at install. Smooth, glossy, clean. But weeks later, your client calls back asking, “Why is it turning yellow?”

Epoxy yellowing is one of the most common coating complaints—and one of the easiest to prevent… if you plan for it.

This guide breaks down why epoxy topcoats yellow, How to Avoid Yellowing in Epoxy Topcoats, and which products and methods give you crystal-clear results that stay that way.

Why Epoxy Turns Yellow and How to Avoid Yellowing in Epoxy Topcoats

The culprit: UV exposure

Epoxy resins are sensitive to ultraviolet light
Even indirect sunlight through windows can cause ambering
Heat accelerates oxidation, causing yellowing or clouding

Epoxy was never designed to be a long-term clear topcoat. That’s why choosing the right final layermatters.

Other Causes of Discoloration

Oxidation over time (especially with solvent-based epoxy)
Topcoat applied too thick (leads to blushing and haze)
Poor mixing or incorrect ratios (leaves uncured components)
Chemical exposure (bleach, acids, deicers, etc.)
Low-quality resin systems or DIY kits

How to Prevent Yellowing

1. Never use epoxy as the final topcoat

Instead, use a UV-stable topcoat such as:

Polyaspartic
Aliphatic polyurethane
Urethane acrylic hybrid (for decorative use)

These systems are designed to stay clear, resist sun damage, and keep your floor looking fresh.

2. Use Pigment or Flake Broadcasts

Flake systems naturally hide UV yellowing—even if your basecoat darkens slightly, it won’t show. Great for garages, retail, or decorative installs.

3. Use a Tinted Epoxy Instead of Clear

Ambering won’t be noticeable if the resin is already pigmented. This also gives you deeper, richer color tones.

4. Block or Diffuse Sunlight During Cure

Direct UV exposure while the epoxy is curing can speed up yellowing. Close blinds, use shade barriers, or install at night when possible.

Recommended Systems from PNW ECS

System Type	Use Case	Topcoat Product
Flake Broadcast	Garage / Retail	Kretus Polyaspartic 92 Fast
Solid Color Epoxy	Commercial Interior	Citadel Polyurea-1 HD
Polished Look	Showroom	Aliphatic Polyurethane Gloss
Decorative Quartz	Food-safe / Kitchen	Urethane Cement + Polyaspartic

Products to Avoid as Final Topcoat

DIY epoxy kits
Low-viscosity clear epoxy without UV blockers
Solvent-heavy, non-aliphatic urethanes
Any product not labeled “UV-stable” or “non-yellowing”

Conclusion

Epoxy might be the foundation—but UV-stable topcoats are the finish line.

Avoiding yellowing is simple: use the right layers, follow proper mix and cure guidelines, and never rely on epoxy to do a polyurethane’s job.At PNW ECS, we’ll help you build the right system that performs beautifully—and stays that way.

📍 Ask About Topcoats at PNW ECSAvailable in Sandy & Fife. Bring in your job specs or a photo—we’ll help you layer it right and avoid ambering headaches.