Question: My epoxy floor has turned yellow, especially near the windows and anywhere direct sunlight hits it. Can it be fixed, or does the whole floor need redoing?
Answer: Yellowing epoxy can almost always be fixed without redoing the floor. The yellowing is in the surface layer, not the body of the coating. Standard epoxy resin is not UV-stable — its chemical structure breaks down under sunlight and turns yellow or amber over time, which is why the effect concentrates where the sun lands. The fix is to lightly abrade the surface and apply a UV-stable topcoat, usually an aliphatic polyurethane, which stays clear under sunlight. Where the client wants a colour change, a pigmented flake or tinted layer can be applied at the same time.
Why Epoxy Turns Yellow in Sunlight
- Non-UV-stable topcoat is the primary cause. Aromatic epoxy resins yellow when exposed to ultraviolet light.
- Direct sunlight through large windows, skylights or open doorways accelerates the change dramatically.
- Cheap or mislabelled resin can yellow faster and more unevenly.
- Chemical exposure from some cleaning products or spills can also discolour the surface, though this looks different from UV yellowing.
- Age — even good epoxy in a sunny spot will eventually shift colour without a UV-stable topcoat.
Polyurethane (PU) topcoats are aliphatic, meaning they are UV-stable and stay clear — which is why high-traffic commercial and showroom floors finish with a PU layer over the epoxy.
Yellowing vs Other Discolouration
| Appearance | Likely cause |
|---|---|
| Even yellow or amber tint in sunlit areas | UV exposure on a non-UV-stable coat |
| Patchy yellowing near a window | Localised sun exposure, possibly uneven coat |
| Yellowing plus soft or sticky patches | Chemical attack or a mixing/curing fault |
| Whitish bloom or haze | Moisture during application or cleaning residue |
| Fading rather than yellowing | Pigment breakdown in a coloured system |
If the surface feels sticky or soft, treat it as a coating fault rather than cosmetic yellowing and have it assessed before any recoat.
What a Recoat Involves
- Assess the existing coat for adhesion and any soft spots.
- Lightly abrade the surface so the new topcoat can key in.
- Clean thoroughly to remove dust and any contaminants.
- Apply a UV-stable PU topcoat (or a pigmented layer if a colour change is wanted).
- Allow curing before foot traffic returns, usually overnight for a same-day recoat.
A recoat is far cheaper and less disruptive than grinding out and relaying the floor, and it directly addresses the cause rather than just masking it.
Costs in KL and Selangor
Published guidance for this problem is RM 280 to RM 1,800+, depending on area, with a topcoat refresh typically quoted around RM 12 to RM 28 per square foot. KL Servis Rumah publishes epoxy floor repair and recoating from RM 14 per square foot, self-levelling epoxy floor from RM 22 per square foot, and flake / quartz broadcast epoxy from RM 26 per square foot. Epoxy work carries the published 5-Year Delamination & Yellowing Warranty.
See epoxy vs polyurethane flooring guide for the fuller comparison.
Frequently Asked Questions
Can yellowed epoxy be fixed?
Yes. The surface is lightly sanded and a UV-stable topcoat is applied, restoring the clear or coloured finish without relaying the floor.
How do you prevent epoxy yellowing?
Use a UV-stable aliphatic PU topcoat on any area exposed to sunlight. This is the standard finish for floors near windows, skylights and open doorways.
Does yellowing mean the floor is failing?
Not structurally. UV yellowing is a cosmetic change in the surface layer. Soft, sticky or peeling patches are a different matter and should be assessed separately.
Can you change the colour while recoating?
Yes. A pigmented flake or tinted layer can be applied during the recoat if you want to change the look at the same time.
How long does an epoxy floor last?
Interior areas away from sunlight commonly last 8 to 15 years. High-UV areas may need a topcoat refresh every 3 to 7 years.
Get the Floor Recoated Properly
The useful first step is confirming whether the yellowing is simple UV exposure or an underlying coating fault — the two need different handling. KL Servis Rumah provides epoxy flooring services across Kuala Lumpur, Petaling Jaya, Subang Jaya, Shah Alam, Puchong, Cheras and Klang.
Send a photo of the yellowed area and tell us how much of the floor is in direct sun — WhatsApp our epoxy team.