Yes, epoxy can generally be applied over an existing coating, but several important considerations should be taken into account:
Previous Coating Integrity First and foremost, assess the condition of the existing coating. If it is damaged, delaminating, or otherwise compromised, applying epoxy over it may not provide a durable or long-lasting solution. In such cases, it is often better to remove the old coating and start with a clean substrate.
Adhesion Proper adhesion between the existing coating or substrate and the new epoxy layer is crucial for a successful application. The surface must be clean, dry, and free from any contaminants like dust, oil, grease, road tar, paint, or other residues that could hinder the epoxy's ability to bond effectively.
Compatibility Ensure that the existing coating is compatible with the epoxy you plan to apply. Different epoxy formulations may have varying interactions with certain coatings potentially leading to adhesion issues or other undesirable effects such as rejection aka “fish eyes”.
Surface Preparation Thoroughly prepare the existing surface before applying the epoxy. Depending on the condition of the coating or substrate, this may involve cleaning or degreasing, and should always include sanding. If you can’t achieve an acceptable surface to recoat then you should consider removing the old coating entirely to create a suitable bonding surface for the new epoxy.
Testing Before applying epoxy over the entire area, if you’re not confident that the prepared surface will accept the new epoxy, then it is recommended you conduct a small test patch to check the adhesion and compatibility between the existing coating and the epoxy. This test patch will help you identify any potential issues before committing to a full application.
NOTE – It is extremely hard to get epoxy to bond to an existing floor with a urethane finish. To do so requires a significant amount of sanding and the smallest of spots that are not sanded enough will result in rejection of the new resinous product.
Type of Epoxy: Different epoxy products have different characteristics and purposes. Some epoxy coatings are specifically designed for direct application over existing coatings or substrates, while others may require specific primers or surface preparation techniques for optimal adhesion.
Manufacturer's Guidelines: Always follow the manufacturer's instructions and recommendations for applying epoxy over an existing coating or substrate. They will provide specific guidelines on surface preparation, compatibility, and any additional steps required for a successful application.
In summary, while epoxy can be applied over an existing coating, it is crucial to ensure proper surface preparation, compatibility, and adhesion to achieve a successful and long-lasting result. Always refer to the manufacturer's guidelines and consult with technical support if you have any doubts or questions about the specific application process.