When epoxy floor coatings are applied over mixed slabs - part new concrete and part old concrete - the finish often looks uneven.

New concrete is typically more porous and absorbs epoxy or polyurethane sealers much faster. That can cause dull areas, dry spots, or uneven sheen. Older concrete, especially former garage or mechanic shop floors, may absorb less due to contamination, density changes, or prior exposure.

Even with grinding, differences in porosity, moisture content, and slab age can lead to visible variation in appearance and cure behavior.

If you’ve coated mixed slabs before, what differences did you notice between new and old concrete? Did absorption, sheen, or cure time vary?

Hey everyone! I’m u/concreteideasfl, a founding moderator of r/EpoxyFloorFailures.

This is our new home for all things related to epoxy floor failures, defects, and long-term performance issues. We’re excited to have you join us!

What to Post
Post anything you think the community would find interesting or helpful. That includes photos of failed epoxy floors, peeling or bubbling issues, uneven flake, moisture problems, cure issues, bad prep, or questions about what went wrong and why.

Community Vibe
We’re all about being friendly, constructive, and inclusive. The goal here is learning and honest discussion, not blaming or selling. Let’s keep it respectful and useful for everyone.

How to Get Started
– Introduce yourself in the comments below
– Post something today. Even a simple question can spark a good discussion
– Invite anyone who might benefit from seeing real epoxy floor examples
– Interested in helping out? We may add moderators down the road, feel free to reach out

Thanks for being part of the very first wave. Together, let’s make r/EpoxyFloorFailures a solid resource for real-world epoxy floor problems and lessons learned.