Epoxy fails when the slab is not properly profiled. The correct prep is: remove all coatings and adhesives, diamond-grind the floor to a clean 30-60 grit profile, vacuum completely, then apply epoxy within 24 hours. You are aiming for a concrete surface texture like medium-grit sandpaper.
Epoxy bonds mechanically to the concrete, not chemically. A smooth, troweled slab has nothing for the epoxy to grip, and it peels in sheets within months. Industry standard (ICRI CSP 3-5) calls for a light-to-medium acid etch or diamond grind profile.
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Acid etch is cheaper but inconsistent. It leaves water in the slab, creates uneven profile, and does not remove glues or coatings. For a 5+ year epoxy system, diamond grind is the only reliable method.
A: No. The paint must be removed by grinding or shot blasting first. Epoxy over paint always fails.
30 to 60 grit metal bond. You should see a clear, uniform scratch pattern but no aggregate exposure unless the slab is very smooth.
A: Yes. Trowel-finished new concrete is too smooth. Light grind with 30/46 to open the surface.
Epoxy success starts in the prep. A clean 30-60 grit diamond profile, proper dust removal, and coating within 24 hours is the recipe. contact JOY TECH for metal-bond discs sized to your grinder.
