Ninety percent of failed epoxy floors fail because of concrete prep, not the coating. Here's every step a competent contractor should walk through before opening a can of resin.
1. Inspect the slab
Look for cracks, spalls, delamination, previous coatings, oil stains, and efflorescence. Every one of those is a separate line item in the proposal.
2. Moisture test
Calcium chloride or in-situ RH testing. A slab that reads over 3 lbs/1000 sf/24 hr (or above 75% RH) needs a moisture-mitigating primer or the coating will delaminate as vapor pressure builds underneath.
3. Mechanical profile
Diamond grind (residential and light commercial) or shot-blast (heavy commercial and industrial). Target a CSP 2–3 profile for most coating systems. Chemical etching is not adequate for a full-thickness epoxy install — it doesn't remove contamination and doesn't create enough tooth.
4. Crack chase and fill
V-groove cracks with an angle grinder, vacuum, then fill with a semi-rigid polyurea. Static cracks can be filled flush; joints that move should be treated as joints and honored in the finished floor.
5. Spot patch and level
Feather in low spots and honeycomb with a fast-cure epoxy mortar. Skimming the whole floor is usually unnecessary and expensive; targeted patching is what a good crew does.
6. Vacuum and prime
HEPA-vac the entire slab. Any dust left on the surface becomes a bond-break. Prime with a moisture-tolerant epoxy primer sized to the slab's RH read.