These are the twelve mistakes we see over and over — on DIY installs, and on cheap professional ones. Any one of them will shorten the life of the floor by years.
1. Skipping the moisture test
Concrete moves vapor. If you coat a slab that's above the threshold RH, hydrostatic pressure will push the coating off in sheets within months.
2. Etching instead of grinding
Acid etch doesn't remove oil, doesn't remove previous coatings, and doesn't create enough profile for a 20-mil coating to bond. Diamond grinding or shot-blasting is not optional.
3. No primer
Priming stabilizes the slab, blocks vapor, and gives the base coat something to bite into. Skipping it saves an hour and shortens the floor's life by years.
4. Water-based epoxy in a working garage
Water-based epoxies are thin, low-solids coatings — closer to paint than to a true 100% solids system. They peel under hot tires.
5. No UV-stable topcoat
Epoxy ambers in sunlight. If any part of the floor sees UV, you need a polyaspartic or polyurea topcoat.
6. Not filling cracks and joints
Untreated cracks telegraph through the coating within a season. Fill with a semi-rigid polyurea before coating.
7. Broadcasting flake too thin
Full reject means covering the base coat completely with flake so no wet resin shows through. Half-broadcast finishes look thin and fail earlier.
8. Coating over old paint
Any coating you put down is only as strong as what's under it. Remove old paint mechanically before installing.
9. Rushing recoat windows
Every product has an overcoat window. Coating too early traps solvents; coating too late requires a scuff-sand.
10. No slip additive on wet-service areas
A high-gloss topcoat is slippery when wet. Ramps, entryways, and wash bays need aggregate in the topcoat.
11. Buying by price alone
The cheapest quote almost always skips prep. Match on scope and system, not on a lump-sum number.
12. No written warranty
If it's not in writing, it doesn't exist. Every proposal should include a material and labor warranty with a stated duration.