Quick Answer
A two-car garage (about 40 m2) takes one day to prep: clean, patch cracks, grind with a 30/46 metal-bond disc on a push grinder, vacuum, and apply epoxy the same evening. The goal is a CSP 3 profile—uniformly scratched, no glossy patches.
Step by Step
- Clean the floor. Degrease oil spots; they prevent adhesion.
- Patch cracks and spalls with epoxy mortar. Let cure 24 hours.
- Edge grind first with a 5-inch cup wheel. Then the big grinder does the middle.
- Grind with 30/46 grit metal bond. Our double-S segment discs works on most push grinders.
- Second pass at 120 grit to remove the heavy scratches.
- Vacuum twice. Wipe with a damp microfiber cloth to catch fine dust.
- Apply epoxy the same day. Wait 24 hours if the floor is cold.
See the tooling range in our concrete grinding discs category.
What a Good Garage Prep Looks Like
- Uniform gray, no glossy patches.
- No visible oil stains.
- Cracks filled and flush.
- No trowel marks (especially on troweled new slabs).
Common Mistakes
- Grinding only the middle and forgetting the edges. Epoxy peels at the walls first.
- Using too fine a disc. 120 grit is the ceiling for epoxy prep.
- Not vacuuming enough. Garage dust kills epoxy adhesion.
Frequently Asked Questions
Q: Do I need to grind a new garage slab?
Yes. New slabs are usually troweled smooth and need a CSP 3 for epoxy.
Q: Can I acid etch instead?
You can, but grinding is more uniform and avoids acid disposal.
Q: How long after grinding can I park cars?
Wait 7 days for the epoxy to fully cure, even if it feels dry.
Conclusion
Garage epoxy lives on prep. Patch, 30/46 grind, 120 follow-up, vacuum, and coat the same day. contact JOY TECH for a starter tooling kit sized to your grinder.
