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

1. Clean the floor. Degrease oil spots; they prevent adhesion.
2. Patch cracks and spalls with epoxy mortar. Let cure 24 hours.
3. Edge grind first with a 5-inch cup wheel. Then the big grinder does the middle.
4. Grind with 30/46 grit metal bond. Our double-S segment discs works on most push grinders.
5. Second pass at 120 grit to remove the heavy scratches.
6. Vacuum twice. Wipe with a damp microfiber cloth to catch fine dust.
7. 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.