Surface prep is the single biggest predictor of whether a floor lasts twenty years or fails in eighteen months. Get the profile wrong and even the best 100% solids epoxy system will lift inside a year. Get it right and you can pour our EP-100S over a polished slab and walk away.
Two methods dominate concrete prep for industrial coatings: shot blasting and diamond grinding. Both create surface profile. Neither is universally correct.
CSP — what we're actually targeting
The International Concrete Repair Institute publishes nine Concrete Surface Profile levels, CSP 1–9, from a smooth steel-troweled finish (CSP 1) to scarified concrete (CSP 9). For coatings work, you almost never go past CSP 4.
Your topcoat thickness picks the profile:
| Topcoat thickness | Target CSP | | --- | --- | | ≤ 6 mil (sealer) | CSP 1–2 | | 6–10 mil (single-coat epoxy) | CSP 2–3 | | 10–25 mil (build coat + topcoat) | CSP 3–4 | | 25 mil+ (mortar, broadcast systems) | CSP 5–6 |
Diamond grinding
Best for: clean slabs, no contamination, profiles up to CSP 3.
A planetary grinder with metal-bond diamond tooling cuts a controlled, even profile. It's quieter than a shot blaster, kicks less dust if you have HEPA, and you can dial the aggression by swapping diamond grits.
Where it falls down: hard slabs (the diamonds glaze), oil-soaked slabs (the contamination smears around), or whenever you need a CSP 4+ profile. You'll spend three times as long getting there as a shot blaster would.
Shot blasting
Best for: large open areas, contaminated slabs, CSP 3–6 profiles.
A shot blaster fires steel media at the surface and recovers it on the same pass. It produces a deeper, more uniform profile than grinding and is significantly faster on big square footage. It also opens the pore structure, which is what you want when you're about to pour 25 mil of build coat.
Where it falls down: anywhere you can't move the machine. Stairs, edges within 4", transitions to wood or tile. You'll need a hand grinder for those regardless of which method you pick for the field.
The four spec calls we get most often
- Garage floor over a 5-year-old slab → diamond grind to CSP 3. Shot blast is overkill, slower, louder.
- Warehouse, 20,000 SF, oil-stained → degrease, then shot blast to CSP 4. Grinder smears oil into the profile.
- Showroom over polished concrete → grind, CSP 2, careful etch. Shot blast destroys the polish you're trying to use as a substrate.
- Slab-on-grade with 9 lbs MVT → grind, CSP 3, prime with PR-510. Either method works, but grinding leaves less debris to vacuum out before priming.
The rule of thumb
If your topcoat is < 10 mil, grind. If it's > 15 mil, blast. If it's in between, it's a judgment call that depends on slab age and contamination — and that's when you call us.
What we sell
Resin Source supplies the diamond grit and the shot media — both manufacturer-direct. We don't rent grinders or blasters ourselves, but if you need a referral to a Texas tool-rental partner inside our 200-mile delivery zone, hit the quote desk and we'll point you at the right shop.