Preparation decides whether the floor lasts
Almost every failed coating we're called in to replace failed at the same point: the bond. Not the product, not the color, not the topcoat — the interface between concrete and coating. Which means the most consequential decision on a floor job happens before any resin is opened.
There are two serious methods for opening up a slab: shot blasting and diamond grinding. They do different things, and the choice isn't a matter of preference.
What shot blasting does
A shot blaster fires steel shot at the slab at high velocity inside a sealed housing, then recovers the shot and the debris in the same pass. The result is a uniformly textured, open surface with dust captured at the source.
Our machine of choice for this is the Bartell Morrison Shotblaster Hornet — a 2.8 hp unit running on 110V. The power requirement matters more than it sounds: on residential and light commercial sites, standard building power means no generator, no cabling across a working space, and no waiting on an electrician.
Shot blasting is the right call when:
- The area is large and open, and speed per square foot is the constraint
- An existing coating or sealer needs to come off across the whole floor
- A uniform, aggressive profile is needed for a thick-build or moisture mitigation system
- Dust containment matters in an occupied building
What diamond grinding does
Grinding removes material with rotating diamond segments and gives finer control over the finished profile. It reaches edges, corners and detail work a blaster physically cannot, and it can take a slab from aggressive removal down to a polish depending on the tooling.
Grinding is the right call when:
- The slab is uneven and needs flattening, not just texturing
- Glue, mastic or a soft coating would blind a blaster's shot
- Edges, corners and stem walls need to match the field
- The specification calls for a specific concrete surface profile with tight control
On most of our projects the answer is both: blast the open field for speed and uniformity, grind the perimeter and details so the profile is consistent everywhere the coating lands.
Profile is a specification, not a judgement call
Concrete surface profiles are defined on a scale from CSP 1 (barely textured) to CSP 9 (heavily scarified). Coating manufacturers state a required profile for each system, and warranty coverage assumes it was achieved.
For the flake and polyaspartic systems we install, that generally means CSP-3. It's why we don't acid etch — etching cannot produce a consistent mechanical profile, and a floor prepped that way is where hot-tire pickup usually begins.
Why prep carries extra weight in South Florida
Preparation is also when the slab tells you what it's hiding. Once a coating or sealer is removed, moisture testing can actually be performed — ASTM F1869 for vapor emission or F2170 for in-slab relative humidity.
In a region where slab-on-grade construction sits close to the water table and older slabs frequently have no vapor barrier, that test result changes the entire system specification. Prep first, test second, specify third. Reversing that order is how a beautiful floor turns into a warranty claim eight months later.
How a typical day runs
A three-person crew moves through it in sequence: one prepares and protects the space, one runs the blaster across the open field, one follows with the grinder on edges and details before coating begins. Each stage gets checked before the next starts, because nothing downstream can fix a profile that wasn't achieved.
That's the unglamorous half of the job. It's also the half that determines whether the floor is still intact in ten years.
