Surface Preparation and Grinding

Shot blasting propels steel media in a closed machine to remove laitance and leave a uniform open texture for coatings and membranes. Diamond grinding abrades with bonded segments and is better for high spots, thin coatings, adhesive, and controlled smoothing. Harrowgate often combines methods because open fields, edges, and thick defects require different tooling.

Acceptance uses the specified profile, complete removal of contaminants and weak material, cleanliness, moisture result, and tensile pull-off where required. A uniform appearance is not enough. Harrowgate produces a mockup, compares the production surface, repairs defects, and obtains consultant or manufacturer acceptance before primer or coating covers the concrete.

Grinding removes contaminated surface concrete, but oil can penetrate deeper and migrate back. We identify the extent, use approved cleaning or poultice treatment where specified, remove affected concrete, and perform adhesion trials. Severely saturated areas may need deeper replacement or a compatible mitigation system rather than repeated shallow grinding.

Yes, disturbing concrete can release respirable silica. Harrowgate uses effective on-tool vacuum extraction, sealed work zones, maintained filters, controlled waste handling, and Ontario-required exposure controls. Dry sweeping and uncontrolled compressed air are not used. Wet methods are selected only when slurry can be fully contained and the next flooring system permits moisture.

Grinding can remove measured high spots and reduce joint lips or local transitions. It cannot raise low areas and may be limited by slab cover, thickness, embedded systems, drainage, and required finish. Harrowgate surveys the floor and combines controlled removal with repairs or toppings where the tolerance cannot be reached by grinding alone.

The floor may have been polished too smooth, left dusty, contaminated below the surface, too moist, or covered after the preparation window. Weak concrete can also remain beneath a clean face. Harrowgate selects tooling from a mockup, vacuums thoroughly, tests pull-off and moisture, and protects the accepted surface until primer is applied.

Smaller shrouded grinders, hand tools, and localized blasting prepare edges to a profile compatible with the open field. Harrowgate works around columns, curbs, drains, joints, walls, and equipment without leaving a smooth perimeter strip. Edge dust is extracted and the transition is inspected under the same acceptance criteria as the main area.