Prepare concrete to the CSP profile required by the coating data sheet, using the ICRI 310.2R scale: grinding gives the finest profiles and suits thin films and edges, shot blasting covers the middle range on large horizontal areas, and scarifying produces the heaviest profiles for thick systems or removal of old coatings. In every case, silica dust is captured at the source.
Most industrial floor failures do not come from the product but from preparation: laitance left in place, a profile that is too smooth, a contaminated or dusty surface. Mechanical preparation removes the weak layer, opens the concrete and creates the anchor the coating needs. This guide is written for maintenance managers and project managers of plants and warehouses in Quebec and Ontario. It follows our guide to concrete repair before coating, because repairs come before final preparation.
What is the ICRI 310.2R CSP profile?
The CSP (concrete surface profile) is a roughness scale for concrete running from CSP 1, nearly smooth, to CSP 10, very rough. ICRI 310.2R defines it with moulded reference chips, against which the prepared surface is compared by sight and touch.
ICRI 310.2R also links each preparation method to the range of profiles it can produce. SSPC-SP 13 / NACE 6 completes this framework for concrete preparation before coating, and ASTM D4258 (cleaning) and ASTM D4259 (abrading) describe the methods. Profile is only one criterion: the surface must also be sound, clean, dry and free of laitance.
Which CSP profile does each coating need?
The required profile rises with system thickness: a sealer or thin coating needs a low profile, a thick coating or self-leveller a medium profile, and a screed or mortar a heavier one. The exact value is always the one in the manufacturer's data sheet and the project specification.
Two mistakes are common. A profile that is too low under a thick system limits mechanical anchoring and promotes debonding. A profile that is too high under a thin film leaves peaks uncovered and uses more product with no adhesion gain. The choice of floor system, covered in our guide to industrial floor coating types, therefore comes before the choice of preparation method.
Shot blasting, grinding or scarifying: which method?
Choose the method by target profile, area, concrete condition and what must be removed. The table below summarizes trends; ICRI 310.2R gives the profile ranges for each method.
| Method | Profile achieved (relative) | Typical uses | Limits |
|---|---|---|---|
| Diamond grinding | Low | Thin films, edges, light flattening, removal of thin films | Can polish the concrete with the wrong tooling, slow on large areas |
| Shot blasting | Low to medium, adjustable | Large horizontal areas, laitance removal, medium to thick systems | Cannot reach corners, striping if poorly set, sensitive to damp surfaces |
| Scarifying | Medium to high | Removal of thick old coatings, very thick systems, uneven surfaces | Very irregular surface that may need resurfacing, vibration and noise |
| Abrasive blasting | Low to medium | Vertical surfaces, complex shapes | Heavy dust and containment, see abrasive blasting |
| Hydro blasting | Medium to high | Removal of deteriorated concrete without microcracking | Water management, drying before coating, see hydro blasting |
Acid etching is not in this table: it removes neither oils nor old coatings, leaves residues that must be neutralized and makes the profile hard to control. It is rarely chosen in industrial settings.
When is shot blasting the best method?
Shot blasting is the best method on large, dry, clear horizontal slabs that will receive a medium to thick system. The machine throws steel shot at the concrete, recovers it and vacuums the dust in a closed loop, so the work is fast and clean.
The profile is set by shot size, travel speed and number of passes. A trial pass on a test area, compared with the CSP chips, fixes these settings before the whole surface is treated. The limits: the machine cannot reach corners, wall lines or equipment plinths, which are finished by grinding; it handles damp or oily surfaces poorly, so they are degreased first; and an aggressive setting can expose aggregate or leave striping.
When should grinding or scarifying be preferred?
Prefer grinding for fine profiles, edges and small areas, and scarifying when a significant thickness must be removed: a thick old coating, deteriorated surface concrete or major irregularities.
- Grinding. Diamond discs abrade the surface. It is the method for edges, steps, congested areas and thin films. Grit and tooling are chosen to open the concrete without polishing it: an over-polished surface hurts adhesion.
- Scarifying. Rotating cutters strike the concrete. The method removes thick coatings and deteriorated layers quickly, but leaves a grooved surface that often needs an underlayment or a thick system to even it out.
On the same job, methods are often combined: scarifying of deteriorated zones, shot blasting of large areas, grinding of edges. The aim is a uniform profile across the whole surface, including repaired zones, so the coating behaves the same everywhere.
How do you control silica dust during preparation?
Control silica dust at the source: vacuum built into the machines, high-efficiency filter dust collectors, enclosure of work zones and suitable respiratory protection. Crystalline silica released from concrete is regulated provincially, by the RSST in Quebec and the designated substances regulation in Ontario.
Common measures:
- Source capture. Shot blasters and grinders connected to a dust collector sized for the machine; dry sweeping is not allowed.
- Enclosure. Tarps and temporary walls to isolate the zone from production, especially near sensitive equipment or food.
- Worker protection. Respiratory protection selected from the exposure assessment, and decontamination areas.
- Waste management. Dust and old coatings bagged and disposed of according to their nature, for example if they contain metals.
Our article on blasting in operating plants and dust control details these measures in a running facility.
How do you check that a concrete surface is ready?
A surface is ready when its profile matches the target CSP chips, laitance and contaminants are gone, dust has been vacuumed, moisture is within the coating's limit and surface strength is adequate. These checks are recorded before application.
- Profile. Comparison with the ICRI reference chips at several locations.
- Cleanliness. No laitance, oil, stains or dust; a simple water drop test spots areas that do not absorb.
- Moisture. Tests using the methods in our article on concrete moisture before coating.
- Surface strength. Pull-off testing to ASTM D7234 if the concrete looks weak or the specification requires it.
- Timing. The coating follows preparation before the surface becomes contaminated again.
How do you plan preparation and get a quote?
Plan by fixing the coating system first, and therefore the target profile, then the method by zone, dust control and phasing with production. Preparation takes a large share of site time: it is planned, it cannot be made up later. A good preparation plan states, for each zone, the method, the target CSP, the dust control setup, the acceptance checks and who signs off before the coating crew starts.
Our industrial epoxy flooring service includes mechanical concrete preparation, and our protective coatings offer applies it to concrete basins, pits and walls as well. Our crews and qualified subcontractors work from LaSalle, including in Laval, in Montreal and in Ontario. Send photos, the areas, the current floor condition and the shutdown window through the quote request: pricing on consultation, reply within 24 business hours.
Frequently asked questions
Is shot blasting enough for every floor coating?
No. It suits large areas and medium to thick systems well, but edges are finished by grinding, and very thick systems or thick old coatings may call for scarifying.
Is washing enough before coating concrete?
No, not for an industrial coating. Washing neither removes laitance nor creates a profile; mechanical preparation matched to the required profile is needed.
How is a CSP profile measured on site?
By visual and tactile comparison with the moulded reference chips of ICRI 310.2R. Several areas are compared, including edges and repaired zones.
Can preparation be done while the plant is running?
Often, yes, in enclosed zones with effective dust capture. Phasing, noise and vibration are coordinated with production before work starts.
Hicham M, P Eng, PMP
Engineer and project manager (PMP) at Induscoat. Over 16 years of experience in industrial coatings, composite repairs and wear protection on mining, energy and petrochemical sites in Canada and internationally.