Concrete Floor Preparation in Guelph

Why the bond line matters more than the sheen

A coating sticks to the surface it actually touches. Laitance, dust, curing compound, tile adhesive, and a chalking sealer are all surfaces, and they are weak ones. If they stay, the new film bonds to them and leaves with them. Grinding or blasting is how professional crews remove that layer and open the concrete paste so the primer can wet it. Acid etching shows up in old instructions and in retail kits. It is a poor substitute on many modern slabs, it is difficult to neutralize and rinse indoors, and it is not the preparation a careful quote should treat as the default.

You should see preparation as a deliverable: a method, a target profile, and a clean, vacuumed surface before resin is mixed. “Scuff and coat” can be enough for a compatible recoat over a sound film. It is not enough for bare, hard-troweled, or contaminated concrete. Peeling is the usual price of skipping this step.

Grinding and shot blasting

Diamond grinding uses rotating tooling to cut the surface. It is common in garages and interior rooms because the machine size fits through a door and, with a shroud and vacuum, it controls dust better than an open grinder. Different grits and tooling change both the profile and how quickly the work goes. A light grind that only polishes the paste is not the same service as a grind that removes a coating.

Shot blasting throws steel shot at the slab and recovers it. It is efficient on open commercial and industrial floors and can produce a uniform profile without the swirl a grinder can leave. It needs clearance and a slab that the machine can travel. Edges, corners, and areas under equipment still get hand work. ICRI Guideline 310.2R describes preparation methods and the concrete surface profile chips people use to talk about roughness, from a nearly smooth CSP 1 up through aggressive repair profiles. Coating data sheets name the CSP range they want. The quote should echo that range instead of saying “roughened.”

Oil, sealers, and old coatings

Petroleum stains can sit in the pores after the surface looks clean. Some crews use a degreaser and then grind; some grind until the stained paste is gone; some will exclude a saturated area rather than promise a bond. Ask which approach is in the price. A visible stain that remains is a risk you should hear about before you pick a colour.

Existing epoxy, paint, and tile adhesive are removal jobs when they are unsound. A sound, well-bonded coating can sometimes be prepared and recoated if the new product says it can go over that existing film. The test is adhesion, not optimism. Repair or recoat and floor repair cover that fork. Tile mastic and cutback adhesive can be stubborn and, on older floors, may raise hazardous-material questions that a coating crew should not guess about. If you suspect old adhesive of that kind, say so.

Repairs that belong in the prep scope

Cracks, spalls, and joint edges are often repaired after the surface is opened and before the body coat. The filler has to be compatible with the coating and with whether the crack is moving. Rigid filler in a moving garage joint is a frequent cause of a straight crack showing up in a brand new floor. Cracked concrete is the longer explanation.

Preparation does not include secretly rebuilding a slab. Large areas of delaminated concrete, exposed corroded reinforcing, or heaved panels are repair projects with a different risk. A fair quote separates “grind and coat” from “remove loose concrete and patch.” Dust control, plastic protection for walls and furnaces, and who disposes of the slurry or vacuum waste should also be clear. Coating dust and resin are not household sweepings. Crews should follow equipment controls and the chemical safety guidance that applies to the products they bring on site.

How preparation should read on a quote

If prep is buried inside a single price, you cannot tell whether a lower number skipped it. Ask for it as its own description even if the dollar figure is combined. A visit is the right time to confirm hardness, old coatings, and access. Photos help, but they do not show how thick an old film is.

• Method: grind, shot blast, or a combination, plus edge work
• What will be removed: sealer, paint, adhesive, or a failed coating
• Target surface profile, tied to the coating data sheet
• How oil-stained areas will be treated or excluded
• Crack and joint work, listed rather than implied
• Vacuum standard and protection of the rest of the room
• Whether moisture testing is included or assumed unnecessary
• What the coating warranty, if one is offered, requires of this prep