Before signing, which prep questions should I ask in Ottawa?

Surface preparation is the part of a floor coating quote that is easiest to leave vague, so put these questions to the contractor in writing before you sign.

Start with what is on the slab right now. Ask the contractor to identify every existing coating, adhesive or surface treatment and explain how they plan to remove it. Old vinyl tile and black mastic may contain asbestos, and under the Occupational Health and Safety Act s.30(1) you, as the owner of the project site, must determine whether any designated substances are present and give a prospective contractor that list before a binding contract is signed. Have old tile or mastic tested before any grinding begins. If you do not have test results, say so in writing before the contractor starts.

Ask specifically about the surface profile the contractor is targeting and how they will achieve it. The ICRI concrete surface profile scale runs from CSP 1 to CSP 10; data sheets for different systems ask for different profiles, so ask which method the contractor will use to reach it, shot blasting or diamond grinding, and how they will control the dust. Ask whether the prep cost is included in the square-foot price or quoted separately. Published 2025-2026 contractor ranges put standard prep at roughly $1 to $3 per square foot when it is broken out, and heavy resurfacing of damaged concrete costs more than that, with no published ceiling.

Ask about moisture. The contractor should test the slab using ASTM F2170 (in-situ relative humidity probes) or ASTM F1869 (calcium chloride vapour emission), and the results should be in writing before any coating goes down. Ask what happens if the slab reads above the limit on the product data sheet: will they use a moisture-tolerant primer, and what does that add to the cost? Ask the same question about cracks and joints: are repairs included, or are they a line item that appears after grinding reveals them?

A few other questions worth putting in writing before you sign:

• What is the exact closure window, in hours, based on the data sheet for the specific product being applied, not a general estimate?
• Will work happen after hours or in phases to keep part of the facility open, and what is the cost of that?
• Does the quote include cove base, anti-slip broadcast, or safety line striping, or are those separate?
• Can you see the product data sheet and the safety data sheet for every material being applied? Under OHSA s.38(1.1), your workers who remain on site during coating work must have access to those SDSs.
• Do you have a current WSIB clearance certificate? Under WSIB policy 14-02-19, you must obtain and hold a clearance before work begins, and you can be held liable for the contractor's WSIB obligations if you do not.

If the floor is in a food premises, ask Ottawa Public Health before booking whether your planned re-floor counts as a significant renovation requiring their notification.

One line in a floor coating quote where extra cost can hide is the one that says "surface preparation included" without specifying the method, the target surface profile, and whether crack repair, adhesive removal and moisture mitigation are covered or billed separately once the floor is ground and inspected.