What should I ask about downtime before signing in Kanata?

A useful first downtime question: what does the data sheet for each product in this system say about return to service, and will the contractor commit to that schedule in writing before work starts?

Downtime is not one number. It has several parts that stack on top of each other, and a quote that gives only a single "back open in X days" figure is leaving things out.

Here is what to work through with the contractor before signing:

• Surface preparation comes first. Grinding, shot-blasting and crack repair happen before any coating goes down. That work produces dust and noise and may need the area cleared. Ask how many days prep takes on its own.
• Moisture testing adds time if the contractor follows ASTM F2170 or ASTM F1869 protocols. In-situ relative humidity probes under ASTM F2170 need to equilibrate in the slab before a reading is valid. Ask whether moisture testing is in the schedule and how long it adds.
• Ask for the return-to-service times from the data sheet of each product in the system. One manufacturer's data sheet for a 100%-solids epoxy lists foot traffic at 24 hours and heavy traffic at 7 days, at around 21 to 25 degrees C. A self-levelling urethane cement data sheet lists light foot traffic at 18 hours and heavy traffic and chemical exposure at 72 hours. A polyaspartic data sheet lists vehicles at 7 days despite a fast initial set. The data sheet for the specific product on your floor governs, not a general claim.
• Temperature matters. One epoxy data sheet says not to apply it below 10 degrees C, or when the surface is less than about 3 degrees C above the dew point. Ask what the contractor will do if the building is below the product's minimum.
• Phasing and after-hours work can shorten the closure if the floor is divided into sections or if coating happens overnight. Ask whether the quote includes phased or after-hours work, and if not, what that would add to the cost.
• Ask about ventilation. Some solvent-based primers may be flammable liquids; the Ontario Fire Code requires ventilation where flammable or combustible liquids are used, and the SDS Section 2 will say whether a product is a sensitiser or presents a vapour hazard. Ask for the SDS for every product before work begins.

Floor coating in an occupied commercial building is likely construction work under the Occupational Health and Safety Act. Before any contractor starts, obtain a WSIB clearance certificate and confirm it stays in effect for the full duration of the job.

The form on this page sends your request to local floor coating contractors, who reply by email.

Last, ask the contractor to show you the line in the quote that covers what happens if the moisture test comes back above the product's limit, because a moisture-mitigation primer or a system change can add cost that a tight initial number does not include.