Measure the slab, not the forecast
A concrete slab has enormous thermal mass, so it follows air temperature slowly and roughly a day behind. A garage that reads 12°C on the thermometer after a warm afternoon can easily have a slab still sitting at 6°C from the cold night before, which is below the epoxy cure threshold. We take an infrared reading of the concrete itself on arrival, and that number decides whether the day goes ahead.
The dew point rule nobody mentions
This is the failure that catches inexperienced crews. If the slab temperature is within 3°C of the dew point, there is an invisible film of condensed moisture on the concrete, and resin applied over it does not bond. The floor looks perfect on handover and lifts within months. It is entirely preventable with a $40 hygrometer and the discipline to stop when the numbers say stop, which is a decision made on the morning rather than at the quote.
What happens if epoxy cures cold
It does not simply cure more slowly. Below its threshold, an epoxy cures incompletely, producing a soft, sometimes tacky film that never reaches its designed hardness or chemical resistance. It may also amine blush, a waxy haze that forms as the amine hardener reacts with moisture and carbon dioxide, which blocks adhesion of the next coat. Neither is repairable by waiting. The floor has to come off.
How we keep working through an Interior winter
Three ways. Polyaspartic systems cure near zero and cover most shoulder-season work. Heated enclosures with indirect-fired heaters bring a slab up over a day or two, which is worth doing on a large commercial floor and rarely on a single garage. And for attached heated garages, the season is irrelevant. What we will not do is coat a cold slab and hope, which is the actual reason some quotes are cheaper in February.
Want this answered for your slab?
Free site visit with a moisture reading, then a written fixed price. Across the BC Interior.