Winter installations are possible and common in Calgary, but they are not the same as summer installations. Temperature control, product selection, and timing change significantly. Do it right and the floor is indistinguishable from a summer install. Do it wrong and it fails before spring.
Epoxy is a thermally driven chemical reaction. The resin and hardener molecules have to move and bond at a molecular level. Cold slows that motion. Below about 10 degrees Celsius, the reaction slows dramatically. Below 5 degrees, the reaction can stall entirely. A base coat applied to a slab at 0 degrees Celsius can remain soft and uncured for days, picking up dust and contamination. A base coat applied to a slab at -5 degrees Celsius might never fully cure. The distinction matters. A soft, uncured surface creates a weak substrate for the topcoat. The topcoat may adhere poorly, or the system may fail entirely at the adhesion layer between base and top.
For any installation below 10 degrees Celsius ambient, we run propane heaters or temporary HVAC in the garage for a minimum of 12 hours before the coating day begins. One heater is not enough. The thermal mass of concrete is large. A 40,000 BTU heater in a 400-square-foot garage can raise the air temperature to 15 degrees Celsius in two hours, but the slab may still be at 5 degrees Celsius. We run continuous heat for the full preheat window. The heater stays running through the application day and into the cure window. We check slab temperature at multiple points with a calibrated infrared thermometer within 30 minutes of application time. If any point on the slab reads below 10 degrees Celsius, we do not coat. The work gets delayed.
Standard epoxy base coat is formulated for a temperature range of about 15 to 25 degrees Celsius. Outside that range, the pot life (the working time) changes. For winter installations below 10 degrees, we use an epoxy base coat formulated with a cold-weather accelerator. The accelerator is a chemical agent that speeds up the polymerization reaction, compensating for the temperature deficit. A pot of standard epoxy might give you 30 to 40 minutes of working time at 20 degrees Celsius. The same product with accelerator might give you 12 to 18 minutes at 5 degrees Celsius. This is not a problem if you understand it and plan for it. It is a major problem if you treat winter application the same as summer application.
Standard polyaspartic topcoat is formulated to cure fast. At 20 degrees Celsius, a polyaspartic topcoat might be tack-free in four to eight hours. That fast cure is an advantage in warm weather. In cold weather, it is a liability. Fast-curing polyaspartic at below 10 degrees Celsius can gel before it levels itself out, trapping lap marks, brush strokes, and uneven sheen into the finished surface. For winter topcoat applications, we use a slow-cure polyaspartic formulation. This extends the working time and levelling window. The product stays workable long enough to achieve proper levelling before it kicks. Cure time is longer overall, but the final finish is correct.
This is the problem no one thinks about until it costs them. In late fall and early spring, when outdoor temperatures swing from below freezing in the morning to above freezing in the afternoon, condensation forms on cold surfaces. A concrete slab that is colder than the dew point of the surrounding air will have surface moisture. This moisture might not be visible to the eye. It is there. We check for it using moisture meters and by assessing the slab temperature against the ambient dew point. If there is any visible moisture, or if the slab is within a few degrees of the dew point, we do not coat. We wait for conditions to improve. This has delayed jobs by days. It is worth it. Moisture under a coating is bond failure waiting to happen.
Now put it into action. Get a real price on your Calgary epoxy floor in under two minutes.
