When There is No Choice
Most contractors try to plan outdoor painting projects for warm weather, but sometimes you have no choice. When talking about painting in cold weather, we’re defining “cold” as anything below 10°C (50 degrees Fahrenheit). If you don’t have any alternative to painting in cold temperatures, don’t worry, it’s still possible, you just need to follow a few simple steps.
How the Cold Effects Paint?
Temperatures below 10°C can negatively affect your paint and your application. Alkyd and oil-based paints thicken up in cold weather because they are made from oils and resins that change viscosity with varying temperatures. Painting smooth and even is much harder with thick, slow moving paint. Latex paints are water based, and therefore susceptible to freezing in the cold. There are some anti-freeze paint additives that can be mixed with paint, but the best situation is warmer temperatures.
All paints are formulated and designed to cure within a specific temperature range, if you paint outside that designed temperature the paint may not cure or bond properly. Without curing you can get poor coverage, blushing, peeling, bubbling, cracking, low sheen, and color inconsistency.
Can You Use Paint Once It Has Been Frozen?
Not a good idea, especially if it’s been frozen more than once. If the paint is inconstant in texture and no longer has a smooth consistency, don’t use it! The freezing process has changed the chemical structure of the paint and prevents emulsification. Meaning; it will no longer cure properly. Oil paint freezes at lower temperatures than latex but is more likely to spoil in cold storage.
Caution About Paint Coating in the Cold
The drying time in cold weather is much greater for both oil and latex. Therefore, your next coat of paint should be spaced a bit further than normal. For example, painting with latex at 24°C (Ideal painting temperature), the next coat can go on after a 2-4 hours. But when the temperature is below 10°C, the initial coat won’t cure or dry for more than 6 hours. Painting in the cold with oil paints needs even more time. Some situations require more than 48 hours before recoating. To prevent problems, always follow the manufacturer’s instructions for recoat times.
Surface temperatures can also be significant variables. Direct sunlight or shade can cause surface temperatures to vary between different areas on the same surface. Understandably, drying times and recoat times are affected by inconsistent surface temperatures.
Cold Weather Paint
Some paints are designed for cold weather. Most of these are rated for temperatures above 2°C. Use cold temperature paint if you can’t wait for warmer weather. Paint designed for lower curing temperatures are better than standard paints mixed with anti-freeze additives. Remember to check the paint manufacturer’s instructions. Never paint below or above the minimum recommended curing temperature during the entire curing process, not just during application.
Surface Temperature the Key
When we say “minimum recommended curing temperature” it means both the air and the surface you paint on. The wall or ceiling surface can be much different than the air, and the opposite can be possible as well.
Infrared thermometers are a great tool to get accurate temperatures if you’re worried about hot or cold surfaces.
Hope your painting project goes well and your fortunate enough not to have to fight winter like us. But if your painting in the cold at least now you might have a chance of better results. Happy painting Canada!
Pesada has been painting industrial and commercial buildings in Ontario, Canada since 1975. Read more from The Pesada Painting & Coatings Corporation