Cold Weather Painting

Not long ago, all it took was an unexpected cold front to throw a project off track: most exterior latex paints could be applied only at temperatures above 50° F. Painting contractors in the cold or mountainous regions of the West were used to curtailing their exterior painting seasons, turning down late season contracts and waiting until spring was well along before taking the ladders and brushes outside again. In fact, there are some places in the upper Northwest, where chill and damp are almost a year-around problem, making exterior work a very uncertain proposition, except in the warmest summer months.

Unpredictable weather can make deadlines hard to meet and keep work schedules in constant change, causing financial uncertainty and making late-season contracts a risky proposition. In addition, quality can suffer, because cold weather sometimes causes problems with latex paints regarding color development, gloss variations and delamination. What’s more, these problems are often not seen until the next time extreme weather causes stress to the surface. That’s when expensive callback lists begin to grow.

But thanks to a roster of cold-weather systems now available, a chill in the air no longer puts a damper on productivity. Specially formulated paints and primers engineered for temperatures as low as 35°F. have been available to painting contractors for a few years. These systems are now being joined by wood stains and concrete preparation products that can extend the application season and reduce cold-weather downtime on a wider range of substrates.

Not only do these cold-weather products perform well in chilly weather, they can also give good service under the moist conditions that winter brings, especially in the coastal regions. Cold-weather systems can be used for residential, commercial or institutional applications, and for both new construction and remodeling, allowing sales to be closed with confidence throughout the year.

Here are some general rules for cold weather painting using these new products:

1. If you’re painting a home or office building exterior, make sure that both the ambient temperature (the temperature of the air) and the substrate temperature (the surface to be painted) are 35° F. or above. Be aware that the early morning sun may make for ambient temperatures that top 35 degrees, but cooler night time temperatures from the previous evening may have chilled surfaces to be painted to less than 35° F. Alternatively, while all-day sunshine may warm surfaces, ambient temperatures may not get to 35° F. or greater. Under either of these conditions, painting can pose problems.

So when doing cold weather work on a house or commercial building, it might be useful to begin a little later in the morning, when the sun has had time to do its work, and to knock off a little earlier in the afternoon. And be sure to start the job in areas exposed to the morning sunshine, where the sun has had time to warm things up.

2. Be mindful of the dewpoint, too, that setpoint where air temperature and humidity meet to form moisture on surfaces. In colder weather, the humidity goes up as the temperature goes down, causing dewpoints to vary and moisture to form unpredictably. Moisture is a problem with waterborne paints at any time, but in cold weather it can easily become frost, hard to see but extremely detrimental to any painting project.

3. Because nighttime ambient temperature and substrate temperatures must not fall below 35° F. for two days after painting, pick exterior painting days with an eye to the weather forecast. Don’t paint on a day when a freeze is expected that night.

4. Use a system of products on your project that are all designed to be used together, products that can be applied easily and that are formulated to perform well in colder temperatures. That means not only paints, but also caulks and primers. These products must be compatible, to lessen any chance of poor intercoat adhesion and reduce the risk of performance failure.

5. Cold weather coatings are specifically designed to be used at lower temperatures without thinning, so never add anything to the paint such as antifreeze or other foreign substances. And make sure the product you choose to paint that apartment or store exterior is formulated to adhere to the surface being painted. It should also have the hiding characteristics you need to make application easy and fast.

6. Drying times are also critical. Among the paints, stains and primers developed for low temperature application, there are a wide range of times for given temperature levels. Use a product that has a drying schedule adequate to meet the needs of your residential or commercial job. Look for products that offer a fast drying time, especially considering the changeability of cold weather.

7. Be aware that new cold weather products can extend your scope services beyond the job of painting house siding to staining new and existing wood for homes or commercial buildings. With these new cold-weather products, you can take on more general contracting tasks such as caulking and preparatory work on concrete and other masonry surfaces, increasing your productivity and profit potential.

8. A note about storage: to preserve their performance and aesthetic integrity, store paints and related materials in a protected, heated environment, such as a cellar or basement, where they won’t be subject to freezing. While these materials are made to withstand a few freeze/thaw cycles, the products could have gone through some of these cycles while being transported, and too much cold can ruin paint.

By using these tips, painting contractors can take advantage of cold weather paint, prep and finish technologies. And by using cold-weather coating systems, contractors have a greatly extended painting season, with ease of application to reduce the workload. That helps meet deadlines — and improves bottom lines.

—Andrew Kinnen is architectural product manager for the Sherwin-Williams Company, Cleveland.