Temperature & Humidity vs. Paint

Rain and wind are not the only environmental factors that affect ideal painting conditions. Homeowners, contractors and handymen must contend with temperature and humidity, too, during exterior projects. Painting under the right conditions can make the difference between a job well done and a redo. Read on to learn about the ideal circumstances for painting to avoid any unwanted issues.

How Temperature Affects Drying

Why does temperature matter? When painting a house, temperature is a huge factor in how fresh paint dries. Drying paint in temperatures that are too low or high could result in cracking and peeling. For example, extreme cold can prevent paint from drying properly because moisture inside the formulation can freeze before it cures completely. On the other end of the spectrum, extreme heat can evaporate moisture in the paint too quickly. This can cause the top layer of paint to skin over before the layers underneath dry, which can produce cracking, blisters and other imperfections.

There are some rules of thumb to follow when it comes to different types of paint. Temperatures above 45 degrees Fahrenheit are recommended when using solvent or oil-based paints. Latex and acrylic paints dry much better in temperatures that exceed 50 degrees Fahrenheit. If temperatures dip, dew can form on surfaces and cause the water in the paint to evaporate too slowly. Some paints are now formulated to dry at lower temperatures, such as 35 degrees Fahrenheit. It’s vital to follow the instructions on paint containers, since each paint formula is designed to be used within specific temperature and humidity parameters.

How Humidity Affects Drying

When high-humidity conditions are combined with low temperatures, the protective qualities of paint may be compromised. Condensation can occur on the paint’s surface, which creates issues with the paint’s drying and adhesion. In some cases, high humidity can cause unsightly streaks or surfactant leaching, which is a brown or white discoloration on the surface of the paint. Additionally, excess moisture in the air can be absorbed into wood surfaces and affect paint adhesion. This can result in bubbling or peeling paint.

Avoiding Problems 

Be sure to check the weather forecast before starting any outdoor painting project. It’s also a good idea to monitor the temperature and humidity levels during painting projects. The best time to paint, depending on geography, would likely be early summer or fall. These seasons usually offer the best weather conditions, with minimal rain and fluctuations in temperature from day to night. This can ensure that the paint adheres smoothly and has a chance to dry and cure properly. Summer also tends to be the ideal time for painting since it is typically dry and warm. Aim to paint when you have a day with low to moderate humidity, no wind and temperatures ranging between 60 and 85 degrees Fahrenheit.

Sticking to these guidelines can help you end up with a flawless finish. Before you get started on your next painting project, take a look at the accompanying infographic to review how temperature and humidity can affect a fresh coat of paint.

 

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