When is it Too Hot to Paint Outside?
Atmospheric temperatures have little to do with exterior paint applications. Although, surface temperatures should never exceed 95 degrees when painting with water-based acrylic house paints.
Water-based paints will lose adhesion and could blister and bubble on surfaces reaching over 100 degrees. However, high-heat exterior oil paints can reach application temperatures ranging from 120 – 150 degrees Fahrenheit and withstand temperatures over 300 degrees once dry.
Painting When It’s Too Hot
Painting, when it’s too hot, can cause adverse effects on the paint coating. Still, how most gauge hotter temperatures is often inaccurate in determining when it’s actually, “too hot to paint.”
Painting in warmer conditions is advantageous as the surface is more prone to being dry, and the paint will cure faster. While painting under any extreme temperature is never ideal, just because it’s hot outside doesn’t mean you can’t paint.
There are ways to even work within extreme temperatures efficiently and effectively. Therefore, just because the weather is seemingly unbearable doesn’t mean your painters are doing something wrong and should not paint under such conditions.
Painting In 100 Degree Weather
The angst of someone without experience is natural and to be expected. The misconception is that you should never paint in 100-degree weather. But the reality is that paints have additives that help them perform better in hot temperatures. There are exterior house paints engineered and explicitly designed for hotter climates. But even those paints have temperature limitations.
High levels of paint surfactants assist paint applications, but measuring the surface temperature is the fundamental way to determine if it’s hot. If you don’t have a means of precise measurements, an easy way to gauge a paintable surface temperature is cautiously by touch.
Painting In the Sun
Painting directly in the sun when the sun has radiated on a surface for a long time is a sure way to ask for trouble. Most exterior painters will paint chasing the sun, meaning starting on the shady side and following the sun without painting directly in it.
If chasing the sun is not an option, pay attention to how the paint applies. If the paint is steaming or the surface cannot be touched for more than 5 seconds, it’s too hot unless you use oil-based paint.
Paint Drying in Hot Weather
Hot weather will undoubtedly create challenges for inexperienced exterior house painters. Dark colors will often dry too quickly, causing lap marks. The paint will also dry faster.
When rolling or spraying, the paint often leaves more texture during hot days or under direct sunlight. Brush strokes will be more prominent when under high heat, resulting in high-attention focal points, such as front doors, with a less professional-looking finish.
The Sun Making Paint Dry Faster
Sometimes the sun is needed for painting to prevent the paint from dripping and creating what painters call “paint runs.” We use this term often as checking for paint runs before they dry can be challenging, even for us.
Regardless of the needs, experience using the paint product and painting professionals will help to understand each situation’s requirements. It would be unfair to generalize all quick-drying paints as lousy applications, as each project need differs.
Paint Solvent Evaporation Advantages
The paint solvent must evaporate for the paint to dry, and this process is a valuable component of house painting.
Evaporation happens when the solvent, being either water or mineral spirits, goes from an area of high moisture, dissipating and transferring into the air, typically an area of less moisture. And moisture transfer does work best in hotter climates.
Application Recommendations
- A Purdy Pro-Extra is the best paint brush for hot weather.
- Use a 5 17 paint spray tip or larger to prevent lap marks when painting in the heat.
- Use a 3/4” roller nap or greater when rolling paint outdoors on larger surfaces.
