Best Days for Exterior Painting
In the construction industry, we're often faced with schedule-wrecking weather interruptions. Two trades hit the hardest by Mother Nature are roofing and painting. While roofing can still be done (though uncomfortably) when it is really hot or extremely cold, painting requires a narrower range of temperatures for the best results.
Best Weather Conditions for Exterior Painting
James Hardie Building Products, a large manufacturer of siding and building components, conducted a study in the Houston area a few years ago. They found that less than 1/3 of the year provided optimum conditions for painting a home exterior. This was based on temperature, humidity, rain and a handful of other factors. According to the study, “when the weather conditions are taken into account, finding days with ideal paint conditions can pose a big challenge. Because of the extreme heat, July and August are the least ideal months to paint. Additionally, days when the weather is agreeable are often spread out, meaning that a house could sit half painted for weeks or even months.”
What is the best temperature to paint your house? If you'll be using latex paint, it's between 50 and 85 degrees Fahrenheit. For oil-based paint, think 40-90 degrees. In terms of relative humidity, 40-70 percent is ideal for drying paint.
Prefinished is an Option
Weather conditions like those found in Houston and other areas, have led to an increase in products that are available prefinished. High winds, pollen and dust can also compromise a painting project. Applying the finish in the controlled environment of a factory ensures that the paint is ready to perform at its best.
Many Hands Can Speed the Work
If the James Hardie study had been completed here in Colorado, I’m sure the number of days that are ideal to paint would fall even further. As a DIY homeowner, you'll find some complexities of scale added to the task of painting your own house. How much can one person paint in one day with a simple brush or roller? Most likely a lot less than an experienced crew with many brushes and rollers, or even spray equipment. Often hiring a painting contractor, who has the ability to tackle a large project with a full crew and professional equipment, can often make the best of short windows of opportunity, and can help you to avoid pausing a paint job.
Best Times to Paint by Region
- The South Atlantic Region: Eastern Texas, the Gulf states and up to the Carolinas are classified as humid–sub tropical, which means that humidity is pretty constant. In these areas, late winter usually provides the reduction in humidity that allows for successful painting.
- The East South Central Region to the Mid Atlantic Region: This region is humid continental (warm summers) and like the South, late winter and spring provide less humidity. The late summer provides a window of great painting time. Working around rainstorms may be challenging, but this area does offer late-summer respite from the South’s hurricane season.
- The West North Central Region: This region is the humid continental (cool summer) zone. This zone offers many days in the summer where temps and humidity levels are great for painting.
- The Mountain Region: Large areas of semi arid steppe provide great conditions for painting all summer.
- The Desert West Region: This region may get too hot in the summer for ideal panting, but with warm winters, it is not uncommon to find ideal days in the spring or late fall.
- California: It’s mostly a Mediterranean climate and yields one of the widest ranges for great weather and painting.
- Pacific Northwest: The coastal northwest is rainy throughout much of the year, but summers provide the warmth and dry spells needed to get great results.
Coping with Heat
I have experienced surface temperatures of siding in excess of 130 degrees on sunny exposed areas even though the air temp is in the mid 70s. Not only is this super uncomfortable to work in, it also makes the paint dry too fast for a good finish. So hitting the west side of the house in the morning may be your best bet. The trick is to evaluate your unique situation and plan accordingly.
After I finish up a bath remodel I’m working on this week, I have a client who has about 900 square feet of deck that needs a serious coat of paint. Will Mother Nature cooperate? I hope so.
Updated March 25, 2018.
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