Television ads for exterior paint should probably be accompanied by the same mix of disclaimers required for prescription drug commercials. A high quality exterior paint will protect and beautify your home, but only if you first perform the proper surface prep and apply the coating under ideal weather conditions. Any exterior coating can be applied on a sunny day when temperatures fall between 50 and 85 degrees Fahrenheit. But if the mercury nears the freezing mark, you may need to seek out a special remedy.
First, Do No Harm
Before applying a new coat of exterior paint, examine the old painted surfaces for any any peeling, flaking, cracking, blistering or chalking. Do not disturb a damaged paint surface if the home was constructed before 1978 -- when the federal ban on lead-based paint took effect. In that case, perform a safety checkup of your walls using an EPA-certified lead test kit. If testing indicates the presence of lead, consult your regional health department or a registered lead abatement specialist before disturbing the substrate.
Take Your Home's Temperature
Before painting, check the weather report for the day's temperature and rain forecast. Ideally, you should only paint on a rain-free day when temperatures are likely to remain steady throughout your paint's expected drying time. But you aren't applying paint to the air, you're painting a home's walls. On days when the mercury approaches either extreme of the paint manufacturer's recommended application temperatures, a surface thermometer will give you a more accurate reading. Many paint stores offer inexpensive surface thermometers for purchase or loan.
Healthy Range of Temperatures
Conventional exterior latex paints can be applied when outdoor temperatures fall between 60 and 85 degrees F, although some brands advise painters that they can work on days as chilly as 50 degrees or as warm as 90 degrees. Most exterior alkyd or oil paints can be used at temperatures between 40 and 90 degrees F. For best results, read the specific instructions on the paint can's label or consult the manufacturer directly.
A Better Cold Treatment
A special variety of exterior latex paints is designed for use in early spring and late fall when the thermometer reads as low as 35 degrees F. These paints combine all the advantages of water-based coatings -- including rapid drying times, easy soap and water cleanup, and reduced environmental impact -- while surpassing the low temperature performance of alkyd paints. Look for exterior latex paints with "cold weather" or "low-temp" claims featured prominently on their labels. These cold weather paints perform as well as conventional exterior coatings at warmer temperatures too.