When it comes to painting, especially exterior painting, don't think of it as applying a great swatch of color to a surface.
Think of it as preparing the surface to accept an "overcoat" that will protect it from the elements.
In fact, 50 percent of your total painting time should involve surface preparation, according to Larry Horton, store manager at Budeke's Paints in Fells Point. You have to have a "nice, tight, clean" surface before you do anything else, Mr. Horton says.
"You can spend $100 for a gallon of paint, and if you don't do the proper preparation, you might as well just spend $5," Mr. Horton says.
Anything that gets between the paint and the surface will interfere with the durability of the finish. Any kind of dirt, film, moisture, dust or loose paint needs to be taken off; any kind of loose or damaged surface material (like splintered or rotten TC wood) needs to be repaired or replaced.
The best paint jobs are three-coat jobs: primer and two finish coats.
Here are the steps professional painter Andrew Williams, of Charm City Contractors, advises when taking on an exterior painting job:
*Scrape off any loose paint first. The best thing is to remove all paint, Mr. Williams says, but that's hard to do. (Remember that the dust from lead paint is dangerous. Find out if you're dealing with lead paint and take precautions to avoid breathing the dust. If you strip with a heat gun, the danger is less, but you still need to wear a mask that will filter out the fumes.)
*Dig out old caulk around windows and doors. If the putty around window glass is in bad shape, dig it out and replace it. (Replace broken glass before you replace the putty.)
*Fill in pits and holes with exterior wood putty. (Check with your paint supplier for the variety most compatible with the paint you're using.)
*Sand the surface smooth.
*Wipe down the surface with mineral spirits. (Make sure it's dry before you try to paint; mineral spirits thin paint.)
*Apply a coat of primer and let it dry.
*Caulk any gaps, such as around windows and doors. (Buy the best caulk you can afford; ask the paint supplier what is most compatible with your paint.)
*Sand the primer lightly to improve adhesion of the first finish coat. Clean off the dust.
*Apply the first finish coat. Let it dry and sand it lightly. Clean off the dust.
*Apply second coat of finish.
If the wood is bare and seems dried out, it can be treated by adding a quart of boiled linseed oil to each gallon primer. While this will lead to a longer-lasting finish, it will also lead more immediately to a considerably longer drying time for the primer -- it could take as much as two or three days, depending on the weather. Obviously, this is too time-consuming for most contract painters, but Mr. Williams says: "I would do this on my own house."
The biggest decision you make on which paint to use is not what color. It's whether it's oil-based or water-based.
Up until five years ago, Mr. Horton says, oil-based paint was considered to hold up better.
Now that's changing.
"Acrylics hold their gloss and color for a longer period of time," says Rick Watson, technical adviser for Duron Paints Inc. in Beltsville, Md. "It's not unusual for oil paint to lose 50 percent of its gloss in the first 12 months."
However, Mr. Horton and Mr. Watson both note that oil paint is more "forgiving," especially if there's any peeling, flaking or "chalking" on the surface. Acrylics require a better base to adhere to.
The two men also agreed that both types of paint work best over oil-based primer. If the surface is already painted and you're not sure what kind of paint it is, you should definitely use an oil-based primer.
For most people, the issue is cleanup. Acrylic paint cleans up with water, but oil-based needs paint thinner (mineral spirits).
In most cases, once there's a good oil-based primer on the surface, acrylic paint is fine. In fact, there are some instances where you shouldn't use oil-based finish paint.
Acrylic finish paint is a real advantage on masonry or wood siding, Mr. Horton says, especially where there's no vapor barrier in the interior walls. An oil-based finish can trap moisture and cause paint to blister. Acrylic paint "breathes" and allows the moisture to escape without blistering.
Another reason to avoid oil-based paint is environmental. Oil-based paints contain solvents that evaporate into the air and can damage the earth's ozone layer.
Three states -- California, New York and New Jersey -- already have laws that mandate reduction in the amount of "volatile organic compounds" released into the air.
Mr. Watson said manufacturers are responding by reducing the solvents. The resulting paint has more solids -- pigments and resins -- so it costs more per gallon. However, Mr. Watson says, the coverage is extended, so the cost per square foot should be about the same.
As for the cost of paint, Mr. Horton notes that "If you spend money for a quality paint, with the proper surface preparation, paint is the least expensive way to improve your home."
Then he quotes the motto that hangs behind the counter in his store: "The true cost of paint is the cost per square foot per year."
Next: Interior painting.
Mr. Johnson is construction manager for Neighborhood Housin Services of Baltimore. Ms. Menzie is Home Editor of The Sun.
If you have questions, comments, tips or experiences to sharabout working on houses, write to us c/o HOME WORK, The Sun, 501 N. Calvert St., Baltimore, Md. 21278. Questions of general interest will be answered in the column; comments, tips and experiences will be reported in occasional columns.