How to Paint Your House's Exterior
For the cost of a few cases of exterior paint, plus some patching and sanding, you can have a whole new home
A fresh paint job has the power to totally transform the look of your house in less time and for less cash than any other remodeling project. That thin skin of resin and pigment also protects your investment, shielding it from sun, wind, and rain—until the paint begins to crack and peel, that is. Then it's time to button up with a couple of new coats. Properly applied, new paint should last for a good 15 years, provided you use top-quality materials, apply them with care (and with an eye on the weather), and, most important, clean and sand every surface first. Here's what you need to know to get a first-class finish on your home's exterior.
A thorough scrubbing is a must before painting any exterior surface. It removes the dirt and broken-down paint residues that keep fresh coats from adhering and gets rid of mildew that grows on paint in all but the most arid climates. Most contractors clean with pressure washers, but in the hands of someone unfamiliar with the equipment, these can gouge wood, shatter glass, and drive water behind siding and trim. Using a hose, a pump sprayer, and a scrub brush is slower but safer, and just as effective.
Before the scrubdown, protect nearby plants by misting their leaves and saturating the surrounding soil with water, pulling them away from the house, and shrouding them in fabric drop cloths. (Plants will cook under plastic.) Lay more drop cloths along the base of the walls to collect any falling paint debris. Walls should be wet down before getting scrubbed, then washed with a gallon of water mixed with 1 cup chlorine bleach and 1 cup of either a concentrated, phosphate-free cleaner, such as a trisodium phosphate (TSP) substitute, or Jomax House Cleaner. Working in sections, from the bottom to the top, will avoid streaks. Be sure to rinse walls well before the solution dries. Wood siding and trim should be ready to paint after a day or two of dry weather.
Paint that has peeled, bubbled, or blistered has got to go. But if lead is present—a strong possibility in houses built before 1978—you need to proceed with extra care. To lay any doubts to rest, you can send paint chip samples to a lab, such as Macs Lab's Home Free; for about $38, they'll give you a definitive answer.
If your paint does contain lead, you'll need to take special precautions during the scraping and sanding phases to protect yourself, your family, and the environment from toxic dust. If the paint is lead-free, you need only don a dust mask and lay down tarps to catch debris before tackling the most crucial part of the project.
New Orleans contractor Joseph Wallis did use a PaintShaver on this project to capture lead dust. This carbide-tipped angle grinder, which has a dust-collecting shroud that connects to a HEPA-filter vac, can be rented by mail from the manufacturer for about $50 a day.
Scraping paint by hand is a grueling task because you've got to attack it from every direction. But compared to power grinders and sanders, it's the least damaging way to remove the old layers. You can speed up the process by using a heating gun to soften the paint (as shown).
Safety First: Use a respirator when scraping paint by hand. Also, make sure you protect the surrounding work area—including any plants and shrubs—with a tarp covering.
Small random-orbit or pad sanders make this job go faster. (Wallis first covers these boundaries with Synkoloid patching compound so no edge is visible after sanding.) As shown, you want to make sure that there is a feathered, smooth transition from exposed wood to old paint. For areas that might get close scrutiny, you can follow up with a 100- or 120-grit rubdown to erase any scratches.
If less than half the old paint is left, however, it may be worth stripping it all off. Guertin gets rid of stubborn remnants using shrouded grinders (like the PaintShaver), infrared paint strippers (such as the Speedheater), or chemical strippers (like Multi-Strip), then smooths the wood with a course or two of sanding. When siding (or bank accounts) can't take the shock of a total strip job, Rich O'Neil, of Masterwork Painting in Bedford, Massachusetts, has successfully hidden rough, well-adhered paint under Peel Bond, a thick primer.
Safety First: When using a random-orbit sander, be sure to protect yourself from refuse with a respirator. For sanding by hand, a dust mask will do.
After the sanding is done, it's time to fill minor cracks and dents, repair any rot, and replace any pieces that are too far gone. (Wholesale replacement of wood siding or trim will likely require a carpenter.)
O'Neil patches shallow holes and divots with Ready Patch because it dries fast, sands smooth, and stays flexible. Deep cracks and rotten spots are best repaired with two-step epoxies, such as those made by Advanced Repair Technology. (For a step-by-step instructions, see Repairing Rot with Epoxy.) The days of using polyester auto-body fillers on wood are over. "They cure too hard," says Portland, Oregon–based painting contractor Kathleen George. "They look good at first, but then they peel away."
Hold off on caulking the cracks until everything has been primed. "Primer protects the wood when—not if—the caulk fails," says O'Neil.
Primers are formulated to penetrate, seal, and provide a good surface for the top coats to stick to. Use them over bare wood, Spackle, and epoxy, or over paint with a chalky, deteriorated surface. (If the paint surface is clean and sound, you can skip the priming step.)
Acrylic primers can be used on most surfaces, but on cedar or redwood, oil-based coatings are a must because they lock in these woods' reddish-brown "extractives," which will leach out and leave behind rusty stains if the wood is primed with a water-based product.
Painters often tint primer close to the color of the top coat, but Wallis thinks that's a recipe for "holidays," or missed spots. Instead, he tints his primer a contrasting color. "If I can see the color coming through, I know I need to apply more paint," he says. On the cottage shown in this story, he chose a gray-blue primer to go under a peach top coat.
If primer is sprayed on, "back-brushing" it immediately by hand will work the coating into every crack and crevice.
Tip: Spray exposed nailheads with a metal primer to prevent rust from bleeding through the paint.
When the primer is dry, caulk all small joints (less than ¼-inch-wide) in the siding and trim. Most pros use siliconized acrylics—paint won't stick to straight silicones—but Guertin and O'Neil like the new, more expensive urethane acrylics for their greater flexibility and longevity. O'Neil stresses that it's shortsighted to skimp on caulk. "If the joint fails, you're back to square one." Guertin uses the lifetime rating as his quality guide. "I don't expect 35-year caulk will last 35 years, but it should last longer than a 15-year caulk."
Deciding which paint to use has gotten much easier now that acrylic latexes have pushed oil-based paints almost to extinction. The acrylics offer superior performance (they don't harden with age, the way oils do, so they move and breathe without blistering), they don't mildew as readily, and they emit fewer VOCs, so they comply with new air-quality regulations. They also work over both oil- and water-based primers.
Oil paint still has a place in high-traffic areas such as wood steps and porch floors because of its superior wear resistance, and on steel and cast-iron railings, which benefit from oil's water repellency.
The last big decision is how to apply the paint. Most pros use paint sprayers because they're fast, but in inexperienced hands a high-powered sprayer can leave drips, thin coats, and a mist that may land on many things other than your siding. If you do hire a painter who uses a sprayer, make sure he is meticulous about removing, covering, or masking off everything in the area that might get hit with overspray: gutters, roofs, windows, shrubbery, walkways, cars—you name it.
Once you choose a paint brand, the pros advise against additives, such as mildewcides. But they will add conditioners such as Floetrol (for latex) or Penetrol (for oils) to slow drying times in hot weather so brush and lap marks don't show, and to make paint more sprayable.
Every painting job develops a unique choreography as ladders go up and come down and tarps are unrolled and folded up. But two basic principles remain: 1) Start at the top and work down. 2) Work in the shade, out of the sun's glare. As the dance proceeds, keep an eye on the weather. Rain can wash freshly applied latex right off the wall, and a temperature dip below 50 degrees F two days after application can interfere with adhesion and curing and dull the sheen of glossy paints. (Latexes like Sherwin-Williams's Duration and Benjamin Moore's MoorGard Low Lustre are formulated to tolerate temps as low as 35 and 40 degrees, respectively.)
Do-it-yourselfers are best off using a brush for maximum control. You may end up with a better quality job, to boot. Says Kathleen George, "With a brush, I know that I've inspected every square inch of a house." Mini rollers speed application on clapboards and trim but should be followed immediately with a brush.
Whichever application method you end up using, the pros are universal in their insistence that two top coats are always better than one. Says O'Neil, "It's one of the real secrets of a long-lasting paint job."